WO2015166914A1 - Piezoelectric element, method for manufacturing piezoelectric element, and piezoelectric vibrator provided with piezoelectric element - Google Patents

Piezoelectric element, method for manufacturing piezoelectric element, and piezoelectric vibrator provided with piezoelectric element Download PDF

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WO2015166914A1
WO2015166914A1 PCT/JP2015/062706 JP2015062706W WO2015166914A1 WO 2015166914 A1 WO2015166914 A1 WO 2015166914A1 JP 2015062706 W JP2015062706 W JP 2015062706W WO 2015166914 A1 WO2015166914 A1 WO 2015166914A1
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piezoelectric ceramic
piezoelectric
powder
piezoelectric element
internal electrode
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French (fr)
Japanese (ja)
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小川　弘純
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株式会社村田製作所
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/05—Manufacture of multilayered piezoelectric or electrostrictive devices, or parts thereof, e.g. by stacking piezoelectric bodies and electrodes
    • H10N30/053—Manufacture of multilayered piezoelectric or electrostrictive devices, or parts thereof, e.g. by stacking piezoelectric bodies and electrodes by integrally sintering piezoelectric or electrostrictive bodies and electrodes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/09—Forming piezoelectric or electrostrictive materials
    • H10N30/093—Forming inorganic materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/09—Forming piezoelectric or electrostrictive materials
    • H10N30/093—Forming inorganic materials
    • H10N30/097—Forming inorganic materials by sintering
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/50—Piezoelectric or electrostrictive devices having a stacked or multilayer structure
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/85—Piezoelectric or electrostrictive active materials
    • H10N30/853—Ceramic compositions

Definitions

  • the present invention relates to a piezoelectric element, a method for manufacturing the piezoelectric element, and a piezoelectric vibrator including the piezoelectric element.
  • piezoelectric elements using piezoelectric ceramics such as unimorph piezoelectric actuators and bimorph actuators are widely used in various piezoelectric vibrators such as piezoelectric speakers and sensors.
  • Patent Document 1 discloses a piezoelectric bimorph in which a piezoelectric ceramic element is bonded to both sides of an intermediate plate made of a metal plate of SK steel containing carbon by an organic adhesive. An element is disclosed (see the lower right column on page 3 to the upper left column on page 4 of Patent Document 1).
  • Patent Document 2 Japanese Patent Application Laid-Open No. 2013-219250
  • a piezoelectric paste is applied to at least one main surface of a metal plate, and then fired in a non-oxidizing atmosphere, so that it is ultrathin.
  • a method for obtaining a unimorph-type and bimorph-type piezoelectric ceramic electronic component having a large displacement is disclosed (see paragraph [0013] of Patent Document 2).
  • the piezoelectric bimorph element described in Patent Document 1 is manufactured by bonding piezoelectric ceramic elements to the surfaces on both sides of the intermediate plate with an organic adhesive, there is a limit to thinning the piezoelectric ceramic elements. . That is, in order to bond the piezoelectric ceramic element to the intermediate plate, it is necessary to cut the piezoelectric ceramic element made of sintered ceramic or to bond the piezoelectric ceramic element to the intermediate plate. In this case, the thickness of the piezoelectric ceramic element needs to be at least about 100 ⁇ m.
  • the thickness of the piezoelectric ceramic element is less than 100 ⁇ m, for example, when the piezoelectric ceramic element is cut or when the piezoelectric ceramic element is pressed and bonded to the intermediate plate, a micro crack is generated in the piezoelectric ceramic element. This is because the piezoelectric ceramic element is damaged.
  • the linear thermal expansion coefficient of the metal plate and the linear thermal expansion coefficient of the piezoelectric body formed on the metal plate are different, so that the piezoelectric body is not cracked when the piezoelectric paste is fired. Even when the piezoelectric material is generated or the piezoelectric material can be formed by firing the piezoelectric paste, there is a problem that the piezoelectric material is peeled off from the metal plate during the cooling.
  • an object of the present invention is to suppress the occurrence of microcracks and peeling in a piezoelectric ceramic.
  • a piezoelectric element according to the present invention includes a sintered metal including a base metal and a piezoelectric ceramic provided integrally with the sintered metal, and the piezoelectric ceramic includes a perovskite type compound as a main substance, and the main substance is niobium.
  • the content of the main substance is 90 mol% or more with respect to the total molar quantity of all substances contained in the piezoelectric ceramic, including alkali metal and oxygen.
  • the piezoelectric element may further include an external electrode provided on the piezoelectric ceramic so as to face the sintered metal, and the external electrode is preferably provided integrally with the piezoelectric ceramic.
  • the piezoelectric ceramic preferably has one main surface and the other main surface, and the sintered metal is preferably provided on one main surface and the other main surface of the piezoelectric ceramic so as to sandwich the piezoelectric ceramic.
  • the thickness of the piezoelectric ceramic is preferably 100 ⁇ m or less.
  • the thickness of the sintered metal is preferably 1.7 ⁇ m or more and 5.1 ⁇ m or less.
  • the piezoelectric element may further include an internal electrode provided inside the piezoelectric ceramic, and the internal electrode is preferably provided integrally with the piezoelectric ceramic.
  • the internal electrode includes a first internal electrode and a second internal electrode.
  • the first internal electrode extends from the first side surface of the piezoelectric ceramic so as to face the sintered metal
  • the second internal electrode extends from the second side surface of the piezoelectric ceramic so as to face the sintered metal, and reaches the first side surface of the piezoelectric ceramic.
  • the first internal electrode and the second internal electrode may be provided so as to face each other with a space therebetween.
  • the piezoelectric element includes a first connection electrode provided on the first side surface of the piezoelectric ceramic, and a second connection electrode provided on the second side surface of the piezoelectric ceramic.
  • One internal electrode and the sintered metal may be electrically connected, and the second connection electrode may electrically connect the second internal electrode and the external electrode.
  • the base metal preferably contains at least one selected from the group consisting of nickel, copper, and aluminum.
  • a method for manufacturing a piezoelectric element according to the present invention includes a sintered metal including a base metal and a piezoelectric ceramic provided integrally with the sintered metal, the piezoelectric ceramic including a perovskite type compound as a main material, A method for producing a piezoelectric element comprising niobium, an alkali metal, and oxygen, wherein the content of the main substance is 90 mol% or more with respect to the total molar quantity of all substances contained in the piezoelectric ceramic, A piezoelectric element manufacturing method including a first step of superimposing a base metal powder and a second step of co-sintering the superposed piezoelectric ceramic powder and the base metal powder.
  • the first step in the method for manufacturing a piezoelectric element according to the present invention further includes a step of superposing internal electrode powders between a plurality of piezoelectric ceramic powders, and the piezoelectric ceramic powder and base metal powder superposed in the second step. And the internal electrode powder may be co-sintered.
  • the second step in the method for manufacturing a piezoelectric element according to the present invention is a substance containing at least one or more piezoelectric ceramic powder and base metal powder selected from the group consisting of ZrO 2 , Al 2 O 3 and SiO 2. It is preferable to sandwich the ceramics with the main material and co-sinter.
  • the second step in the method for manufacturing a piezoelectric element according to the present invention is preferably performed in an atmosphere having an oxygen partial pressure equal to or lower than 1000 times the oxygen partial pressure at which the base metal and the base metal oxide are in equilibrium.
  • a piezoelectric vibrator according to the present invention includes the above-described piezoelectric element.
  • the load applied to the piezoelectric ceramic can be suppressed, the occurrence of microcracks and peeling in the piezoelectric ceramic can be suppressed.
  • FIG. 2 is a schematic cross-sectional view of the piezoelectric element according to Embodiment 1.
  • FIG. FIG. 3 is a schematic cross-sectional view for illustrating an example of a method for manufacturing the piezoelectric element according to the first embodiment.
  • FIG. 3 is a schematic cross-sectional view for illustrating an example of a method for manufacturing the piezoelectric element according to the first embodiment.
  • FIG. 3 is a schematic cross-sectional view for illustrating an example of a method for manufacturing the piezoelectric element according to the first embodiment.
  • FIG. 3 is a schematic cross-sectional view for illustrating an example of a method for manufacturing the piezoelectric element according to the first embodiment.
  • FIG. 6 is a schematic cross-sectional view of a piezoelectric element according to Embodiment 2.
  • FIG. FIG. 10 is a schematic cross-sectional view for illustrating an example of a method for manufacturing the piezoelectric element according to the second embodiment.
  • FIG. 10 is a schematic cross-sectional view for illustrating another example of the method for manufacturing the piezoelectric element according to the second embodiment.
  • 2 is a schematic cross-sectional view of a laminated body before co-sintering in Example 1.
  • FIG. 6 is a schematic cross-sectional view of a piezoelectric element in a modification of the first embodiment. It is a figure which shows the electric charge generated with respect to time when a three-point bending force is repeatedly applied to the piezoelectric element of Example 3-2.
  • FIG. 1 shows a schematic cross-sectional view of the piezoelectric element of the first embodiment.
  • the piezoelectric element according to Embodiment 1 shown in FIG. 1 has, for example, a flat plate shape.
  • the piezoelectric element includes a sintered metal 1 including a base metal, a piezoelectric ceramic 2 provided integrally with the sintered metal 1 on the sintered metal 1, and an external electrode 3 provided on the piezoelectric ceramic 2.
  • the sintered metal 1 and the external electrode 3 are provided on the lower surface and the upper surface of the piezoelectric ceramic 2 that face each other, and the sintered metal 1 and the external electrode 3 face each other through the piezoelectric ceramic 2. .
  • the sintered metal 1 containing a base metal has a structure in which a plurality of base metal crystal grains are fixed in contact with each other.
  • the base metal is a metal other than gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os).
  • Sintered metal refers to a metal powder that has been in a metal powder state prior to the sintering of the piezoelectric ceramic, but has been co-sintered simultaneously with the piezoelectric ceramic to form a thin plate metal.
  • the internal electrode is included in the sintered metal in a broad sense, but here, the sintered metal in which the piezoelectric ceramic exists on both sides of the main surface is defined as “internal electrode”, and the piezoelectric ceramic is formed only on one side of the main surface.
  • the existing sintered metal is defined as “sintered metal”.
  • the base metal used for the sintered metal 1 is at least one selected from the group consisting of nickel (Ni), copper (Cu), and aluminum (Al). It is preferable to use a metal containing Ni, more preferably a metal containing at least one of Ni and Cu, and even more preferably Ni.
  • the piezoelectric ceramic 2 contains a perovskite type compound as a main substance, and the main substance contains niobium (Nb), an alkali metal, and oxygen (O), and the total of all the substances contained in the piezoelectric ceramic 2 is included.
  • the content of the main substance with respect to the molar amount is 90 mol% or more.
  • the presence and content of the perovskite type compound as the main substance in the piezoelectric ceramic can be determined by an X-ray diffraction method. That is, the presence of the perovskite type compound can be confirmed by the appearance of an X-ray diffraction peak at a specific position in the X-ray diffraction pattern obtained by the X-ray diffraction method.
  • Acta Crystallogr., Sec. A, 34 309 (1978) describes powder X-ray diffraction data of (Na 0.35 K 0.65 ) NbO 3 .
  • the intensity ratio of each peak and the peak position with respect to the interplanar spacing d are similar, it can be determined as a perovskite type compound containing alkali metal and niobium.
  • the content of the perovskite compound and the magnitude of the X-ray diffraction peak intensity are in a proportional relationship, the content of the perovskite compound and the content of the perovskite compound and the other substances are known using a known sample.
  • a calibration curve showing the relationship with the magnitude of the X-ray diffraction peak intensity can be created. Based on the calibration curve, the content of the perovskite type compound as the main substance in the piezoelectric ceramic can be determined.
  • the content (% by weight) of each constituent element contained in the piezoelectric ceramic can be obtained by inductively coupled high-frequency plasma spectroscopic analysis (ICP spectroscopic analysis). Since the crystal structure of the piezoelectric ceramic is found by the X-ray diffraction method, it is possible to know which constituent element atom is located at which site of the crystal structure of the piezoelectric ceramic. Specifically, it can be judged as a perovskite compound containing an alkali metal, niobium and oxygen if it is similar to the diffraction data of (Na 0.35 K 0.65 ) NbO 3 described above. Thereby, it can be confirmed that 90 mol% or more of the perovskite type compound containing Nb, alkali metal and O is contained as a main substance with respect to the total molar amount of all the substances contained in the piezoelectric ceramic.
  • ICP spectroscopic analysis inductively coupled high-frequency plasma spectroscopic analysis
  • the perovskite type compound as the main substance may contain tantalum (Ta).
  • auxiliary substances other than the main substance include, for example, barium (Ba), strontium (Sr), calcium (Ca), zirconium (Zr), titanium (Ti), tin (Sn), manganese ( Mn), Ni, scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), At least one selected from the group consisting of gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) Can be mentioned.
  • the piezoelectric ceramic 2 is provided integrally with the sintered metal 1. That is, at the bonding interface between the sintered metal 1 and the piezoelectric ceramic 2, the base metal crystal grains contained in the sintered metal 1 and the piezoelectric ceramic crystal grains contained in the piezoelectric ceramic 2 are in contact and fixed together. The sintered metal 1 and the piezoelectric ceramic 2 are integrated, and the sintered metal 1 and the piezoelectric ceramic 2 are joined.
  • the sintered metal exists as a base metal powder before firing the piezoelectric ceramic, but is sintered together with the piezoelectric ceramic and the base metal powder is sintered.
  • the external electrode 3 includes, for example, a conductive material such as a base metal, and is not particularly limited as long as it is a member that can inject current from the outside into the piezoelectric ceramic 2 or take out current from the piezoelectric ceramic 2.
  • the external electrode is formed, for example, by sputtering, vapor deposition, or metal paste baking after sintering the piezoelectric ceramic.
  • the external electrode 3 is preferably provided integrally with the piezoelectric ceramic 2. That is, all the electrodes formed on the piezoelectric element may be a sintered metal.
  • the piezoelectric ceramic 2 and the external electrode 3 are provided integrally, the crystal grains of the piezoelectric ceramic included in the piezoelectric ceramic 2 and the external electrode 3 are included at the bonding interface between the piezoelectric ceramic 2 and the external electrode 3.
  • the bonding between the piezoelectric ceramic 2 and the external electrode 3 can be made stronger by the contact and fixing with the crystal grains of the conductive material such as the base metal, so that the external electrode 3 from the piezoelectric ceramic 2 can be made stronger. The occurrence of peeling can be more effectively suppressed.
  • the piezoelectric ceramic powder 2a is a substance that becomes the piezoelectric ceramic 2 by co-sintering described later.
  • Piezoelectric ceramic powder 2a is prepared by, for example, weighing at least Nb oxide powder and alkali metal carbonate powder so that the content of a perovskite type compound as a main substance is 90 mol% or more, and then mixing them. Then, a piezoelectric ceramic raw material powder is prepared, calcined and then pulverized.
  • the piezoelectric ceramic powder 2a may be combined with other substances or not combined with other substances, and may be in a form other than powder, such as a sheet, a tape, or a paste.
  • the base metal powder 1a is a substance that becomes a sintered metal 1 containing a base metal by co-sintering described later.
  • the base metal powder 1a may be combined with other substances or not combined with other substances, and may be in a form other than powder, such as a sheet, tape, or paste.
  • the tape shape is uniform, and when the piezoelectric element is thin, the base metal powder is uniformly sintered, so that the piezoelectric element is not damaged. Therefore, the form of the base metal powder is more preferably a sheet shape or a tape shape.
  • the base metal powder 1a and the piezoelectric ceramic powder 2a are overlaid.
  • the method of superposing the base metal powder 1a and the piezoelectric ceramic powder 2a is not particularly limited.
  • a method of installing a sheet-like, tape-like, or paste-like piezoelectric ceramic powder 2a on the base metal powder 1a can be used.
  • these piezoelectric elements are made of ZrO. 2 , It is preferable to sandwich and co-sinter a material containing at least one selected from the group consisting of Al 2 O 3 and SiO 2 as a main material.
  • the ceramic may be dense or may have voids.
