WO2015163685A1 - Lead-free piezoelectric material for vehicle knock sensor, method for manufacturing same, and vehicle knock sensor comprising same - Google Patents

Lead-free piezoelectric material for vehicle knock sensor, method for manufacturing same, and vehicle knock sensor comprising same Download PDF

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WO2015163685A1
WO2015163685A1 PCT/KR2015/004011 KR2015004011W WO2015163685A1 WO 2015163685 A1 WO2015163685 A1 WO 2015163685A1 KR 2015004011 W KR2015004011 W KR 2015004011W WO 2015163685 A1 WO2015163685 A1 WO 2015163685A1
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piezoelectric
powder
cuo
piezoelectric material
mixture
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남산
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고려대학교 산학협력단
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • 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
    • 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

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  • the present invention relates to a non-connected piezoelectric material for a vehicle knocking sensor, a method of manufacturing the same, and a vehicle knocking sensor including the same, and more particularly, to a non-linked piezoelectric material which does not include lead (Pb) and converts mechanical energy and electrical energy.
  • the present invention relates to a method of manufacturing the non-connected piezoelectric body and a vehicle knocking sensor.
  • Piezoelectric materials are widely used as materials for ultrasonic vibrators, electromechanical transducers, and actuator components used in a wide range of fields such as ultrasonic devices, imaging devices, audio devices, communication devices, and sensors.
  • PZT Pb (Zr, Ti) O 3
  • lead (Pb) is a highly toxic material, and volatilized during the sintering process, causing serious environmental pollution. Therefore, research and development on non-connected piezoelectric elements to replace PZT is being actively conducted.
  • the non-piezoelectric material has excellent characteristics that can be applied as a vibration sensor for a vehicle knocking sensor. Therefore, if only a suitable composition for a non-piezoelectric material is developed, it may be possible to substitute PZT. In addition, through the development of the composition of the non-piezoelectric material, not only vibration sensors such as automobile knocking sensors, but also piezoelectric acoustic components and actuators can be sufficiently utilized.
  • BaTiO 3 , (Bi 1/2 Na 1/2 ) TiO 3 and Alkali-Niobate-based ceramics are materials that form a non-connected piezoelectric material.
  • the alkali-based ceramics have excellent piezoelectric properties and have a high phase transition temperature (T c ) of 400 ° C. or higher.
  • NKN NbO 3
  • KN KNbO 3
  • KN KN ceramics
  • NKN-LNTS has been researched as a non-linked piezoelectric material that can replace PZT.
  • NKN ceramics are sintered due to volatilization of sodium (Na) at high temperatures of 1,000 ° C or higher. This volatilization of sodium makes it difficult to fully sinter NKN ceramics and lowers the insulation resistance of the ceramic itself. The decrease in the insulation resistance may affect the polarization process of the piezoelectric ceramics, which may lead to deterioration of the piezoelectric properties.
  • the NKN ceramics are sintered at low temperature to suppress volatilization of sodium and at the same time, research for improvement of piezoelectric properties is needed.
  • KN piezoelectric material has a higher phase transition temperature (T c ) than conventional non-lead piezoelectric materials, and thus, many studies have been conducted since it has been recognized as a possibility as a non-connected piezoelectric material that can replace PZT.
  • T c phase transition temperature
  • the present invention has been made in view of such a problem, and an object of the present invention is to provide a non-connected piezoelectric material for an automobile knock sensor having improved piezoelectric properties.
  • Another object of the present invention is to provide a method for producing a non-connected piezoelectric material for an automotive knock sensor having excellent piezoelectric properties which can be produced at a reduced sintering temperature through a relatively simple manufacturing process.
  • the non-connected piezoelectric material for a vehicle knocking sensor (Na 1-x K x ) NbO 3 ; And z mol% of additive CuO, and is formed at a sintering temperature of 940 to 980 ° C.
  • (Na 2 CO 3 or K 2 CO 3 ) and Nb 2 O 5 are mixed as raw materials to form a first mixture, and the first mixture is formed using a first milling process and a second drying process using the first mixture.
  • the first powder was calcined to form (Na 1-x K x ) NbO 3 powder, where x is 0.5 or 1, and z mol% of additives to the (Na 1-x K x ) NbO 3 powder CuO, where 0.5 ⁇ z ⁇ 2.0, is added to form a second mixture.
  • a second powder is formed through the second milling process and the second drying process using the second mixture, and the second powder is sintered at a temperature of 940 to 980 ° C to form a sintered body.