  • the ceramic may be plate-shaped, massive, or curved. By doing in this way, the unintended deformation
  • the co-sintering of the base metal powder 1a and the piezoelectric ceramic powder 2a has an oxygen partial pressure at which the base metal contained in the base metal powder 1a (base metal contained in the sintered metal 1) and the oxide of the base metal are in equilibrium. It is preferable to carry out in an atmosphere having an oxygen partial pressure of 1000 times or less. When the oxygen partial pressure of the atmosphere is higher than the equilibrium oxygen partial pressure of the base metal and the base metal oxide, the base metal oxidation tends to proceed.
  • the base metal oxidation does not proceed rapidly, so the base metal and base metal oxidation Even when the equilibrium oxygen partial pressure with the oxide is 1000 times the upper limit of the oxygen partial pressure of the co-sintering atmosphere, the sintering of the base metal powder 1a can proceed while suppressing the oxidation of the base metal, for example, NiO or The sintered metal 1 can be formed while suppressing the inclusion of base metal oxides such as copper oxide (Cu 2 O).
  • the oxygen partial pressure in the atmosphere during co-sintering can be calculated from, for example, the oxygen concentration measured using a zirconia oxygen concentration sensor.
  • the zirconia oxygen concentration sensor generates an electromotive force determined by the ratio of the oxygen concentration in the reference gas and the oxygen concentration in the measurement gas. It is calculated by the following formula.
  • E electromotive force (V)
  • R gas constant (8.3145 (J ⁇ mol ⁇ 1 ⁇ K ⁇ 1 ))
  • T absolute temperature (K)
  • n reaction Number of electrons contained
  • F Faraday constant (9.649 ⁇ 10 4 (C ⁇ mol ⁇ 1 ))
  • Pr oxygen concentration in the reference gas (usually air)
  • Pm oxygen concentration in the measurement gas.
  • FIG. 6 shows the relationship between the logarithm of the equilibrium oxygen partial pressure of Ni and NiO (Ni—NiO equilibrium oxygen partial pressure) and the temperature.
  • FIG. 7 shows the relationship between the logarithm of the equilibrium oxygen partial pressure (Cu—Cu 2 O equilibrium oxygen partial pressure) of Cu and Cu 2 O and the temperature.
  • the relationship between the equilibrium reaction between metal and oxide and the partial pressure of oxygen and temperature can be analyzed thermodynamically and can generally be understood from the Ellingham diagram.
  • the external electrode 3 is formed on the piezoelectric ceramic 2 so as to face the sintered metal 1, whereby the piezoelectric element of the first embodiment can be manufactured.
  • the external electrode 3 is formed on the surface of the piezoelectric ceramic 2 facing the sintered metal 1 in the sintered metal 1 and the piezoelectric ceramic 2 which have already been co-sintered and integrated.
  • the material for forming the external electrode 3 only needs to be electrically conductive, such as silver, gold, platinum, nickel, or copper.
  • the method for forming the external electrode 3 is not particularly limited, and examples thereof include a sputtering method, a vapor deposition method, and a method for baking metal powder. After the sintered metal 1 and the piezoelectric ceramic 2 are co-sintered, the external electrode 3 is formed on the surface of the piezoelectric ceramic 2 facing the sintered metal 1 by, for example, sputtering, vapor deposition, or metal powder or metal powder paste. Can be formed by a method such as baking.
  • the sintered metal 1 and the piezoelectric ceramic 2 are formed by co-sintering the base metal powder 1a and the piezoelectric ceramic powder 2a, the metal plate and the piezoelectric as in the conventional patent document 2 are formed. The generation of microcracks due to the difference in linear thermal expansion coefficient from the body is suppressed. Moreover, since the piezoelectric ceramic 2 has a smaller linear thermal expansion coefficient than the base metal of the sintered metal 1, the piezoelectric ceramic 2 receives a compressive stress from the sintered metal 1 during cooling after co-sintering. Since the sintered metal 1 and the piezoelectric ceramic 2 are integrally formed and have high bonding strength, peeling of the piezoelectric ceramic 2 due to the compressive stress can also be suppressed.
  • the occurrence of microcracks and peeling in the piezoelectric ceramic 2 can be suppressed.
  • the manufacturing cost due to the reduction in the number of steps can be reduced.
  • the sintered metal 1 and the piezoelectric ceramic 2 can be formed by co-sintering the base metal powder 1a and the piezoelectric ceramic powder 2a.
  • Each of the metal 1 and the piezoelectric ceramic 2 can be formed thin. Therefore, in the first embodiment, by applying a thin film of the piezoelectric ceramic 2 (thickness of the piezoelectric ceramic 2: 100 ⁇ m or less), it is possible to reduce the applied voltage when driven by the same electric field. Since a circuit for increasing the voltage is not necessary, the circuit can be simplified, which leads to a reduction in manufacturing cost.
  • each of the sintered metal 1 and the piezoelectric ceramic 2 can be made thinner. Compared with Document 1 and Patent Document 2, a piezoelectric element having a large displacement can be obtained.
  • the metal plate of patent document 2 can also be thinned by repeatedly passing between rolls etc., since a man-hour increases, manufacturing cost increases and the thinned metal plate is aluminum, for example Since it becomes easy to sag like foil, handling becomes difficult.
  • the shape of the piezoelectric element is not limited to a flat plate shape, and may be formed in a shape other than a flat plate shape such as a roll shape or a corrugated plate shape.
  • the present invention is particularly effective when the piezoelectric element has a shape other than a flat plate shape.
  • FIG. 16 shows a piezoelectric element according to a modification of the first embodiment.
  • the piezoelectric element of the modification of the first embodiment is different from the piezoelectric element of the first embodiment in that the external electrode 3 in the first embodiment is a sintered metal 1.
  • the piezoelectric ceramic 2 is formed in a plate shape having one main surface and the other main surface.
  • the sintered metal 1 is provided on one main surface and the other main surface of the piezoelectric ceramic 2 so as to sandwich the piezoelectric ceramic 2. Even in such a case, the same effect as in the first embodiment can be obtained.
  • FIG. 8 is a schematic cross-sectional view of the piezoelectric element according to the second embodiment.
  • the piezoelectric element according to the second embodiment shown in FIG. 8 has, for example, a substantially rectangular parallelepiped piezoelectric ceramic 2 formed integrally with the sintered metal 1.
  • the piezoelectric ceramic 2 includes two first internal electrodes 11 and two second internal electrodes 12 therein, and the piezoelectric ceramic 2 has first and second side surfaces 21 and 22 facing each other.
  • the first connection electrode 31 and the second connection electrode 32 are provided.
  • the number of the first internal electrodes 11 and the number of the second internal electrodes 12 is two, but the number of the first internal electrodes 11 and the number of the second internal electrodes 12 is particularly limited. It may be one by one, or three or more. Further, the number of the first internal electrodes 11 and the number of the second internal electrodes 12 are not necessarily the same and may be different.
  • the above-mentioned substantially rectangular parallelepiped shape includes not only a rectangular parallelepiped shape but also a rectangular parallelepiped shape having rounded corners, a rectangular parallelepiped shape having a curved surface and / or a curved surface.
  • the first internal electrodes 11 extend from the first side surface 21 toward the second side surface 22 so as to face the sintered metal 1, respectively.
  • One end of the electrode 11 is located in the first side surface 21, but the other end does not reach the second side surface 22.
  • Each of the second internal electrodes 12 extends from the second side surface 22 toward the first side surface 21 so as to face the sintered metal 1, and one end of the second internal electrode 12 is Although it is located in the second side surface 22, the other end does not reach the first side surface 21.
  • the first internal electrode 11 and the second internal electrode 12 are alternately arranged one by one along the thickness direction of the piezoelectric ceramic 2 and spaced apart from each other.
  • one end of the first connection electrode 31 provided on the first side surface 21 of the piezoelectric ceramic 2 is electrically connected to one end of each of the two first internal electrodes 11 located in the first side surface 21.
  • the other end of the first connection electrode 31 is electrically connected to the sintered metal 1.
  • the first connection electrode 31 electrically connects the two first connection electrodes 21 and the sintered metal 1.
  • one end of the second connection electrode 32 provided on the second side surface 22 of the piezoelectric ceramic 2 facing the first side surface 21 is two second internal electrodes located in the second side surface 22.
  • the other end of the second connection electrode 32 is electrically connected to the external electrode 3.
  • the second connection electrode 32 electrically connects the two second connection electrodes 12 and the external electrode 3.
  • the first internal electrode powder 11a is a substance that becomes the first internal electrode 11 by co-sintering described later
  • the second internal electrode powder 12a is a second internal electrode by co-sintering described later. It is a substance that becomes 12.
  • the first internal electrode powder 11a and the second internal electrode powder 12a for example, those containing a conductive material such as a base metal can be used.
  • the first internal electrode powder 11a and the second internal electrode powder 12a are also combined with other materials or not combined with other materials, for example, in the form of a sheet, tape, paste, etc. It may be in a form other than powder.
  • the base metal powder 1a, the piezoelectric ceramic powder 2a, the second internal electrode powder 12a, the piezoelectric ceramic powder 2a, the first internal electrode powder 11a, and the piezoelectric ceramic are formed on the surface of the substrate 41.
  • the powder 2a, the second internal electrode powder 12a, the piezoelectric ceramic powder 2a, the first internal electrode powder 11a, and the piezoelectric ceramic powder 2a are co-sintered in a state where they are superposed in this order.
  • the piezoelectric element which consists of the piezoelectric ceramic 2 containing an internal electrode, and the sintered metal 1
  • the powder 12a is sandwiched between ceramics mainly composed of a substance containing at least one selected from the group consisting of ZrO 2 , Al 2 O 3 and SiO 2 and co-sintered.
  • the ceramic described above may be dense or may have voids.
  • the above-mentioned ceramic may be plate-shaped, lump-shaped, or may have a curved surface. By doing in this way, the unintended deformation
  • the external electrode 3 is formed on the piezoelectric ceramic 2 so as to face the sintered metal 1, and the first side surface 21 and the second side surface 22 of the piezoelectric ceramic 2 are respectively first.
  • the connection electrode 31 and the second connection electrode 32 the piezoelectric element of the second embodiment can be manufactured.
  • the formation method of the 1st connection electrode 31 and the 2nd connection electrode 32 is not specifically limited, For example, after formation of the external electrode 3, to the 1st side surface 21 and the 2nd side surface 22 of the piezoelectric ceramic 2, respectively.
  • the first connection electrode 31 and the second connection electrode 32 can be formed by baking metal or the like.
  • the piezoelectric ceramic powder 2a As shown in the schematic cross-sectional view of FIG. 10, from the surface side of the base material 41, the piezoelectric ceramic powder 2a, the first internal electrode powder 11a, the piezoelectric ceramic powder 2a, the second internal electrode powder 12a, and the piezoelectric ceramic.
  • the powder 2a, the first internal electrode powder 11a, the piezoelectric ceramic powder 2a, the second internal electrode powder 12a, the piezoelectric ceramic powder 2a, and the base metal powder 1a may be placed in this order to perform co-sintering.
  • the external electrode 3 is preferably provided integrally with the piezoelectric ceramic 2. That is, all the electrodes formed on the piezoelectric element may be a sintered metal and an internal electrode.
  • the sintered metal 1 and the piezoelectric ceramic 2 can be integrally formed by co-sintering the base metal powder 1a and the piezoelectric ceramic powder 2a. The occurrence of microcracks and peeling in the ceramic 2 can be suppressed.
  • K 2 CO 3 , Na 2 CO 3 , Li 2 CO 3 , Nb 2 O 5 , CaCO 3 , and ZrO 2 was weighed so that .53: 0.02.
  • each powder of ZrO 2 , MnCO 3 and Yb 2 O 3 is adjusted so that ZrO 2 is 3 mol, MnO is 5 mol, and Yb 2 O 3 is 0.25 mol. Weighed.
  • the powder weighed as described above is put into a pot mill containing PSZ balls, and the piezoelectric ceramic raw material powder is mixed by wet mixing by rotating the pot mill for about 90 hours using ethanol as a solvent. Obtained.
  • the obtained piezoelectric ceramic raw material powder is dried, calcined at a temperature of 900 ° C., and then pulverized to obtain [100 ⁇ 0.98 (K 0.45 N 0.53 Li 0.02 ) NbO 3 ⁇ 0. 02CaZrO 3 ⁇ + 3ZrO 2 + 5MnO + 0.25Yb 2 O 3 ] was obtained.
  • the piezoelectric ceramic powder obtained as described above is put into a pot mill together with an organic binder, a dispersant, acetone, a plasticizer, and PSZ balls, and thoroughly mixed in a wet manner while rotating the pot mill.
  • the sheet was formed by the method to obtain a piezoelectric ceramic sheet.
  • Ni powder and an organic binder were put in a pot mill and mixed well while rotating, and sheet molding was performed by a doctor blade method to produce a base metal powder sheet.
  • a base metal powder sheet 101a which will later become a sintered metal, is pasted on the PET film 141, and the piezoelectric ceramic sheet 102a and Ni paste are applied to the base metal powder sheet 101a.
  • the internal electrode powders 111a thus obtained were alternately laminated one by one.
  • the thickness of the base metal powder sheet 101a was 5 ⁇ m
  • the thickness of the piezoelectric ceramic sheet 102a was 5 ⁇ m
  • the thickness of the internal electrode powder 111a was 1 ⁇ m.
  • the Ni—NiO equilibrium oxygen partial pressure was reduced to the 0.5 digit reduction side (oxygen partial pressure 1 / 3.16 of the Ni—NiO equilibrium oxygen partial pressure).
  • the sintered metal and the piezoelectric ceramic are integrally formed from the sample in which the sintered metal is produced with the sheet by co-sintering at a temperature of 1000 ° C. to 1160 ° C. for 2 hours in an atmosphere adjusted to be
  • the piezoelectric element of Example 1 in which no crack was generated was obtained.
  • a sample provided with Ni paste was also prepared instead of the base metal powder sheet 101a, which later became a sintered metal.
  • the thickness of the Ni paste was 5 ⁇ m, the same as in Example 1.
  • nonuniform shrinkage of Ni due to sintering occurred due to uneven application of the paste, and cracks occurred in the piezoelectric element.
  • microcracks was performed by observing the surface of the piezoelectric ceramic with a metal microscope or an electron microscope.
  • the piezoelectric element of Example 1 was cut and the cross section was polished, and then observed with a scanning electron microscope. The result is shown in FIG.
  • the thickness of the sintered metal 101 was 4.8 ⁇ m
  • the thickness of the piezoelectric ceramic 102 was 5.1 ⁇ m
  • the thickness of the internal electrode 111 was 1.6 ⁇ m. .
  • the surface of the sintered metal 101 of the piezoelectric element of Example 1 was similarly observed with a scanning electron microscope. The result is shown in FIG. As shown in FIG. 13, on the surface of the sintered metal 101 of the piezoelectric element of Example 1, a structure in which a plurality of Ni crystal grains were fixed in contact with each other was observed.
  • the surface of the rolled Ni plate of the piezoelectric element of the comparative example was similarly observed with a scanning electron microscope. The result is shown in FIG. As shown in FIG. 15, a plurality of Ni crystal grains such as the surface of the sintered metal 101 of the piezoelectric element of Example 1 are in contact with each other and fixed to the surface of the rolled Ni plate of the piezoelectric element of the comparative example. No structure was observed.
  • Example 2 Piezoelectric ceramic powder produced in the same manner as in Example 1 was processed into a paste by kneading together with a solvent and varnish. The paste-processed piezoelectric ceramic powder was applied on the surface of the PET film with a thickness of 5 ⁇ m and dried. After drying, Ni paste as an internal electrode powder was applied by a screen printing method to a thickness of 1 ⁇ m and dried.
  • Example 3 Piezoelectric ceramic powder was processed into a sheet by a doctor blade method to obtain a piezoelectric ceramic sheet.
  • base metal powder made of Ni powder is put into a pot mill together with an organic binder, dispersant, acetone, plasticizer, and PSZ balls, mixed thoroughly in a wet manner while rotating the pot mill, and sheet molding is performed by the doctor blade method.
  • a sheet-like base metal sheet was obtained.
  • the thickness of the piezoelectric ceramic sheet and the base metal sheet was changed, and the base metal sheet, the piezoelectric ceramic sheet, and the base metal sheet were superposed in this order.
  • Example 16 was obtained by performing hydrostatic pressure pressurization with respect to what laminated
  • the cross section of the piezoelectric element of Example 3 was mirror-polished, and the damaged state of the sintered metal and the piezoelectric ceramic was confirmed using a scanning electron microscope (SEM). Moreover, the presence or absence of conduction of the sintered metal was confirmed.
  • the thickness of the piezoelectric ceramic sheet is 90.0 ⁇ m
  • the thickness of the sintered metal is 0.8 ⁇ m, 1.7 ⁇ m, 2.1 ⁇ m, 5.1 ⁇ m, 6.2 ⁇ m, and 12.4 ⁇ m, respectively.
  • 3 piezoelectric elements were produced. And the conduction
  • the thicknesses of the sintered metal with which particularly good conduction was obtained were 1.7 ⁇ m, 2.1 ⁇ m, and 5.1 ⁇ m.
  • the results are shown in Table 1. Therefore, from the viewpoint of obtaining good conduction of the sintered metal, the thickness of the sintered metal is preferably 1.7 ⁇ m or more and 5.1 ⁇ m or less.
  • Example 3 is the same as Example 3 except that the thickness of the sintered metal is 2.1 ⁇ m and the thickness of the piezoelectric ceramic sheet is 5.0 ⁇ m, 15.0 ⁇ m, and 25.0 ⁇ m.
  • a piezoelectric element of -1 was produced. The damaged state of each piezoelectric element in Example 3-1 was confirmed. As a result, all the piezoelectric elements of Example 3-1 showed good results. The results are shown in Table 2.
  • a piezoelectric element of Example 3-2 was manufactured in the same manner as the piezoelectric element of Example 3 except that the thickness of the sintered metal was 2.1 ⁇ m and the thickness of the piezoelectric ceramic sheet was 15.0 ⁇ m.
  • Polarization treatment was performed by applying a voltage of 5 kV / mm to the piezoelectric element of Example 3-2. Thereafter, using a SHIMAZU micro-autograph MST-I, the distance between the fulcrums was set to 4 mm, and a three-point bending force of 0.1 N or more was repeatedly applied. The charge generated thereby was measured with an electrometer 6514 manufactured by KEITHLEY. The result is shown in FIG. As shown in FIG. 17, it was confirmed that charges generated by piezoelectric strain were generated in the piezoelectric element of Example 3-2.
  • the notation “A” in the evaluation column of Tables 1 and 2 indicates that the evaluation is good, and the notation “B” indicates that the evaluation is not good.
  • the piezoelectric element of the embodiment can be used for, for example, a small and low-profile piezoelectric actuator used in a scanner, a camera module, a wearable device, or the like, or various piezoelectric sensors.
  • 1 sintered metal 1a base metal powder, 2 piezoelectric ceramic, 2a piezoelectric ceramic powder, 3 external electrode, 3a external electrode powder, 11 first internal electrode, 11a first internal electrode powder, 12 second internal electrode, 12a 2nd internal electrode powder, 21 1st side surface, 22 2nd side surface, 31 1st connection electrode, 32 2nd connection electrode, 41 base material, 101 sintered metal, 101a base metal powder sheet, 102 piezoelectric ceramic , 102a piezoelectric ceramic powder, 103 external electrode, 111 internal electrode, 111a internal electrode powder.

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Abstract

　A piezoelectric element is provided with a sintered metal (1) that contains a base metal, and a piezoelectric ceramic (2) that is provided integrally with the sintered metal (1). The piezoelectric ceramic (2) contains a Perovskite compound as a principal substance. The principal substance contains niobium, an alkali metal, and oxygen. The principal substance content in relation to the total molar amount of all substances contained in the piezoelectric ceramic (2) is 90% (molar) or above.

Description

圧電素子、圧電素子の製造方法、および圧電素子を備える圧電振動子Piezoelectric element, method for manufacturing piezoelectric element, and piezoelectric vibrator including piezoelectric element
　本発明は、圧電素子、圧電素子の製造方法、および圧電素子を備える圧電振動子に関する。 The present invention relates to a piezoelectric element, a method for manufacturing the piezoelectric element, and a piezoelectric vibrator including the piezoelectric element.
　近年、ユニモルフ型圧電アクチュエータおよびバイモルフ型アクチュエータ等の圧電セラミックを用いた圧電素子は、たとえば圧電スピーカやセンサー等の各種の圧電振動子に広く使用されている。 In recent years, piezoelectric elements using piezoelectric ceramics such as unimorph piezoelectric actuators and bimorph actuators are widely used in various piezoelectric vibrators such as piezoelectric speakers and sensors.
　たとえば特開昭６３－１７５７４号公報（特許文献１）には、炭素を含むＳＫ鋼の金属板からなる中間板の中央部の両側に圧電セラミック素子が有機系接着剤により接合されてなる圧電バイモルフ素子が開示されている（特許文献１の第３頁の右下欄～第４頁の左上欄参照）。 For example, Japanese Patent Laid-Open No. 63-17574 (Patent Document 1) discloses a piezoelectric bimorph in which a piezoelectric ceramic element is bonded to both sides of an intermediate plate made of a metal plate of SK steel containing carbon by an organic adhesive. An element is disclosed (see the lower right column on page 3 to the upper left column on page 4 of Patent Document 1).
　また、たとえば特開２０１３－２１９２５０号公報（特許文献２）には、圧電体ペーストを金属板の少なくとも一方の主面に塗布し、その後、非酸化性雰囲気で焼成することによって、超薄型で変位量の大きなユニモルフ型およびバイモルフ型の圧電セラミック電子部品を得る方法が開示されている（特許文献２の段落［００１３］参照）。 Further, for example, in Japanese Patent Application Laid-Open No. 2013-219250 (Patent Document 2), a piezoelectric paste is applied to at least one main surface of a metal plate, and then fired in a non-oxidizing atmosphere, so that it is ultrathin. A method for obtaining a unimorph-type and bimorph-type piezoelectric ceramic electronic component having a large displacement is disclosed (see paragraph [0013] of Patent Document 2).
特開昭６３－１７５７４号公報JP-A 63-17574 特開２０１３－２１９２５０号公報JP 2013-219250 A
　しかしながら、特許文献１に記載の圧電バイモルフ素子は、中間板の両側の表面にそれぞれ圧電セラミック素子を有機系接着剤により貼り合わせて作製されているため、圧電セラミック素子の薄型化に限界があった。すなわち、中間板に圧電セラミック素子を貼り合わせるためには、焼結したセラミックからなる圧電セラミック素子を切断したり、中間板に貼り合わせたりする工程が必要となるが、このような工程を行うためには圧電セラミック素子の厚さは少なくとも１００μｍ程度必要となる。これは、圧電セラミック素子の厚さが１００μｍよりも薄くなると、たとえば圧電セラミック素子を切断する際、または圧電セラミック素子を加圧して中間板に貼り合わせる際等において、圧電セラミック素子に微小クラックが生じ、圧電セラミック素子の破損につながるためである。 However, since the piezoelectric bimorph element described in Patent Document 1 is manufactured by bonding piezoelectric ceramic elements to the surfaces on both sides of the intermediate plate with an organic adhesive, there is a limit to thinning the piezoelectric ceramic elements. . That is, in order to bond the piezoelectric ceramic element to the intermediate plate, it is necessary to cut the piezoelectric ceramic element made of sintered ceramic or to bond the piezoelectric ceramic element to the intermediate plate. In this case, the thickness of the piezoelectric ceramic element needs to be at least about 100 μm. This is because when the thickness of the piezoelectric ceramic element is less than 100 μm, for example, when the piezoelectric ceramic element is cut or when the piezoelectric ceramic element is pressed and bonded to the intermediate plate, a micro crack is generated in the piezoelectric ceramic element. This is because the piezoelectric ceramic element is damaged.
　また、特許文献２に記載の方法においては、金属板の線熱膨張係数と金属板上に形成される圧電体の線熱膨張係数とが異なるため、圧電体ペーストの焼成時に圧電体に割れが発生したり、圧電体ペーストの焼成によって圧電体を形成することができたとしても、その冷却時に圧電体が金属板から剥がれたりするという問題があった。 In the method described in Patent Document 2, the linear thermal expansion coefficient of the metal plate and the linear thermal expansion coefficient of the piezoelectric body formed on the metal plate are different, so that the piezoelectric body is not cracked when the piezoelectric paste is fired. Even when the piezoelectric material is generated or the piezoelectric material can be formed by firing the piezoelectric paste, there is a problem that the piezoelectric material is peeled off from the metal plate during the cooling.
　上記の事情に鑑みて、本発明は、圧電セラミックにおける微小クラックおよび剥がれの発生を抑制することを目的としている。 In view of the above circumstances, an object of the present invention is to suppress the occurrence of microcracks and peeling in a piezoelectric ceramic.
　本発明に係る圧電素子は、卑金属を含む焼結金属と、焼結金属と一体に設けられた圧電セラミックとを備え、圧電セラミックは、ペロブスカイト型化合物を主要物質として含み、主要物質は、ニオブと、アルカリ金属と、酸素とを含み、圧電セラミックに含まれる全物質の総モル量に対する主要物質の含有量が９０モル％以上である圧電素子である。 A piezoelectric element according to the present invention includes a sintered metal including a base metal and a piezoelectric ceramic provided integrally with the sintered metal, and the piezoelectric ceramic includes a perovskite type compound as a main substance, and the main substance is niobium. In the piezoelectric element, the content of the main substance is 90 mol% or more with respect to the total molar quantity of all substances contained in the piezoelectric ceramic, including alkali metal and oxygen.
　圧電素子は、焼結金属と対向して圧電セラミック上に設けられた外部電極をさらに備えていてもよく、外部電極は、圧電セラミックと一体に設けられていることが好ましい。 The piezoelectric element may further include an external electrode provided on the piezoelectric ceramic so as to face the sintered metal, and the external electrode is preferably provided integrally with the piezoelectric ceramic.
　圧電セラミックは、一方主面と、他方主面とを有し、焼結金属は、圧電セラミックを挟み込むように圧電セラミックの一方主面及び他方主面に設けられていることが好ましい。 The piezoelectric ceramic preferably has one main surface and the other main surface, and the sintered metal is preferably provided on one main surface and the other main surface of the piezoelectric ceramic so as to sandwich the piezoelectric ceramic.
　圧電セラミックの厚みは１００μｍ以下であることが好ましい。
　焼結金属の厚みは１．７μｍ以上５．１μｍ以下であることが好ましい。 The thickness of the piezoelectric ceramic is preferably 100 μm or less.
The thickness of the sintered metal is preferably 1.7 μm or more and 5.1 μm or less.
　圧電素子は、圧電セラミックの内部に設けられた内部電極をさらに備えていてもよく、内部電極は、圧電セラミックと一体に設けられていることが好ましい。 The piezoelectric element may further include an internal electrode provided inside the piezoelectric ceramic, and the internal electrode is preferably provided integrally with the piezoelectric ceramic.
　内部電極は、第１の内部電極と、第２の内部電極とを含み、第１の内部電極は、圧電セラミックの第１の側面から焼結金属と向かい合うようにして延在し、圧電セラミックの第２の側面まで達しないように設けられており、第２の内部電極は、圧電セラミックの第２の側面から焼結金属と向かい合うようにして延在し、圧電セラミックの第１の側面まで達しないように設けられており、第１の内部電極と第２の内部電極とは間隔を空けて向かい合うようにして設けられていてもよい。 The internal electrode includes a first internal electrode and a second internal electrode. The first internal electrode extends from the first side surface of the piezoelectric ceramic so as to face the sintered metal, and The second internal electrode extends from the second side surface of the piezoelectric ceramic so as to face the sintered metal, and reaches the first side surface of the piezoelectric ceramic. The first internal electrode and the second internal electrode may be provided so as to face each other with a space therebetween.
　圧電素子は、圧電セラミックの第１の側面に設けられた第１の接続電極と、圧電セラミックの第２の側面に設けられた第２の接続電極とを備え、第１の接続電極は、第１の内部電極と焼結金属とを電気的に接続しており、第２の接続電極は、第２の内部電極と外部電極とを電気的に接続していてもよい。 The piezoelectric element includes a first connection electrode provided on the first side surface of the piezoelectric ceramic, and a second connection electrode provided on the second side surface of the piezoelectric ceramic. One internal electrode and the sintered metal may be electrically connected, and the second connection electrode may electrically connect the second internal electrode and the external electrode.
　卑金属は、ニッケル、銅、およびアルミニウムからなる群から選択された少なくとも１種を含むことが好ましい。 The base metal preferably contains at least one selected from the group consisting of nickel, copper, and aluminum.
　本発明に係る圧電素子の製造方法は、卑金属を含む焼結金属と、焼結金属と一体に設けられた圧電セラミックとを備え、圧電セラミックは、ペロブスカイト型化合物を主要物質として含み、主要物質は、ニオブと、アルカリ金属と、酸素とを含み、圧電セラミックに含まれる全物質の総モル量に対する主要物質の含有量が９０モル％以上である圧電素子の製造方法であって、圧電セラミック粉末と卑金属粉末とを重ね合わせる第１の工程と、重ね合わされた圧電セラミック粉末と卑金属粉末とを共焼結する第２の工程とを含む圧電素子の製造方法である。 A method for manufacturing a piezoelectric element according to the present invention includes a sintered metal including a base metal and a piezoelectric ceramic provided integrally with the sintered metal, the piezoelectric ceramic including a perovskite type compound as a main material, A method for producing a piezoelectric element comprising niobium, an alkali metal, and oxygen, wherein the content of the main substance is 90 mol% or more with respect to the total molar quantity of all substances contained in the piezoelectric ceramic, A piezoelectric element manufacturing method including a first step of superimposing a base metal powder and a second step of co-sintering the superposed piezoelectric ceramic powder and the base metal powder.
　本発明に係る圧電素子の製造方法における第１の工程は、複数の圧電セラミック粉末の間に内部電極粉末を重ね合わせる工程をさらに含み、第２の工程において、重ね合わされた圧電セラミック粉末と卑金属粉末と内部電極粉末とを共焼結してもよい。 The first step in the method for manufacturing a piezoelectric element according to the present invention further includes a step of superposing internal electrode powders between a plurality of piezoelectric ceramic powders, and the piezoelectric ceramic powder and base metal powder superposed in the second step. And the internal electrode powder may be co-sintered.
　本発明に係る圧電素子の製造方法における第２の工程は、重ね合わされた圧電セラミック粉末と卑金属粉末とをＺｒＯ2、Ａｌ2Ｏ3およびＳｉＯ2からなる群から選択された少なくとも１つ以上含む物質を主要物質とするセラミックで挟み、共焼結することが好ましい。 The second step in the method for manufacturing a piezoelectric element according to the present invention is a substance containing at least one or more piezoelectric ceramic powder and base metal powder selected from the group consisting of ZrO 2 , Al 2 O 3 and SiO 2. It is preferable to sandwich the ceramics with the main material and co-sinter.
　本発明に係る圧電素子の製造方法における第２の工程は、卑金属と卑金属の酸化物とが平衡となる酸素分圧の１０００倍以下の酸素分圧の雰囲気下で行われることが好ましい。 The second step in the method for manufacturing a piezoelectric element according to the present invention is preferably performed in an atmosphere having an oxygen partial pressure equal to or lower than 1000 times the oxygen partial pressure at which the base metal and the base metal oxide are in equilibrium.
　本発明に係る圧電振動子は、上記の圧電素子を備える。 A piezoelectric vibrator according to the present invention includes the above-described piezoelectric element.
　本発明によれば、圧電セラミックにかかる負荷を抑制することができるため、圧電セラミックにおける微小クラックおよび剥がれの発生を抑制することができる。 According to the present invention, since the load applied to the piezoelectric ceramic can be suppressed, the occurrence of microcracks and peeling in the piezoelectric ceramic can be suppressed.
実施の形態１の圧電素子の模式的な断面図である。2 is a schematic cross-sectional view of the piezoelectric element according to Embodiment 1. FIG. 実施の形態１の圧電素子の製造方法の一例を図解するための模式的な断面図である。FIG. 3 is a schematic cross-sectional view for illustrating an example of a method for manufacturing the piezoelectric element according to the first embodiment. 実施の形態１の圧電素子の製造方法の一例を図解するための模式的な断面図である。FIG. 3 is a schematic cross-sectional view for illustrating an example of a method for manufacturing the piezoelectric element according to the first embodiment. 実施の形態１の圧電素子の製造方法の一例を図解するための模式的な断面図である。FIG. 3 is a schematic cross-sectional view for illustrating an example of a method for manufacturing the piezoelectric element according to the first embodiment. 実施の形態１の圧電素子の製造方法の一例を図解するための模式的な断面図である。FIG. 3 is a schematic cross-sectional view for illustrating an example of a method for manufacturing the piezoelectric element according to the first embodiment. Ｎｉ－ＮｉＯ平衡酸素分圧の対数と温度との関係を示す図である。It is a figure which shows the relationship between the logarithm of Ni-NiO equilibrium oxygen partial pressure, and temperature. Ｃｕ－Ｃｕ2Ｏ平衡酸素分圧の対数と温度との関係を示す図である。It is a diagram showing the relationship between the logarithm and the temperature of the Cu-Cu 2 O average oxygen partial pressure. 実施の形態２の圧電素子の模式的な断面図である。6 is a schematic cross-sectional view of a piezoelectric element according to Embodiment 2. FIG. 実施の形態２の圧電素子の製造方法の一例を図解するための模式的な断面図である。FIG. 10 is a schematic cross-sectional view for illustrating an example of a method for manufacturing the piezoelectric element according to the second embodiment. 実施の形態２の圧電素子の製造方法の他の一例を図解するための模式的な断面図である。FIG. 10 is a schematic cross-sectional view for illustrating another example of the method for manufacturing the piezoelectric element according to the second embodiment. 実施例１の共焼結前の積層体の模式的な断面図である。2 is a schematic cross-sectional view of a laminated body before co-sintering in Example 1. FIG. 実施例１の圧電素子の断面の走査型電子顕微鏡による観察結果である。It is an observation result by the scanning electron microscope of the cross section of the piezoelectric element of Example 1. FIG. 実施例１の圧電素子の焼結金属の表面の走査型電子顕微鏡による観察結果である。It is an observation result by the scanning electron microscope of the surface of the sintered metal of the piezoelectric element of Example 1. FIG. 比較例の共焼結前の積層体の模式的な断面図である。It is typical sectional drawing of the laminated body before the co-sintering of a comparative example. 比較例の圧電素子の圧延加工されたＮｉ板の表面の走査型電子顕微鏡による観察結果である。It is an observation result by the scanning electron microscope of the surface of the Ni plate by which the rolling process of the piezoelectric element of the comparative example was carried out. 実施の形態１の変形例における圧電素子の模式的な断面図である。FIG. 6 is a schematic cross-sectional view of a piezoelectric element in a modification of the first embodiment. 実施例３－２の圧電素子に３点曲げ力を繰り返し加えた際の時間に対する発生電荷を示す図である。It is a figure which shows the electric charge generated with respect to time when a three-point bending force is repeatedly applied to the piezoelectric element of Example 3-2.
　以下、本発明の一例である実施の形態について説明する。なお、実施の形態の説明に用いられる図面において、同一の参照符号は、同一部分または相当部分を表わすものとする。 Hereinafter, an embodiment which is an example of the present invention will be described. Note that in the drawings used to describe the embodiments, the same reference numerals represent the same or corresponding parts.
　［実施の形態１］
　＜圧電素子の構造＞
　図１に、実施の形態１の圧電素子の模式的な断面図を示す。図１に示す実施の形態１の圧電素子は、たとえば平板状である。圧電素子は、卑金属を含む焼結金属１と、焼結金属１上に焼結金属１と一体に設けられた圧電セラミック２と、圧電セラミック２上に設けられた外部電極３とを備えている。ここで、焼結金属１および外部電極３は、それぞれ、圧電セラミック２の互いに向かい合う下面および上面に設けられており、焼結金属１と外部電極３とは圧電セラミック２を介して互いに向かい合っている。 [Embodiment 1]
<Structure of piezoelectric element>
FIG. 1 shows a schematic cross-sectional view of the piezoelectric element of the first embodiment. The piezoelectric element according to Embodiment 1 shown in FIG. 1 has, for example, a flat plate shape. The piezoelectric element includes a sintered metal 1 including a base metal, a piezoelectric ceramic 2 provided integrally with the sintered metal 1 on the sintered metal 1, and an external electrode 3 provided on the piezoelectric ceramic 2. . Here, the sintered metal 1 and the external electrode 3 are provided on the lower surface and the upper surface of the piezoelectric ceramic 2 that face each other, and the sintered metal 1 and the external electrode 3 face each other through the piezoelectric ceramic 2. .
　卑金属を含む焼結金属１は、卑金属の結晶粒の複数が互いに接して固着している構造を有している。ここで、卑金属は、金（Ａｕ）、銀（Ａｇ）、白金（Ｐｔ）、パラジウム（Ｐｄ）、ロジウム（Ｒｈ）、イリジウム（Ｉｒ）、ルテニウム（Ｒｕ）およびオスミウム（Ｏｓ）以外の金属である。焼結金属とは、圧電セラミックの焼結前には金属粉末状態であるが、圧電セラミックと同時に共焼結されて薄板状金属となったものを指す。なお、内部電極は広義には焼結金属に含まれるが、ここでは、主面の両側に圧電セラミックが存在する焼結金属を「内部電極」と定義し、主面の片側にのみ圧電セラミックが存在する焼結金属を「焼結金属」と定義する。 The sintered metal 1 containing a base metal has a structure in which a plurality of base metal crystal grains are fixed in contact with each other. Here, the base metal is a metal other than gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os). . Sintered metal refers to a metal powder that has been in a metal powder state prior to the sintering of the piezoelectric ceramic, but has been co-sintered simultaneously with the piezoelectric ceramic to form a thin plate metal. The internal electrode is included in the sintered metal in a broad sense, but here, the sintered metal in which the piezoelectric ceramic exists on both sides of the main surface is defined as “internal electrode”, and the piezoelectric ceramic is formed only on one side of the main surface. The existing sintered metal is defined as “sintered metal”.
　焼結金属１を低コストで形成するためには、焼結金属１に用いられる卑金属としては、ニッケル（Ｎｉ）、銅（Ｃｕ）、およびアルミニウム（Ａｌ）からなる群から選択された少なくとも１種を含む金属を用いることが好ましく、ＮｉおよびＣｕの少なくとも一方を含む金属を用いることがより好ましく、Ｎｉを用いることがさらに好ましい。 In order to form the sintered metal 1 at low cost, the base metal used for the sintered metal 1 is at least one selected from the group consisting of nickel (Ni), copper (Cu), and aluminum (Al). It is preferable to use a metal containing Ni, more preferably a metal containing at least one of Ni and Cu, and even more preferably Ni.
　圧電セラミック２は、ペロブスカイト型化合物を主要物質として含んでおり、主要物質は、ニオブ（Ｎｂ）と、アルカリ金属と、酸素（Ｏ）とを含んでおり、圧電セラミック２に含まれる全物質の総モル量に対する主要物質の含有量は９０モル％以上となっている。 The piezoelectric ceramic 2 contains a perovskite type compound as a main substance, and the main substance contains niobium (Nb), an alkali metal, and oxygen (O), and the total of all the substances contained in the piezoelectric ceramic 2 is included. The content of the main substance with respect to the molar amount is 90 mol% or more.
　圧電セラミック中における主要物質としてのペロブスカイト型化合物の存在および含有量は、Ｘ線回折法により求めることができる。すなわち、ペロブスカイト型化合物の存在は、Ｘ線回折法により得られたＸ線回折パターンの特定の位置にＸ線回折ピークが現れることによって確認することができる。たとえば、Ａｃｔａ　Ｃｒｙｓｔａｌｌｏｇｒ.,　Ｓｅｃ.　Ａ,　３４　３０９　（１９７８）に（Ｎａ0.35Ｋ0.65）ＮｂＯ3の粉末Ｘ線回折データが記載されている。このデータと比較し、各ピークの強度比、面間隔ｄに対するピーク位置が類似であれば、アルカリ金属とニオブを含むペロブスカイト型化合物と判断できる。また、ペロブスカイト型化合物の含有量とＸ線回折ピーク強度の大きさとは比例関係にあるため、ペロブスカイト型化合物とそれ以外の物質との含有量が既知の試料を用いてペロブスカイト型化合物の含有量とＸ線回折ピーク強度の大きさとの関係を示す検量線を作成することができる。その検量線に基づき、圧電セラミック中における主要物質としてのペロブスカイト型化合物の含有量を求めることができる。さらに、圧電セラミックに含まれる各構成元素の含有量（重量％）は、誘導結合高周波プラズマ分光分析（ＩＣＰ分光分析）により求めることができる。そして、Ｘ線回折法によって圧電セラミックがどのような結晶構造を有しているかがわかるため、圧電セラミックの結晶構造のどのサイトにどの構成元素の原子が位置しているかがわかる。具体的には、上述の（Ｎａ0.35Ｋ0.65）ＮｂＯ3の回折データと比較し、類似していれば、アルカリ金属とニオブと酸素を含むペロブスカイト化合物と判断できる。これにより、圧電セラミックに含まれる全物質の総モル量に対して、Ｎｂとアルカリ金属とＯとを含むペロブスカイト型化合物が主要物質として９０モル％以上含まれていることを確認することができる。 The presence and content of the perovskite type compound as the main substance in the piezoelectric ceramic can be determined by an X-ray diffraction method. That is, the presence of the perovskite type compound can be confirmed by the appearance of an X-ray diffraction peak at a specific position in the X-ray diffraction pattern obtained by the X-ray diffraction method. For example, Acta Crystallogr., Sec. A, 34 309 (1978) describes powder X-ray diffraction data of (Na 0.35 K 0.65 ) NbO 3 . When compared with this data, if the intensity ratio of each peak and the peak position with respect to the interplanar spacing d are similar, it can be determined as a perovskite type compound containing alkali metal and niobium. In addition, since the content of the perovskite compound and the magnitude of the X-ray diffraction peak intensity are in a proportional relationship, the content of the perovskite compound and the content of the perovskite compound and the other substances are known using a known sample. A calibration curve showing the relationship with the magnitude of the X-ray diffraction peak intensity can be created. Based on the calibration curve, the content of the perovskite type compound as the main substance in the piezoelectric ceramic can be determined. Further, the content (% by weight) of each constituent element contained in the piezoelectric ceramic can be obtained by inductively coupled high-frequency plasma spectroscopic analysis (ICP spectroscopic analysis). Since the crystal structure of the piezoelectric ceramic is found by the X-ray diffraction method, it is possible to know which constituent element atom is located at which site of the crystal structure of the piezoelectric ceramic. Specifically, it can be judged as a perovskite compound containing an alkali metal, niobium and oxygen if it is similar to the diffraction data of (Na 0.35 K 0.65 ) NbO 3 described above. Thereby, it can be confirmed that 90 mol% or more of the perovskite type compound containing Nb, alkali metal and O is contained as a main substance with respect to the total molar amount of all the substances contained in the piezoelectric ceramic.
　なお、上記の主要物質としてのペロブスカイト型化合物には、タンタル（Ｔａ）が含まれていてもよい。 The perovskite type compound as the main substance may contain tantalum (Ta).
　また、主要物質（ペロブスカイト型化合物）以外の副物質としては、たとえば、バリウム（Ｂａ）、ストロンチウム（Ｓｒ）、カルシウム（Ｃａ）、ジルコニウム（Ｚｒ）、チタン（Ｔｉ）、錫（Ｓｎ）、マンガン（Ｍｎ）、Ｎｉ、スカンジウム（Ｓｃ）、イットリウム（Ｙ）、ランタン（Ｌａ）、セリウム（Ｃｅ）、プラセオジム（Ｐｒ）、ネオジム（Ｎｄ）、プロメチウム（Ｐｍ）、サマリウム（Ｓｍ）、ユウロピウム（Ｅｕ）、ガドリニウム（Ｇｄ）、テルビウム（Ｔｂ）、ジスプロシウム（Ｄｙ）、ホルミウム（Ｈｏ）、エルビウム（Ｅｒ）、ツリウム（Ｔｍ）、イッテルビウム（Ｙｂ）およびルテチウム（Ｌｕ）からなる群から選択された少なくとも１種を挙げることができる。 In addition, examples of auxiliary substances other than the main substance (perovskite type compound) include, for example, barium (Ba), strontium (Sr), calcium (Ca), zirconium (Zr), titanium (Ti), tin (Sn), manganese ( Mn), Ni, scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), At least one selected from the group consisting of gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) Can be mentioned.
　圧電セラミック２は、焼結金属１と一体に設けられている。すなわち、焼結金属１と圧電セラミック２との接合界面において、焼結金属１に含まれる卑金属の結晶粒と、圧電セラミック２に含まれる圧電セラミックの結晶粒とが接して固着していることによって焼結金属１と圧電セラミック２とが一体となって、焼結金属１と圧電セラミック２とが接合されている。焼結金属は、圧電セラミックの焼成前には卑金属粉末として存在するが、圧電セラミックと同時に共焼結されて卑金属粉末が焼結したものである。 The piezoelectric ceramic 2 is provided integrally with the sintered metal 1. That is, at the bonding interface between the sintered metal 1 and the piezoelectric ceramic 2, the base metal crystal grains contained in the sintered metal 1 and the piezoelectric ceramic crystal grains contained in the piezoelectric ceramic 2 are in contact and fixed together. The sintered metal 1 and the piezoelectric ceramic 2 are integrated, and the sintered metal 1 and the piezoelectric ceramic 2 are joined. The sintered metal exists as a base metal powder before firing the piezoelectric ceramic, but is sintered together with the piezoelectric ceramic and the base metal powder is sintered.
　外部電極３は、たとえば卑金属等の導電性材料を含み、圧電セラミック２に外部から電流を注入、または圧電セラミック２から外部に電流を取り出すことができる部材であれば特に限定されない。外部電極は、圧電セラミックの焼結後に、たとえばスパッタ法、蒸着法、または金属ペーストの焼き付け法などによって形成される。 The external electrode 3 includes, for example, a conductive material such as a base metal, and is not particularly limited as long as it is a member that can inject current from the outside into the piezoelectric ceramic 2 or take out current from the piezoelectric ceramic 2. The external electrode is formed, for example, by sputtering, vapor deposition, or metal paste baking after sintering the piezoelectric ceramic.
　また、外部電極３は、圧電セラミック２と一体に設けられていることが好ましい。すなわち、圧電素子に形成されている全ての電極が焼結金属であってもよい。圧電セラミック２と外部電極３とが一体に設けられている場合には、圧電セラミック２と外部電極３との接合界面において、圧電セラミック２に含まれる圧電セラミックの結晶粒と、外部電極３に含まれる卑金属等の導電性材料の結晶粒とが接して固着していることによって圧電セラミック２と外部電極３との接合をより強固なものとすることができるため、圧電セラミック２からの外部電極３の剥がれの発生をより効果的に抑制することができる。 The external electrode 3 is preferably provided integrally with the piezoelectric ceramic 2. That is, all the electrodes formed on the piezoelectric element may be a sintered metal. When the piezoelectric ceramic 2 and the external electrode 3 are provided integrally, the crystal grains of the piezoelectric ceramic included in the piezoelectric ceramic 2 and the external electrode 3 are included at the bonding interface between the piezoelectric ceramic 2 and the external electrode 3. The bonding between the piezoelectric ceramic 2 and the external electrode 3 can be made stronger by the contact and fixing with the crystal grains of the conductive material such as the base metal, so that the external electrode 3 from the piezoelectric ceramic 2 can be made stronger. The occurrence of peeling can be more effectively suppressed.
　＜圧電素子の製造方法＞
　以下、図２～図５の模式的断面図を参照して、実施の形態１の圧電素子の製造方法の一例について説明する。まず、図２および図３に示すように、圧電セラミック粉末２ａおよび卑金属粉末１ａを用意する。 <Method for manufacturing piezoelectric element>
Hereinafter, an example of a method of manufacturing the piezoelectric element according to the first embodiment will be described with reference to schematic cross-sectional views of FIGS. First, as shown in FIGS. 2 and 3, a piezoelectric ceramic powder 2a and a base metal powder 1a are prepared.
　圧電セラミック粉末２ａは、後述する共焼結によって、圧電セラミック２となる物質である。 The piezoelectric ceramic powder 2a is a substance that becomes the piezoelectric ceramic 2 by co-sintering described later.
　圧電セラミック粉末２ａは、たとえば、主要物質となるペロブスカイト型化合物の含有量が９０モル％以上となるように、少なくともＮｂの酸化物粉末とアルカリ金属の炭酸物粉末とを秤量した後に、これらを混合して圧電セラミック素原料粉末を作製し、これを仮焼した後に粉砕することによって得ることができる。圧電セラミック粉末２ａは、他の物質と組み合わされて、または他の物質と組み合わされないで、たとえば、シート状、テープ状またはペースト状等の粉末状以外の形態とされていてもよい。 Piezoelectric ceramic powder 2a is prepared by, for example, weighing at least Nb oxide powder and alkali metal carbonate powder so that the content of a perovskite type compound as a main substance is 90 mol% or more, and then mixing them. Then, a piezoelectric ceramic raw material powder is prepared, calcined and then pulverized. The piezoelectric ceramic powder 2a may be combined with other substances or not combined with other substances, and may be in a form other than powder, such as a sheet, a tape, or a paste.
　卑金属粉末１ａは、後述する共焼結によって、卑金属を含む焼結金属１となる物質である。卑金属粉末１ａも、他の物質と組み合わされて、または他の物質と組み合わされないで、たとえば、シート状、テープ状またはペースト状等の粉末状以外の形態とされていてもよいが、シート状またはテープ状であることで均一となり、圧電素子の厚みが薄い場合は卑金属粉末の焼結が均一となるため、圧電素子の破損がなくなる。そのため、卑金属粉末の形態はシート状またはテープ状であることがより好ましい。 The base metal powder 1a is a substance that becomes a sintered metal 1 containing a base metal by co-sintering described later. The base metal powder 1a may be combined with other substances or not combined with other substances, and may be in a form other than powder, such as a sheet, tape, or paste. The tape shape is uniform, and when the piezoelectric element is thin, the base metal powder is uniformly sintered, so that the piezoelectric element is not damaged. Therefore, the form of the base metal powder is more preferably a sheet shape or a tape shape.
　次に、図４に示すように、卑金属粉末１ａと圧電セラミック粉末２ａとを重ね合わせる。卑金属粉末１ａと圧電セラミック粉末２ａとを重ね合わせる方法は、特に限定されないが、たとえば、図示しないポリエチレンテレフタレート（ＰＥＴ）フィルム等の基材の表面上に、たとえば、シート状またはテープ状の卑金属粉末１ａを設置した後に、卑金属粉末１ａ上に、たとえば、シート状、テープ状またはペースト状の圧電セラミック粉末２ａを設置する方法等を用いることができる。 Next, as shown in FIG. 4, the base metal powder 1a and the piezoelectric ceramic powder 2a are overlaid. The method of superposing the base metal powder 1a and the piezoelectric ceramic powder 2a is not particularly limited. For example, a method of installing a sheet-like, tape-like, or paste-like piezoelectric ceramic powder 2a on the base metal powder 1a can be used.
　次に、卑金属粉末１ａと圧電セラミック粉末２ａとを重ね合わせた状態で共焼結を行うことによって、図５に示すように、焼結金属１と圧電セラミック２とが一体化する。卑金属粉末１ａと圧電セラミック粉末２ａとの共焼結においては以下の現象が進行すると考えられる。すなわち、卑金属粉末１ａと圧電セラミック粉末２ａとの界面において、卑金属粉末１ａに含まれる卑金属の粒子と圧電セラミック粉末２ａに含まれる圧電セラミックの粒子とが互いに接触して固着し、次第にその固着面積が増大していく。そして、これらの固着面積が増大した粒子の結合体が多数集まって凝集し、これらの粒子の結合体間の空孔が次第に減少して緻密化していく。これにより、図５に示す焼結金属１と圧電セラミック２との接合界面においては、焼結金属１に含まれる卑金属の結晶粒と、圧電セラミック２に含まれる圧電セラミックの結晶粒とが接して固着することにより焼結金属１と圧電セラミック２とが一体化するため、焼結金属１と圧電セラミック２との間の強固な接合強度が発現する。 Next, co-sintering is performed in a state where the base metal powder 1a and the piezoelectric ceramic powder 2a are overlapped, whereby the sintered metal 1 and the piezoelectric ceramic 2 are integrated as shown in FIG. It is considered that the following phenomenon proceeds in the co-sintering of the base metal powder 1a and the piezoelectric ceramic powder 2a. That is, at the interface between the base metal powder 1a and the piezoelectric ceramic powder 2a, the base metal particles contained in the base metal powder 1a and the piezoelectric ceramic particles contained in the piezoelectric ceramic powder 2a are fixed in contact with each other, and the fixing area gradually increases. It will increase. A large number of aggregates of particles having an increased fixed area gather and agglomerate, and pores between the aggregates of these particles gradually decrease and become dense. Thus, at the bonding interface between the sintered metal 1 and the piezoelectric ceramic 2 shown in FIG. 5, the base metal crystal grains contained in the sintered metal 1 and the piezoelectric ceramic crystal grains contained in the piezoelectric ceramic 2 are in contact with each other. Since the sintered metal 1 and the piezoelectric ceramic 2 are integrated by being fixed, a strong bonding strength between the sintered metal 1 and the piezoelectric ceramic 2 is exhibited.
　なお、圧電セラミック２および焼結金属１からなる圧電素子を形成する場合、あるいは内部電極を含んだ圧電セラミック２および焼結金属１からなる圧電素子を形成する場合には、これらの圧電素子をＺｒＯ2、Ａｌ2Ｏ3およびＳｉＯ2からなる群から選択された少なくとも１つ以上含む物質を主要物質とするセラミックで挟み、共焼結することが好ましい。セラミックは、緻密であっても、空隙が存在していてもよい。セラミックは板状であっても、塊状であっても、曲面を有していてもよい。このようにすることで、共焼結の際の意図しない変形を抑制することができる。 When a piezoelectric element made of the piezoelectric ceramic 2 and the sintered metal 1 is formed, or when a piezoelectric element made of the piezoelectric ceramic 2 including the internal electrode and the sintered metal 1 is formed, these piezoelectric elements are made of ZrO. 2 , It is preferable to sandwich and co-sinter a material containing at least one selected from the group consisting of Al 2 O 3 and SiO 2 as a main material. The ceramic may be dense or may have voids. The ceramic may be plate-shaped, massive, or curved. By doing in this way, the unintended deformation | transformation in the case of co-sintering can be suppressed.
　ここで、卑金属粉末１ａと圧電セラミック粉末２ａとの共焼結は、卑金属粉末１ａに含まれる卑金属（焼結金属１に含まれる卑金属）と当該卑金属の酸化物とが平衡となる酸素分圧の１０００倍以下の酸素分圧の雰囲気下で行われることが好ましい。卑金属と卑金属の酸化物との平衡酸素分圧よりも雰囲気の酸素分圧が高くなると卑金属の酸化が進行する傾向にあるが、卑金属の酸化は急激に進行するわけではないため、卑金属と卑金属の酸化物との平衡酸素分圧の１０００倍を共焼結雰囲気の酸素分圧の上限とした場合でも、卑金属の酸化を抑制しながら卑金属粉末１ａの焼結を進行させることができ、たとえばＮｉＯまたは酸化銅（Ｃｕ2Ｏ）等の卑金属の酸化物の含有を抑制して焼結金属１を形成することができる。共焼結時の雰囲気の酸素分圧は、たとえば、ジルコニア酸素濃度センサーを用いて測定した酸素濃度から算出することができる。 Here, the co-sintering of the base metal powder 1a and the piezoelectric ceramic powder 2a has an oxygen partial pressure at which the base metal contained in the base metal powder 1a (base metal contained in the sintered metal 1) and the oxide of the base metal are in equilibrium. It is preferable to carry out in an atmosphere having an oxygen partial pressure of 1000 times or less. When the oxygen partial pressure of the atmosphere is higher than the equilibrium oxygen partial pressure of the base metal and the base metal oxide, the base metal oxidation tends to proceed. However, the base metal oxidation does not proceed rapidly, so the base metal and base metal oxidation Even when the equilibrium oxygen partial pressure with the oxide is 1000 times the upper limit of the oxygen partial pressure of the co-sintering atmosphere, the sintering of the base metal powder 1a can proceed while suppressing the oxidation of the base metal, for example, NiO or The sintered metal 1 can be formed while suppressing the inclusion of base metal oxides such as copper oxide (Cu 2 O). The oxygen partial pressure in the atmosphere during co-sintering can be calculated from, for example, the oxygen concentration measured using a zirconia oxygen concentration sensor.
　なお、ジルコニア酸素濃度センサーは、基準ガス中の酸素濃度と、測定ガス中の酸素濃度との比によって決定される起電力が発生することがよく知られており、その起電力は、以下のネルンストの式によって求められる。 It is well known that the zirconia oxygen concentration sensor generates an electromotive force determined by the ratio of the oxygen concentration in the reference gas and the oxygen concentration in the measurement gas. It is calculated by the following formula.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　なお、上記のネルンストの式において、Ｅ：起電力（Ｖ）、Ｒ：気体定数（８．３１４５（Ｊ・ｍｏｌ-1・Ｋ-1））、Ｔ：絶対温度（Ｋ）、ｎ：反応に含まれる電子数、Ｆ：ファラデー定数（９．６４９×１０4（Ｃ・ｍｏｌ-1））、Ｐｒ：基準ガス中の酸素濃度（通常は大気）、Ｐｍ：測定ガス中の酸素濃度である。 In the above Nernst equation, E: electromotive force (V), R: gas constant (8.3145 (J · mol −1 · K −1 )), T: absolute temperature (K), n: reaction Number of electrons contained, F: Faraday constant (9.649 × 10 4 (C · mol −1 )), Pr: oxygen concentration in the reference gas (usually air), Pm: oxygen concentration in the measurement gas.
　図６に、ＮｉとＮｉＯとの平衡酸素分圧（Ｎｉ－ＮｉＯ平衡酸素分圧）の対数と温度との関係を示す。また、図７に、ＣｕとＣｕ2Ｏとの平衡酸素分圧（Ｃｕ－Ｃｕ2Ｏ平衡酸素分圧）の対数と温度との関係を示す。 FIG. 6 shows the relationship between the logarithm of the equilibrium oxygen partial pressure of Ni and NiO (Ni—NiO equilibrium oxygen partial pressure) and the temperature. FIG. 7 shows the relationship between the logarithm of the equilibrium oxygen partial pressure (Cu—Cu 2 O equilibrium oxygen partial pressure) of Cu and Cu 2 O and the temperature.
　金属と酸化物の平衡反応と、酸素分圧および温度との関係は熱力学的に解析でき、一般的にエリンガム図から理解できる。系が平衡状態にあるとき、たとえば２Ｎｉ＋Ｏ2 → ←２ＮｉＯの反応が平衡状態にあるとき、標準反応ギブスエネルギー△Ｇ0は、△Ｇ0＝－ＲＴｌｎＫの式で表すことができる。すなわち、２Ｎｉ＋Ｏ2 → ←２ＮｉＯの平衡反応の場合、ＮｉおよびＮｉＯは固体であるため、酸素分圧をＰＯ2とすると、ＰＯ2＝１／Ｋとなる。したがって、ｌｎＰＯ2＝△Ｇ0／ＲＴとかける。 The relationship between the equilibrium reaction between metal and oxide and the partial pressure of oxygen and temperature can be analyzed thermodynamically and can generally be understood from the Ellingham diagram. When the system is in an equilibrium state, for example, when the reaction of 2Ni + O 2 → ← 2NiO is in an equilibrium state, the standard reaction Gibbs energy ΔG 0 can be expressed by the equation: ΔG 0 = −RTlnK. That is, in the case of the equilibrium reaction of 2Ni + O 2 → ← 2NiO, Ni and NiO are solids. Therefore, when the oxygen partial pressure is PO 2 , PO 2 = 1 / K. Therefore, lnP O2 = ΔG 0 / RT.
　その後、図１に示すように、焼結金属１と向かい合うようにして圧電セラミック２上に外部電極３を形成することによって、実施の形態１の圧電素子を製造することができる。 Thereafter, as shown in FIG. 1, the external electrode 3 is formed on the piezoelectric ceramic 2 so as to face the sintered metal 1, whereby the piezoelectric element of the first embodiment can be manufactured.
　外部電極３は、既に共焼結が終了して一体化した焼結金属１と圧電セラミック２とにおいて、焼結金属１と対向する圧電セラミック２の面に形成する。外部電極３を形成する材料は導電性があればよく、たとえば銀、金、白金、ニッケル、または銅などである。外部電極３の形成方法も特に限定されるものではなく、たとえばスパッタ法、蒸着法、金属粉末を焼き付ける方法などがある。外部電極３は、焼結金属１と圧電セラミック２とを共焼結した後に、焼結金属１と対向する圧電セラミック２の面に、たとえばスパッタ法、蒸着法、または、金属粉若しくは金属粉ペーストを焼き付ける方法などで形成することができる。 The external electrode 3 is formed on the surface of the piezoelectric ceramic 2 facing the sintered metal 1 in the sintered metal 1 and the piezoelectric ceramic 2 which have already been co-sintered and integrated. The material for forming the external electrode 3 only needs to be electrically conductive, such as silver, gold, platinum, nickel, or copper. The method for forming the external electrode 3 is not particularly limited, and examples thereof include a sputtering method, a vapor deposition method, and a method for baking metal powder. After the sintered metal 1 and the piezoelectric ceramic 2 are co-sintered, the external electrode 3 is formed on the surface of the piezoelectric ceramic 2 facing the sintered metal 1 by, for example, sputtering, vapor deposition, or metal powder or metal powder paste. Can be formed by a method such as baking.
　＜作用効果＞
　実施の形態１においては、卑金属粉末１ａと圧電セラミック粉末２ａとの共焼結によって焼結金属１と圧電セラミック２とを形成しているため、従来の特許文献２のように、金属板と圧電体との線熱膨張係数差に起因する微小クラックの発生が抑制される。また、圧電セラミック２は、焼結金属１の卑金属と比べて線熱膨張係数が小さいため、共焼結後の冷却時には、圧電セラミック２は焼結金属１から圧縮応力を受けることになるが、焼結金属１と圧電セラミック２とは一体に形成され、その接合強度が高いことから、当該圧縮応力に起因する圧電セラミック２の剥がれも抑制することができる。 <Effect>
In the first embodiment, since the sintered metal 1 and the piezoelectric ceramic 2 are formed by co-sintering the base metal powder 1a and the piezoelectric ceramic powder 2a, the metal plate and the piezoelectric as in the conventional patent document 2 are formed. The generation of microcracks due to the difference in linear thermal expansion coefficient from the body is suppressed. Moreover, since the piezoelectric ceramic 2 has a smaller linear thermal expansion coefficient than the base metal of the sintered metal 1, the piezoelectric ceramic 2 receives a compressive stress from the sintered metal 1 during cooling after co-sintering. Since the sintered metal 1 and the piezoelectric ceramic 2 are integrally formed and have high bonding strength, peeling of the piezoelectric ceramic 2 due to the compressive stress can also be suppressed.
　以上の理由により、実施の形態１においては、圧電セラミック２における微小クラックおよび剥がれの発生を抑制することができる。 For the reasons described above, in the first embodiment, the occurrence of microcracks and peeling in the piezoelectric ceramic 2 can be suppressed.
　また、実施の形態１においては、従来の特許文献１のように、焼結金属１に圧電セラミック２を有機系接着剤で貼り合わせる工程必要がなく、有機系接着剤の材料コストを低減することができるとともに、工数減による製造コストも低減することができる。 Further, in the first embodiment, unlike the conventional patent document 1, there is no need to bond the piezoelectric ceramic 2 to the sintered metal 1 with an organic adhesive, thereby reducing the material cost of the organic adhesive. In addition, the manufacturing cost due to the reduction in the number of steps can be reduced.
　また、実施の形態１においては、卑金属粉末１ａと圧電セラミック粉末２ａとの共焼結によって焼結金属１と圧電セラミック２とを形成することができるため、従来の特許文献１と比べて焼結金属１および圧電セラミック２のそれぞれを薄く形成することができる。そのため、実施の形態１においては、圧電セラミック２の薄膜化（圧電セラミック２の厚さ：１００μｍ以下）によって、同一の大きさの電界で駆動させる場合の印加電圧を低くすることができ、印加電圧を上昇させるための回路が不要となるため、回路を簡略化することができ、ひいては製造コストの低減につながる。 In the first embodiment, the sintered metal 1 and the piezoelectric ceramic 2 can be formed by co-sintering the base metal powder 1a and the piezoelectric ceramic powder 2a. Each of the metal 1 and the piezoelectric ceramic 2 can be formed thin. Therefore, in the first embodiment, by applying a thin film of the piezoelectric ceramic 2 (thickness of the piezoelectric ceramic 2: 100 μm or less), it is possible to reduce the applied voltage when driven by the same electric field. Since a circuit for increasing the voltage is not necessary, the circuit can be simplified, which leads to a reduction in manufacturing cost.
　さらに、実施の形態１においては、従来の特許文献２と比べても少なくとも焼結金属１を薄く形成することができるため、焼結金属１および圧電セラミック２のそれぞれの薄型化により、従来の特許文献１および特許文献２と比べて、変位の大きな圧電素子とすることができる。なお、ロール間に複数回繰り返して通過させること等によって特許文献２の金属板を薄型化することもできるが、工数が増加するために製造コストが増加するとともに、薄型化した金属板はたとえばアルミニウム箔のようによれやすくなるため、取り扱いが困難となる。 Furthermore, in the first embodiment, since the sintered metal 1 can be formed at least thinner than the conventional patent document 2, each of the sintered metal 1 and the piezoelectric ceramic 2 can be made thinner. Compared with Document 1 and Patent Document 2, a piezoelectric element having a large displacement can be obtained. In addition, although the metal plate of patent document 2 can also be thinned by repeatedly passing between rolls etc., since a man-hour increases, manufacturing cost increases and the thinned metal plate is aluminum, for example Since it becomes easy to sag like foil, handling becomes difficult.
　また、実施の形態１においては、圧電素子の形状は平板状に限られるものではなく、たとえばロール状または波板状等の平板状以外の形状に形成されていてもよい。本発明は、このように圧電素子が平板状以外の形状の場合に、特に効果が大きくなる。 In the first embodiment, the shape of the piezoelectric element is not limited to a flat plate shape, and may be formed in a shape other than a flat plate shape such as a roll shape or a corrugated plate shape. The present invention is particularly effective when the piezoelectric element has a shape other than a flat plate shape.
　［実施の形態１の変形例］
　図１６に実施の形態１の変形例における圧電素子を示す。実施の形態１の変形例の圧電素子が実施の形態１の圧電素子と異なる点は、実施の形態１における外部電極３が焼結金属１であることである。圧電セラミック２は、一方主面と、他方主面とを有する板状に形成されている。焼結金属１は、圧電セラミック２を挟み込むように圧電セラミック２の一方主面及び他方主面に設けられている。このような場合であっても、実施の形態１と同様の効果を得ることができる。 [Modification of Embodiment 1]
FIG. 16 shows a piezoelectric element according to a modification of the first embodiment. The piezoelectric element of the modification of the first embodiment is different from the piezoelectric element of the first embodiment in that the external electrode 3 in the first embodiment is a sintered metal 1. The piezoelectric ceramic 2 is formed in a plate shape having one main surface and the other main surface. The sintered metal 1 is provided on one main surface and the other main surface of the piezoelectric ceramic 2 so as to sandwich the piezoelectric ceramic 2. Even in such a case, the same effect as in the first embodiment can be obtained.
　［実施の形態２］
　＜圧電素子の構造＞
　図８に、実施の形態２の圧電素子の模式的な断面図を示す。図８に示す実施の形態２の圧電素子は、焼結金属１と一体に形成されたたとえば略直方体形状の圧電セラミック２を有する。圧電セラミック２は内部に２本の第１の内部電極１１と２本の第２の内部電極１２とを備えており、圧電セラミック２の互いに向かい合う第１の側面２１および第２の側面２２にそれぞれ第１の接続電極３１および第２の接続電極３２を備えていることを特徴としている。なお、実施の形態２においては、第１の内部電極１１および第２の内部電極１２をそれぞれ２本ずつとしているが、第１の内部電極１１および第２の内部電極１２の本数は特に限定されるものではなく、１本ずつであってもよく、３本以上ずつであってもよい。また、第１の内部電極１１の本数と第２の内部電極１２の本数とは必ずしも同一である必要はなく、異なっていてもよい。なお、上述の略直方体形状には、直方体形状だけではなく、角に丸みを備える直方体形状、撓んだ面および／または湾曲した面を備える直方体形状も含まれる。 [Embodiment 2]
<Structure of piezoelectric element>
FIG. 8 is a schematic cross-sectional view of the piezoelectric element according to the second embodiment. The piezoelectric element according to the second embodiment shown in FIG. 8 has, for example, a substantially rectangular parallelepiped piezoelectric ceramic 2 formed integrally with the sintered metal 1. The piezoelectric ceramic 2 includes two first internal electrodes 11 and two second internal electrodes 12 therein, and the piezoelectric ceramic 2 has first and second side surfaces 21 and 22 facing each other. The first connection electrode 31 and the second connection electrode 32 are provided. In the second embodiment, the number of the first internal electrodes 11 and the number of the second internal electrodes 12 is two, but the number of the first internal electrodes 11 and the number of the second internal electrodes 12 is particularly limited. It may be one by one, or three or more. Further, the number of the first internal electrodes 11 and the number of the second internal electrodes 12 are not necessarily the same and may be different. The above-mentioned substantially rectangular parallelepiped shape includes not only a rectangular parallelepiped shape but also a rectangular parallelepiped shape having rounded corners, a rectangular parallelepiped shape having a curved surface and / or a curved surface.
　図８に示すように、第１の内部電極１１は、それぞれ、焼結金属１と向かい合うようにして第１の側面２１から第２の側面２２に向かって延在しており、第１の内部電極１１の一端は第１の側面２１内に位置しているが、他端は第２の側面２２まで到達していない。また、第２の内部電極１２は、それぞれ、焼結金属１と向かい合うようにして第２の側面２２から第１の側面２１に向かって延在しており、第２の内部電極１２の一端は第２の側面２２内に位置しているが、他端は第１の側面２１まで到達していない。また、第１の内部電極１１と第２の内部電極１２とは、圧電セラミック２の厚さ方向に沿って、１本ずつ交互に互いに間隔を空けて配置されている。 As shown in FIG. 8, the first internal electrodes 11 extend from the first side surface 21 toward the second side surface 22 so as to face the sintered metal 1, respectively. One end of the electrode 11 is located in the first side surface 21, but the other end does not reach the second side surface 22. Each of the second internal electrodes 12 extends from the second side surface 22 toward the first side surface 21 so as to face the sintered metal 1, and one end of the second internal electrode 12 is Although it is located in the second side surface 22, the other end does not reach the first side surface 21. Further, the first internal electrode 11 and the second internal electrode 12 are alternately arranged one by one along the thickness direction of the piezoelectric ceramic 2 and spaced apart from each other.
　また、圧電セラミック２の第１の側面２１に設けられた第１の接続電極３１の一端は、第１の側面２１内に位置する２本の第１の内部電極１１のそれぞれの一端と電気的に接続されており、第１の接続電極３１の他端は、焼結金属１と電気的に接続されている。これにより、第１の接続電極３１は、２本の第１の接続電極２１と焼結金属１とを電気的に接続している。 In addition, one end of the first connection electrode 31 provided on the first side surface 21 of the piezoelectric ceramic 2 is electrically connected to one end of each of the two first internal electrodes 11 located in the first side surface 21. The other end of the first connection electrode 31 is electrically connected to the sintered metal 1. Thereby, the first connection electrode 31 electrically connects the two first connection electrodes 21 and the sintered metal 1.
　また、第１の側面２１と対向する圧電セラミック２の第２の側面２２に設けられた第２の接続電極３２の一端は、第２の側面２２内に位置する２本の第２の内部電極１２のそれぞれの一端と電気的に接続されており、第２の接続電極３２の他端は、外部電極３と電気的に接続されている。これにより、第２の接続電極３２は、２本の第２の接続電極１２と外部電極３とを電気的に接続している。 In addition, one end of the second connection electrode 32 provided on the second side surface 22 of the piezoelectric ceramic 2 facing the first side surface 21 is two second internal electrodes located in the second side surface 22. The other end of the second connection electrode 32 is electrically connected to the external electrode 3. Thereby, the second connection electrode 32 electrically connects the two second connection electrodes 12 and the external electrode 3.
　＜圧電素子の製造方法＞
　以下、図９の模式的断面図を参照して、実施の形態２の圧電素子の製造方法の一例について説明する。まず、図９に示すように、ＰＥＴフィルム等の基材４１の表面上に卑金属粉末１ａを設置した後に、卑金属粉末１ａ上に、圧電セラミック粉末２ａ、第２の内部電極粉末１２ａ、圧電セラミック粉末２ａ、第１の内部電極粉末１１ａ、圧電セラミック粉末２ａ、第２の内部電極粉末１２ａ、圧電セラミック粉末２ａ、第１の内部電極粉末１１ａおよび圧電セラミック粉末２ａをこの順に設置する。 <Method for manufacturing piezoelectric element>
Hereinafter, an example of a method for manufacturing the piezoelectric element of the second embodiment will be described with reference to the schematic cross-sectional view of FIG. First, as shown in FIG. 9, after the base metal powder 1a is placed on the surface of the substrate 41 such as a PET film, the piezoelectric ceramic powder 2a, the second internal electrode powder 12a, and the piezoelectric ceramic powder are placed on the base metal powder 1a. 2a, first internal electrode powder 11a, piezoelectric ceramic powder 2a, second internal electrode powder 12a, piezoelectric ceramic powder 2a, first internal electrode powder 11a and piezoelectric ceramic powder 2a are placed in this order.
　ここで、第１の内部電極粉末１１ａは、後述の共焼結によって第１の内部電極１１となる物質であり、第２の内部電極粉末１２ａは、後述の共焼結によって第２の内部電極１２となる物質である。第１の内部電極粉末１１ａおよび第２の内部電極粉末１２ａとしては、たとえば、卑金属等の導電性材料を含むもの等を用いることができる。また、第１の内部電極粉末１１ａおよび第２の内部電極粉末１２ａも、それぞれ、他の物質と組み合わされて、または他の物質と組み合わされないで、たとえば、シート状、テープ状またはペースト状等の粉末状以外の形態とされていてもよい。 Here, the first internal electrode powder 11a is a substance that becomes the first internal electrode 11 by co-sintering described later, and the second internal electrode powder 12a is a second internal electrode by co-sintering described later. It is a substance that becomes 12. As the first internal electrode powder 11a and the second internal electrode powder 12a, for example, those containing a conductive material such as a base metal can be used. Further, the first internal electrode powder 11a and the second internal electrode powder 12a are also combined with other materials or not combined with other materials, for example, in the form of a sheet, tape, paste, etc. It may be in a form other than powder.
　次に、図９に示すように、基材４１の表面上に、卑金属粉末１ａ、圧電セラミック粉末２ａ、第２の内部電極粉末１２ａ、圧電セラミック粉末２ａ、第１の内部電極粉末１１ａ、圧電セラミック粉末２ａ、第２の内部電極粉末１２ａ、圧電セラミック粉末２ａ、第１の内部電極粉末１１ａおよび圧電セラミック粉末２ａをこの順に重ね合わせた状態で共焼結する。 Next, as shown in FIG. 9, the base metal powder 1a, the piezoelectric ceramic powder 2a, the second internal electrode powder 12a, the piezoelectric ceramic powder 2a, the first internal electrode powder 11a, and the piezoelectric ceramic are formed on the surface of the substrate 41. The powder 2a, the second internal electrode powder 12a, the piezoelectric ceramic powder 2a, the first internal electrode powder 11a, and the piezoelectric ceramic powder 2a are co-sintered in a state where they are superposed in this order.
　なお、内部電極を含む圧電セラミック２および焼結金属１からなる圧電素子を形成する場合には、重ね合わされた圧電セラミック粉末２ａと卑金属粉末１ａと第１の内部電極粉末１１ａと第２の内部電極粉末１２ａとをＺｒＯ2、Ａｌ2Ｏ3およびＳｉＯ2からなる群から選択された少なくとも１つ以上含む物質を主要物質とするセラミックで挟み、共焼結することが好ましい。上述のセラミックは、緻密であっても、空隙が存在していてもよい。また、上述のセラミックは板状であっても、塊状であっても、曲面を有していてもよい。このようにすることで、共焼結の際の意図しない変形を抑制することができる。 In addition, when forming the piezoelectric element which consists of the piezoelectric ceramic 2 containing an internal electrode, and the sintered metal 1, the laminated | stacked piezoelectric ceramic powder 2a, base metal powder 1a, 1st internal electrode powder 11a, and 2nd internal electrode It is preferable that the powder 12a is sandwiched between ceramics mainly composed of a substance containing at least one selected from the group consisting of ZrO 2 , Al 2 O 3 and SiO 2 and co-sintered. The ceramic described above may be dense or may have voids. Moreover, the above-mentioned ceramic may be plate-shaped, lump-shaped, or may have a curved surface. By doing in this way, the unintended deformation | transformation in the case of co-sintering can be suppressed.
　その後、図８に示すように、焼結金属１と向かい合うようにして圧電セラミック２上に外部電極３を形成するとともに、圧電セラミック２の第１の側面２１および第２の側面２２にそれぞれ第１の接続電極３１および第２の接続電極３２を形成することによって、実施の形態２の圧電素子を製造することができる。 After that, as shown in FIG. 8, the external electrode 3 is formed on the piezoelectric ceramic 2 so as to face the sintered metal 1, and the first side surface 21 and the second side surface 22 of the piezoelectric ceramic 2 are respectively first. By forming the connection electrode 31 and the second connection electrode 32, the piezoelectric element of the second embodiment can be manufactured.
　また、第１の接続電極３１および第２の接続電極３２の形成方法は特に限定されず、たとえば、外部電極３の形成後に、圧電セラミック２の第１の側面２１および第２の側面２２にそれぞれ金属を焼き付けること等によって、第１の接続電極３１および第２の接続電極３２を形成することができる。 Moreover, the formation method of the 1st connection electrode 31 and the 2nd connection electrode 32 is not specifically limited, For example, after formation of the external electrode 3, to the 1st side surface 21 and the 2nd side surface 22 of the piezoelectric ceramic 2, respectively. The first connection electrode 31 and the second connection electrode 32 can be formed by baking metal or the like.
　また、図１０の模式的断面図に示すように、基材４１の表面側から、圧電セラミック粉末２ａ、第１の内部電極粉末１１ａ、圧電セラミック粉末２ａ、第２の内部電極粉末１２ａ、圧電セラミック粉末２ａ、第１の内部電極粉末１１ａ、圧電セラミック粉末２ａ、第２の内部電極粉末１２ａ、圧電セラミック粉末２ａおよび卑金属粉末１ａをこの順に設置して、共焼結を行ってもよい。 Further, as shown in the schematic cross-sectional view of FIG. 10, from the surface side of the base material 41, the piezoelectric ceramic powder 2a, the first internal electrode powder 11a, the piezoelectric ceramic powder 2a, the second internal electrode powder 12a, and the piezoelectric ceramic. The powder 2a, the first internal electrode powder 11a, the piezoelectric ceramic powder 2a, the second internal electrode powder 12a, the piezoelectric ceramic powder 2a, and the base metal powder 1a may be placed in this order to perform co-sintering.
　また、外部電極３は、圧電セラミック２と一体に設けられていることが好ましい。すなわち、圧電素子に形成されているすべての電極が焼結金属および内部電極であってもよい。 The external electrode 3 is preferably provided integrally with the piezoelectric ceramic 2. That is, all the electrodes formed on the piezoelectric element may be a sintered metal and an internal electrode.
　＜作用効果＞
　実施の形態２においても、卑金属粉末１ａと圧電セラミック粉末２ａとの共焼結により、焼結金属１と圧電セラミック２とを一体に形成することができることから、実施の形態１と同様に、圧電セラミック２における微小クラックおよび剥がれの発生を抑制することができる。 <Effect>
Also in the second embodiment, the sintered metal 1 and the piezoelectric ceramic 2 can be integrally formed by co-sintering the base metal powder 1a and the piezoelectric ceramic powder 2a. The occurrence of microcracks and peeling in the ceramic 2 can be suppressed.
　実施の形態２における上記以外の説明は実施の形態１と同様であるため、その説明については繰り返さない。 Since the description other than the above in the second embodiment is the same as that in the first embodiment, the description thereof will not be repeated.
　［実験例１］
　まず、炭酸カリウム（Ｋ2ＣＯ3）、炭酸ナトリウム（Ｎａ2ＣＯ3）、炭酸リチウム（Ｌｉ2ＣＯ3）、酸化ニオブ（Ｎｂ2Ｏ5）、炭酸カルシウム（ＣａＣＯ3）、酸化ジルコニウム（ＺｒＯ2）、炭酸マンガン（ＭｎＣＯ3）および酸化イッテルビウム（Ｙｂ2Ｏ3）のそれぞれの粉末を用意した。 [Experiment 1]
First, potassium carbonate (K 2 CO 3 ), sodium carbonate (Na 2 CO 3 ), lithium carbonate (Li 2 CO 3 ), niobium oxide (Nb 2 O 5 ), calcium carbonate (CaCO 3 ), zirconium oxide (ZrO 2) ), Manganese carbonate (MnCO 3 ) and ytterbium oxide (Yb 2 O 3 ).
　次に、固溶体を形成するニオブ酸アルカリ金属化合物とジルコン酸カルシウムとの比率が９８：２となり、かつアルカリ金属（Ｋ、ＮａおよびＬｉ）のモル比がＫ：Ｎａ：Ｌｉ＝０．４５：０．５３：０．０２となるように、Ｋ2ＣＯ3、Ｎａ2ＣＯ3、Ｌｉ2ＣＯ3、Ｎｂ2Ｏ5、ＣａＣＯ3、およびＺｒＯ2のそれぞれの粉末を秤量した。また、上記固溶体１００モルに対して、ＺｒＯ2が３モル、ＭｎＯが５モル、Ｙｂ2Ｏ3が０．２５モルとなるように、ＺｒＯ2、ＭｎＣＯ3およびＹｂ2Ｏ3のそれぞれの粉末を秤量した。 Next, the ratio of alkali metal niobate to calcium zirconate forming a solid solution is 98: 2, and the molar ratio of alkali metals (K, Na and Li) is K: Na: Li = 0.45: 0. Each powder of K 2 CO 3 , Na 2 CO 3 , Li 2 CO 3 , Nb 2 O 5 , CaCO 3 , and ZrO 2 was weighed so that .53: 0.02. In addition, with respect to 100 mol of the above solid solution, each powder of ZrO 2 , MnCO 3 and Yb 2 O 3 is adjusted so that ZrO 2 is 3 mol, MnO is 5 mol, and Yb 2 O 3 is 0.25 mol. Weighed.
　次に、上記のように秤量した粉末を、ＰＳＺボールが内有されたポットミルに投入し、エタノールを溶媒にして約９０時間ポットミルを回転して、湿式で混合することにより圧電セラミック素原料粉末を得た。そして、得られた圧電セラミック素原料粉末を乾燥した後、９００℃の温度で仮焼し、その後、粉砕することによって、［１００｛０．９８（Ｋ0.45Ｎ0.53Ｌｉ0.02）ＮｂＯ3－０．０２ＣａＺｒＯ3｝＋３ＺｒＯ2＋５ＭｎＯ＋０．２５Ｙｂ2Ｏ3］の組成式で表される圧電セラミック粉末を得た。 Next, the powder weighed as described above is put into a pot mill containing PSZ balls, and the piezoelectric ceramic raw material powder is mixed by wet mixing by rotating the pot mill for about 90 hours using ethanol as a solvent. Obtained. The obtained piezoelectric ceramic raw material powder is dried, calcined at a temperature of 900 ° C., and then pulverized to obtain [100 {0.98 (K 0.45 N 0.53 Li 0.02 ) NbO 3 −0. 02CaZrO 3 } + 3ZrO 2 + 5MnO + 0.25Yb 2 O 3 ] was obtained.
　次に、上記のようにして得られた圧電セラミック粉末を、有機バインダ、分散剤、アセトン、可塑剤、およびＰＳＺボールとともにポットミルに投入し、ポットミルを回転させながら湿式で十分に混合し、ドクターブレード法でシート成形を行い、圧電セラミックシートを得た。 Next, the piezoelectric ceramic powder obtained as described above is put into a pot mill together with an organic binder, a dispersant, acetone, a plasticizer, and PSZ balls, and thoroughly mixed in a wet manner while rotating the pot mill. The sheet was formed by the method to obtain a piezoelectric ceramic sheet.
　また、圧電セラミック粉末のシート成形と同様に、Ｎｉ粉末と有機バインダ等をポットミルに投入して回転させながら十分に混合し、ドクターブレード法でシート成形を行い、卑金属粉末シートを作製した。 Also, similarly to the piezoelectric ceramic powder sheet molding, Ni powder and an organic binder were put in a pot mill and mixed well while rotating, and sheet molding was performed by a doctor blade method to produce a base metal powder sheet.
　次に、図１１の模式的断面図に示すように、ＰＥＴフィルム１４１上に、後に焼結金属となる卑金属粉末シート１０１ａを貼り付け、卑金属粉末シート１０１ａに、圧電セラミックシート１０２ａと、Ｎｉペーストからなる内部電極粉末１１１ａとを１層ずつ交互に積層した。ここで、卑金属粉末シート１０１ａの厚さは５μｍ、圧電セラミックシート１０２ａの厚さは５μｍ、内部電極粉末１１１ａの厚さは１μｍとした。 Next, as shown in the schematic cross-sectional view of FIG. 11, a base metal powder sheet 101a, which will later become a sintered metal, is pasted on the PET film 141, and the piezoelectric ceramic sheet 102a and Ni paste are applied to the base metal powder sheet 101a. The internal electrode powders 111a thus obtained were alternately laminated one by one. Here, the thickness of the base metal powder sheet 101a was 5 μm, the thickness of the piezoelectric ceramic sheet 102a was 5 μm, and the thickness of the internal electrode powder 111a was 1 μm.
　次に、図１１に示す積層体を静水圧加圧後、Ｎｉ－ＮｉＯ平衡酸素分圧の０．５桁還元側（Ｎｉ－ＮｉＯ平衡酸素分圧の１／３．１６の酸素分圧）になるように調整された雰囲気下で、１０００℃～１１６０℃の温度で２時間共焼結することによって、シートで焼結金属を作製した試料から、焼結金属と圧電セラミックとが一体に形成された、クラックが発生しない実施例１の圧電素子を得た。 Next, after the hydrostatic pressure was applied to the laminate shown in FIG. 11, the Ni—NiO equilibrium oxygen partial pressure was reduced to the 0.5 digit reduction side (oxygen partial pressure 1 / 3.16 of the Ni—NiO equilibrium oxygen partial pressure). The sintered metal and the piezoelectric ceramic are integrally formed from the sample in which the sintered metal is produced with the sheet by co-sintering at a temperature of 1000 ° C. to 1160 ° C. for 2 hours in an atmosphere adjusted to be In addition, the piezoelectric element of Example 1 in which no crack was generated was obtained.
　これに対して、比較のために、後に焼結金属となる卑金属粉末シート１０１ａの代わりに、Ｎｉペーストを設けた試料も作製した。Ｎｉペーストの厚みは、実施例１と同じ５μｍとした。焼結金属をペーストで作成した試料は、ペーストの塗布ムラにより焼結によるＮｉの収縮に不均一が生じ、圧電素子にクラックが発生した。  On the other hand, for comparison, a sample provided with Ni paste was also prepared instead of the base metal powder sheet 101a, which later became a sintered metal. The thickness of the Ni paste was 5 μm, the same as in Example 1. In the sample made of a sintered metal paste, nonuniform shrinkage of Ni due to sintering occurred due to uneven application of the paste, and cracks occurred in the piezoelectric element.
　したがって、圧電セラミックシートの厚みが１００μｍを下回る圧電素子の場合には、焼結金属となる部分をシート成形によって作製することで、圧電セラミックにおける微小クラックおよび剥がれの発生を特に抑制することができる。 Therefore, in the case of a piezoelectric element in which the thickness of the piezoelectric ceramic sheet is less than 100 μm, it is possible to particularly suppress the occurrence of microcracks and peeling in the piezoelectric ceramic by producing a portion that becomes a sintered metal by sheet molding.
　なお、微小クラックの発生は、圧電セラミックの表面を金属顕微鏡または電子顕微鏡で観察することにより行った。 The generation of microcracks was performed by observing the surface of the piezoelectric ceramic with a metal microscope or an electron microscope.
　次に、実施例１の圧電素子を切断し、その断面を研磨した後に、走査型電子顕微鏡にて観察を行った。その結果を図１２に示す。その画像解析を行った結果、焼結金属１０１の厚さは４．８μｍであり、圧電セラミック１０２の厚さはそれぞれ５．１μｍであり、内部電極１１１の厚さはそれぞれ１．６μｍであった。 Next, the piezoelectric element of Example 1 was cut and the cross section was polished, and then observed with a scanning electron microscope. The result is shown in FIG. As a result of the image analysis, the thickness of the sintered metal 101 was 4.8 μm, the thickness of the piezoelectric ceramic 102 was 5.1 μm, and the thickness of the internal electrode 111 was 1.6 μm. .
　また、実施例１の圧電素子の焼結金属１０１の表面について、同様に、走査型電子顕微鏡にて観察を行った。その結果を図１３に示す。図１３に示すように、実施例１の圧電素子の焼結金属１０１の表面にはＮｉ結晶粒の複数が互いに接して固着してなる構造が観察された。 Further, the surface of the sintered metal 101 of the piezoelectric element of Example 1 was similarly observed with a scanning electron microscope. The result is shown in FIG. As shown in FIG. 13, on the surface of the sintered metal 101 of the piezoelectric element of Example 1, a structure in which a plurality of Ni crystal grains were fixed in contact with each other was observed.
　比較のため、卑金属粉末シート１０１ａを塗布しなかったこと以外は実施例１と同様にして、図１４の模式的断面図に示すように、圧電セラミック粉末１０２ａと内部電極粉末１１１ａとの交互積層体（圧電セラミック粉末１０２ａ：５μｍ×３層、内部電極粉末１１１ａ：１μｍ×２層）を作製し、実施例１と同様に共焼結を行うことによって、比較例の圧電素子を作製した。 For comparison, as shown in the schematic cross-sectional view of FIG. 14, as shown in the schematic cross-sectional view of FIG. 14, except that the base metal powder sheet 101a was not applied, an alternate laminate of the piezoelectric ceramic powder 102a and the internal electrode powder 111a. (Piezoelectric ceramic powder 102a: 5 μm × 3 layers, internal electrode powder 111a: 1 μm × 2 layers) was produced, and co-sintered in the same manner as in Example 1, thereby producing a piezoelectric element of a comparative example.
　圧延加工されたＮｉ板の接着剤が塗布された表面上に、上記のようにして作製された比較例の圧電素子を設置して加圧したところ、比較例の圧電素子の圧電セラミックに微小クラックが発生して、圧電セラミックが破損した。 When the piezoelectric element of the comparative example prepared as described above was placed on the surface of the rolled Ni plate coated with the adhesive and pressed, micro cracks were formed in the piezoelectric ceramic of the comparative piezoelectric element. Occurred and the piezoelectric ceramic was damaged.
　また、比較例の圧電素子の圧延加工されたＮｉ板の表面について、同様に、走査型電子顕微鏡にて観察を行った。その結果を図１５に示す。図１５に示すように、比較例の圧電素子の圧延加工されたＮｉ板の表面には、実施例１の圧電素子の焼結金属１０１の表面のようなＮｉ結晶粒の複数が互いに接して固着してなる構造は観察されなかった。 Also, the surface of the rolled Ni plate of the piezoelectric element of the comparative example was similarly observed with a scanning electron microscope. The result is shown in FIG. As shown in FIG. 15, a plurality of Ni crystal grains such as the surface of the sintered metal 101 of the piezoelectric element of Example 1 are in contact with each other and fixed to the surface of the rolled Ni plate of the piezoelectric element of the comparative example. No structure was observed.
　［実験例２］
　実施例１と同様にして作製された圧電セラミック粉末を、溶剤およびワニスとともに混練することによってペースト状に加工した。ペースト状に加工した圧電セラミック粉末をＰＥＴフィルムの表面上に５μｍの厚さで塗布し、乾燥させた。乾燥後、内部電極粉末としてのＮｉペーストをスクリーン印刷法で１μｍの厚さで塗布し、乾燥させた。このように、圧電セラミック粉末の塗布および乾燥と、内部電極粉末の塗布および乾燥とを交互に繰り返すことによって、圧電セラミック粉末と内部電極粉末との交互積層体（圧電セラミック粉末：５μｍ×３層、内部電極粉末：１μｍ×２層）を作製し、その後、最上層の圧電セラミック粉末の表面上に実施例１と同様にして作製したＮｉシートを５μｍの厚さに塗布した後に、実施例１と同様にして、これらを静水圧加圧後に共焼結することによって、実施例２の圧電素子を作製した。実施例２の圧電素子においても、圧電セラミックの微小クラックおよび剥がれの発生は確認されなかった。 [Experiment 2]
Piezoelectric ceramic powder produced in the same manner as in Example 1 was processed into a paste by kneading together with a solvent and varnish. The paste-processed piezoelectric ceramic powder was applied on the surface of the PET film with a thickness of 5 μm and dried. After drying, Ni paste as an internal electrode powder was applied by a screen printing method to a thickness of 1 μm and dried. In this way, by alternately repeating the application and drying of the piezoelectric ceramic powder and the application and drying of the internal electrode powder, an alternate laminate of the piezoelectric ceramic powder and the internal electrode powder (piezoelectric ceramic powder: 5 μm × 3 layers, Internal electrode powder: 1 μm × 2 layers) was prepared, and then a Ni sheet prepared in the same manner as in Example 1 was applied on the surface of the uppermost piezoelectric ceramic powder to a thickness of 5 μm. Similarly, the piezoelectric element of Example 2 was produced by co-sintering these after pressing with hydrostatic pressure. Also in the piezoelectric element of Example 2, the occurrence of micro cracks and peeling of the piezoelectric ceramic was not confirmed.
　［実験例３］
　圧電セラミック粉末をドクターブレード法でシート状に加工して圧電セラミックシートを得た。また、Ｎｉ粉末からなる卑金属粉末を有機バインダ、分散剤、アセトン、可塑剤、およびＰＳＺボールとともにポットミルに投入し、ポットミルを回転させながら湿式で十分に混合し、ドクターブレード法でシート成形を行うことでシート状の卑金属シートを得た。次に、圧電セラミックシートおよび卑金属シートの厚みをそれぞれ変化させ、卑金属シート、圧電セラミックシート、および卑金属シートの順に重ね合わせた。そして、卑金属シート、圧電セラミックシート、および卑金属シートを重ね合わせたものに対して静水圧加圧をした後に共焼結を行うことによって、図１６に示す構造の実施例３の圧電素子を得た。実施例３の圧電素子の断面を鏡面研磨し、走査型電子顕微鏡（ＳＥＭ）を用いて、焼結金属と圧電セラミックとの破損状態を確認した。また、焼結金属の導通の有無を確認した。 [Experiment 3]
Piezoelectric ceramic powder was processed into a sheet by a doctor blade method to obtain a piezoelectric ceramic sheet. In addition, base metal powder made of Ni powder is put into a pot mill together with an organic binder, dispersant, acetone, plasticizer, and PSZ balls, mixed thoroughly in a wet manner while rotating the pot mill, and sheet molding is performed by the doctor blade method. A sheet-like base metal sheet was obtained. Next, the thickness of the piezoelectric ceramic sheet and the base metal sheet was changed, and the base metal sheet, the piezoelectric ceramic sheet, and the base metal sheet were superposed in this order. And the piezoelectric element of Example 3 of the structure shown in FIG. 16 was obtained by performing hydrostatic pressure pressurization with respect to what laminated | stacked the base metal sheet | seat, the piezoelectric ceramic sheet | seat, and the base metal sheet | seat. . The cross section of the piezoelectric element of Example 3 was mirror-polished, and the damaged state of the sintered metal and the piezoelectric ceramic was confirmed using a scanning electron microscope (SEM). Moreover, the presence or absence of conduction of the sintered metal was confirmed.
　具体的には、圧電セラミックシートの厚みを９０．０μｍとし、焼結金属の厚みをおのおの０．８μｍ、１．７μｍ、２．１μｍ、５．１μｍ、６．２μｍ、および１２．４μｍとして実施例３の圧電素子を作製した。そして、実施例３の各圧電素子の焼結金属の導通状態をテスターで確認した。特に良好な導通が得られた焼結金属の厚みは１．７μｍ、２．１μｍ、および５．１μｍであった。その結果を表１に示す。したがって、焼結金属の良好な導通を得る観点からは、焼結金属の厚みは１．７μｍ以上５．１μｍ以下であることが好ましい。 Specifically, the thickness of the piezoelectric ceramic sheet is 90.0 μm, and the thickness of the sintered metal is 0.8 μm, 1.7 μm, 2.1 μm, 5.1 μm, 6.2 μm, and 12.4 μm, respectively. 3 piezoelectric elements were produced. And the conduction | electrical_connection state of the sintered metal of each piezoelectric element of Example 3 was confirmed with the tester. The thicknesses of the sintered metal with which particularly good conduction was obtained were 1.7 μm, 2.1 μm, and 5.1 μm. The results are shown in Table 1. Therefore, from the viewpoint of obtaining good conduction of the sintered metal, the thickness of the sintered metal is preferably 1.7 μm or more and 5.1 μm or less.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　また、焼結金属の厚みを２．１μｍとし、圧電セラミックシートの厚みをおのおの５．０μｍ、１５．０μｍ、および２５．０μｍとしたこと以外は実施例３の圧電素子と同様にして実施例３－１の圧電素子を作製した。実施例３－１の各圧電素子の破損状態を確認した。その結果、実施例３－１の全ての圧電素子において結果が良好であった。その結果を表２に示す。 Example 3 is the same as Example 3 except that the thickness of the sintered metal is 2.1 μm and the thickness of the piezoelectric ceramic sheet is 5.0 μm, 15.0 μm, and 25.0 μm. A piezoelectric element of -1 was produced. The damaged state of each piezoelectric element in Example 3-1 was confirmed. As a result, all the piezoelectric elements of Example 3-1 showed good results. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　また、焼結金属の厚みを２．１μｍとし、圧電セラミックシートの厚みを１５．０μｍとしたこと以外は実施例３の圧電素子と同様にして実施例３－２の圧電素子を作製した。実施例３－２の圧電素子に５ｋＶ/ｍｍの電圧を印加して分極処理を行った。その後、ＳＨＩＭＡＺＵ製マイクロオートグラフＭＳＴ－Ｉを用いて支点間距離を４ｍｍとし、０．１Ｎ以上の３点曲げ力を繰り返し加えた。それによる発生電荷をＫＥＩＴＨＬＥＹ製エレクトロメータ６５１４で計測した。その結果を図１７に示す。図１７に示すように、実施例３－２の圧電素子には、圧電歪による発生電荷が生じていることが確認された。 Further, a piezoelectric element of Example 3-2 was manufactured in the same manner as the piezoelectric element of Example 3 except that the thickness of the sintered metal was 2.1 μm and the thickness of the piezoelectric ceramic sheet was 15.0 μm. Polarization treatment was performed by applying a voltage of 5 kV / mm to the piezoelectric element of Example 3-2. Thereafter, using a SHIMAZU micro-autograph MST-I, the distance between the fulcrums was set to 4 mm, and a three-point bending force of 0.1 N or more was repeatedly applied. The charge generated thereby was measured with an electrometer 6514 manufactured by KEITHLEY. The result is shown in FIG. As shown in FIG. 17, it was confirmed that charges generated by piezoelectric strain were generated in the piezoelectric element of Example 3-2.
　なお、表１および表２の評価の欄における「Ａ」の表記は評価が良好であることを示しており、「Ｂ」の表記は評価が良好ではないことを示している。 In addition, the notation “A” in the evaluation column of Tables 1 and 2 indicates that the evaluation is good, and the notation “B” indicates that the evaluation is not good.
　以上のように本発明の実施の形態および実施例について説明を行なったが、上述の各実施の形態および各実施例の構成を適宜組み合わせることも当初から予定している。 Although the embodiments and examples of the present invention have been described as described above, it is also planned from the beginning to appropriately combine the configurations of the above-described embodiments and examples.
　今回開示された実施の形態および実施例はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて請求の範囲によって示され、請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。 It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
　実施態様の圧電素子は、たとえば、スキャナ、カメラモジュールまたはウエアラブル装置等に用いられる小型低背の圧電アクチュエータ、または様々な圧電センサーに利用できる可能性がある。 There is a possibility that the piezoelectric element of the embodiment can be used for, for example, a small and low-profile piezoelectric actuator used in a scanner, a camera module, a wearable device, or the like, or various piezoelectric sensors.
　１　焼結金属、１ａ　卑金属粉末、２　圧電セラミック、２ａ　圧電セラミック粉末、３　外部電極、３ａ　外部電極粉末、１１　第１の内部電極、１１ａ　第１の内部電極粉末、１２　第２の内部電極、１２ａ　第２の内部電極粉末、２１　第１の側面、２２　第２の側面、３１　第１の接続電極、３２　第２の接続電極、４１　基材、１０１　焼結金属、１０１ａ　卑金属粉末シート、１０２　圧電セラミック、１０２ａ　圧電セラミック粉末、１０３　外部電極、１１１　内部電極、１１１ａ　内部電極粉末。 1 sintered metal, 1a base metal powder, 2 piezoelectric ceramic, 2a piezoelectric ceramic powder, 3 external electrode, 3a external electrode powder, 11 first internal electrode, 11a first internal electrode powder, 12 second internal electrode, 12a 2nd internal electrode powder, 21 1st side surface, 22 2nd side surface, 31 1st connection electrode, 32 2nd connection electrode, 41 base material, 101 sintered metal, 101a base metal powder sheet, 102 piezoelectric ceramic , 102a piezoelectric ceramic powder, 103 external electrode, 111 internal electrode, 111a internal electrode powder.

Claims (14)

  1. 　卑金属を含む焼結金属と、
    　前記焼結金属と一体に設けられた圧電セラミックと、を備え、
    　前記圧電セラミックは、ペロブスカイト型化合物を主要物質として含み、
    　前記主要物質は、ニオブと、アルカリ金属と、酸素とを含み、
    　前記圧電セラミックに含まれる全物質の総モル量に対する前記主要物質の含有量が９０％モル以上である、圧電素子。     Sintered metals including base metals,
    A piezoelectric ceramic provided integrally with the sintered metal,
    The piezoelectric ceramic contains a perovskite compound as a main substance,
    The main substance includes niobium, an alkali metal, and oxygen,
    The piezoelectric element, wherein a content of the main substance is 90% mol or more with respect to a total molar amount of all substances contained in the piezoelectric ceramic.
  2. 　前記焼結金属と対向して前記圧電セラミックに設けられた外部電極をさらに備え、
    　前記外部電極は、前記圧電セラミックと一体に設けられている、請求項１に記載の圧電素子。     Further comprising an external electrode provided on the piezoelectric ceramic facing the sintered metal,
    The piezoelectric element according to claim 1, wherein the external electrode is provided integrally with the piezoelectric ceramic.
  3. 　前記圧電セラミックは、一方主面と、他方主面とを有し、
    　前記焼結金属は、前記圧電セラミックを挟み込むように前記圧電セラミックの前記一方主面及び前記他方主面に設けられている、請求項１に記載の圧電素子。     The piezoelectric ceramic has one main surface and the other main surface,
    The piezoelectric element according to claim 1, wherein the sintered metal is provided on the one main surface and the other main surface of the piezoelectric ceramic so as to sandwich the piezoelectric ceramic.
  4. 　前記圧電セラミックの厚みが１００μｍ以下である、請求項１から３のいずれか１項に記載の圧電素子。 The piezoelectric element according to any one of claims 1 to 3, wherein the thickness of the piezoelectric ceramic is 100 µm or less.
  5. 　前記焼結金属の厚みが１．７μｍ以上５．１μｍ以下である、請求項１から４のいずれか１項に記載の圧電素子。 The piezoelectric element according to any one of claims 1 to 4, wherein the sintered metal has a thickness of 1.7 µm or more and 5.1 µm or less.
  6. 　前記圧電セラミックの内部に設けられた内部電極をさらに備え、
    　前記内部電極は、前記圧電セラミックと一体に設けられている、請求項１から５のいずれか１項に記載の圧電素子。     Further comprising an internal electrode provided inside the piezoelectric ceramic,
    The piezoelectric element according to claim 1, wherein the internal electrode is provided integrally with the piezoelectric ceramic.
  7. 　前記内部電極は、第１の内部電極と、第２の内部電極とを含み、
    　前記第１の内部電極は、前記圧電セラミックの第１の側面から前記焼結金属と向かい合うようにして延在し、前記圧電セラミックの第２の側面まで達しないように設けられており、
    　前記第２の内部電極は、前記圧電セラミックの前記第２の側面から前記焼結金属と向かい合うようにして延在し、前記圧電セラミックの前記第１の側面まで達しないように設けられており、
    　前記第１の内部電極と前記第２の内部電極とは間隔を空けて向かい合うようにして設けられている、請求項６に記載の圧電素子。     The internal electrode includes a first internal electrode and a second internal electrode,
    The first internal electrode extends from the first side surface of the piezoelectric ceramic so as to face the sintered metal, and is provided so as not to reach the second side surface of the piezoelectric ceramic.
    The second internal electrode extends from the second side surface of the piezoelectric ceramic so as to face the sintered metal, and is provided so as not to reach the first side surface of the piezoelectric ceramic,
    The piezoelectric element according to claim 6, wherein the first internal electrode and the second internal electrode are provided to face each other with a space therebetween.
  8. 　前記圧電セラミックの前記第１の側面に設けられた第１の接続電極と、
    　前記圧電セラミックの前記第２の側面に設けられた第２の接続電極と、を備え、
    　前記第１の接続電極は、前記第１の内部電極と前記焼結金属とを電気的に接続しており、
    　前記第２の接続電極は、前記第２の内部電極と前記外部電極とを電気的に接続してなる、請求項７に記載の圧電素子。     A first connection electrode provided on the first side surface of the piezoelectric ceramic;
    A second connection electrode provided on the second side surface of the piezoelectric ceramic,
    The first connection electrode electrically connects the first internal electrode and the sintered metal,
    The piezoelectric element according to claim 7, wherein the second connection electrode is formed by electrically connecting the second internal electrode and the external electrode.
  9. 　前記卑金属は、ニッケル、銅、およびアルミニウムからなる群から選択された少なくとも１種を含む、請求項１～８のいずれか１項に記載の圧電素子。 The piezoelectric element according to any one of claims 1 to 8, wherein the base metal includes at least one selected from the group consisting of nickel, copper, and aluminum.
  10. 　卑金属を含む焼結金属と、前記焼結金属と一体に設けられた圧電セラミックとを備え、前記圧電セラミックは、ペロブスカイト型化合物を主要物質として含み、前記主要物質は、ニオブと、アルカリ金属と、酸素とを含み、前記圧電セラミックに含まれる全物質の総モル量に対する前記主要物質の含有量が９０モル％以上である圧電素子の製造方法であって、
    　圧電セラミック粉末と卑金属粉末とを重ね合わせる第１の工程と、
    　重ね合わされた前記圧電セラミック粉末と前記卑金属粉末とを共焼結する第２の工程と、を含む、圧電素子の製造方法。     A sintered metal including a base metal and a piezoelectric ceramic provided integrally with the sintered metal, the piezoelectric ceramic including a perovskite-type compound as a main material, the main material being niobium, an alkali metal, A method for producing a piezoelectric element, comprising oxygen, wherein the content of the main substance is 90 mol% or more with respect to the total molar quantity of all substances contained in the piezoelectric ceramic,
    A first step of superimposing piezoelectric ceramic powder and base metal powder;
    And a second step of co-sintering the piezoelectric ceramic powder and the base metal powder that are superposed on each other.
  11. 　前記第１の工程は、複数の前記圧電セラミック粉末の間に内部電極粉末を重ね合わせる工程をさらに含み、
    　前記第２の工程において、重ね合わされた前記圧電セラミック粉末と前記卑金属粉末と前記内部電極粉末とを共焼結する、請求項１０に記載の圧電素子の製造方法。     The first step further includes a step of superposing an internal electrode powder between the plurality of piezoelectric ceramic powders,
    The method for manufacturing a piezoelectric element according to claim 10, wherein in the second step, the piezoelectric ceramic powder, the base metal powder, and the internal electrode powder that are superimposed are co-sintered.
  12. 　前記第２の工程は、重ね合わされた前記圧電セラミック粉末と前記卑金属粉末とをＺｒＯ2、Ａｌ2Ｏ3およびＳｉＯ2からなる群から選択された少なくとも１つ以上含む物質を主要物質とするセラミックで挟み、共焼結する、請求項１０または１１に記載の圧電素子の製造方法。 The second step is a ceramic mainly composed of a material containing at least one or more selected from the group consisting of ZrO 2 , Al 2 O 3 and SiO 2 with the piezoelectric ceramic powder and the base metal powder superimposed. The method for manufacturing a piezoelectric element according to claim 10 or 11, wherein the piezoelectric element is sandwiched and co-sintered.
  13. 　前記第２の工程は、前記卑金属と前記卑金属の酸化物とが平衡となる酸素分圧の１０００倍以下の酸素分圧の雰囲気下で行われる、請求項１０から１２のいずれか１項に記載の圧電素子の製造方法。 13. The method according to claim 10, wherein the second step is performed in an atmosphere having an oxygen partial pressure equal to or lower than 1000 times an oxygen partial pressure at which the base metal and the base metal oxide are in equilibrium. Manufacturing method of the piezoelectric element.
  14. 　請求項１から９のいずれか１項に記載の圧電素子を備える、圧電振動子。 A piezoelectric vibrator comprising the piezoelectric element according to any one of claims 1 to 9.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11380837B2 (en) 2015-10-27 2022-07-05 Murata Manufacturing Co., Ltd. Piezoelectric device and method for manufacturing piezoelectric device
US11508901B2 (en) 2017-11-09 2022-11-22 Murata Manufacturing Co., Ltd. Piezoelectric component, sensor, and actuator

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006100807A1 (en) * 2005-03-24 2006-09-28 Murata Manufacturing Co., Ltd Piezoelectric element and process for producing piezoelectric element
JP2008207999A (en) * 2007-02-27 2008-09-11 Konica Minolta Holdings Inc Method for manufacturing piezoelectric ceramic composition
JP2009256182A (en) * 2008-03-21 2009-11-05 Ngk Insulators Ltd Piezoelectric/electrostrictive ceramic composition manufacturing method
JP2013219250A (en) * 2012-04-10 2013-10-24 Murata Mfg Co Ltd Piezoelectric ceramic electronic part, and manufacturing method thereof

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012132660A1 (en) * 2011-03-28 2012-10-04 日本碍子株式会社 Piezoelectric device and production method for green compact being molded body of piezoelectric device prior to sintering
JP2014143220A (en) * 2011-03-28 2014-08-07 Ngk Insulators Ltd Ceramic device and piezoelectric device
JP5827866B2 (en) * 2011-10-20 2015-12-02 日本碍子株式会社 Film-type piezoelectric / electrostrictive element and manufacturing method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006100807A1 (en) * 2005-03-24 2006-09-28 Murata Manufacturing Co., Ltd Piezoelectric element and process for producing piezoelectric element
JP2008207999A (en) * 2007-02-27 2008-09-11 Konica Minolta Holdings Inc Method for manufacturing piezoelectric ceramic composition
JP2009256182A (en) * 2008-03-21 2009-11-05 Ngk Insulators Ltd Piezoelectric/electrostrictive ceramic composition manufacturing method
JP2013219250A (en) * 2012-04-10 2013-10-24 Murata Mfg Co Ltd Piezoelectric ceramic electronic part, and manufacturing method thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11380837B2 (en) 2015-10-27 2022-07-05 Murata Manufacturing Co., Ltd. Piezoelectric device and method for manufacturing piezoelectric device
US11508901B2 (en) 2017-11-09 2022-11-22 Murata Manufacturing Co., Ltd. Piezoelectric component, sensor, and actuator
DE112018003429B4 (en) 2017-11-09 2023-01-12 Murata Manufacturing Co., Ltd. Piezoelectric component, sensor and actuator

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