  • the first milling process may be put in a nylon jar (nylon jar) with anhydrous alcoholic solvent can be crushed for 2 to 24 hours using a zirconia ball.
  • the second milling process may be put into a nylon jar (nylon jar) with anhydrous alcoholic solvent and pulverized for 48 to 72 hours using a zirconia ball.
  • the process of sintering the second powder to form a sintered body may be performed for 2 to 20 hours.
  • the non-connected piezoelectric piezoelectric sensor for automobile knocking sensor and the manufacturing method thereof according to the embodiments of the present invention described above CuO is added and lead (Pb) is not added, thereby preventing environmental problems. Furthermore, the non-connected piezoelectric body can be manufactured through a relatively simple process. In particular, as the low-temperature sintering process is possible at a temperature lower than 1,000 ° C., volatilization of Na 2 O and K 2 O is suppressed, thereby making a non-connected piezoelectric body having a uniform composition. Furthermore, the non-connected piezoelectric element to which CuO is added can implement excellent piezoelectric and dielectric properties.
  • the non-connected piezoelectric body according to the embodiments of the present invention described above has a relatively high piezoelectric voltage constant (g 33 ) value, quality coefficient (Q m ) value, and high phase transition temperature to be suitable for various vibration sensors including a knocking sensor for a vehicle.
  • (T c ) value it can be used for non-connected piezoelectric sensor.
  • FIG. 1 is a flowchart illustrating a method of manufacturing a non-connected piezoelectric material for a vehicle knocking sensor according to embodiments of the present invention.
  • FIG. 2 is a graph showing changes in relative density, dielectric properties, and piezoelectric properties of CuO-added NKN piezoelectric bodies with sintering temperature.
  • FIG. 4 is a graph showing changes in relative density, dielectric properties, and piezoelectric properties of a KN piezoelectric body added with CuO sintered at 960 ° C. for 2.0 hours.
  • Example 5 is a sensor sensitivity characteristics of a knocking sensor manufactured using an NKN piezoelectric material (Example 1) added with CuO sintered at 960 ° C. for 2.0 hours and a vehicle knocking sensor using PZT (existing commercially available, comparative example). This is a graph.
  • Non-connected piezoelectric for automotive knock sensor according to an embodiment of the present invention (Na 1-x K x ) NbO 3 ; And z mol% of additive CuO, and is formed at a sintering temperature of 940 to 980 ° C.
  • first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.
  • the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.
  • Non-connected piezoelectric for automotive knocking sensor includes (Na 1-x K x ) NbO 3 and z mol% of additive CuO.
  • x is 0.5 or 1 and has a range of 0.5 ⁇ z ⁇ 2.0. That is, when x is 0.5, the non-connected piezoelectric material includes (Na 0.5 K 0.5 ) NbO 3, and thus, corresponds to the NKN-based piezoelectric material.
  • x is 1, KNbO 3 is included, so the non-connected piezoelectric material includes (N 0.5 K 0.5 ) NbO 3 . do.
  • the additive includes CuO.
  • the additive reacts with (Na 1-x K x ) NbO 3 to form an intermediate in the sintering process of manufacturing the non-connected piezoelectric body, and the intermediate has a relatively low melting point, thereby liquid phase sintering at a reduced sintering temperature. Allow this to proceed. That is, the sintering process may be performed at a sintering temperature of 940 to 980 ° C. Thus, as the sintering process proceeds at the reduced sintering temperature, volatilization of Na 2 O and K 2 O is suppressed, thereby making a non-connected piezoelectric body having a uniform composition.
  • the non-connected piezoelectric element to which CuO is added may implement excellent piezoelectric and dielectric properties.
  • FIG. 1 is a flowchart illustrating a method of manufacturing a non-connected piezoelectric material for a vehicle knocking sensor according to embodiments of the present invention.
  • the composition of the first mixture of purity of 99% or more (Na 2 CO 3 K 2 CO 3 ) and Nb 2 O 5 are subjected to a batch process for calculating the mass ratio, and then a basis weight process for weighing each weight according to the batch results is performed. Then, according to the batch process and basis weight process according to the amount (Na 2 CO 3 or K 2 CO 3 ) and Nb 2 O 5 are mixed to form a first mixture. That is, when Na 2 CO 3, K 2 CO 3 and Nb 2 O 5 are mixed to form a first mixture, an NKN series piezoelectric body is formed, while K 2 CO 3 and Nb 2 O 5 are mixed to form a first mixture. When forming a mixture, a KN series piezoelectric body may be formed.
  • the first mixture is used to form a first powder through a first milling process and a second drying process (S120).
  • a first ball-milling process of wet mixing using anhydrous alcohol solvent for 2 to 24 hours with a zirconia ball in a nylon jar and grinding it into powder This can be done.
  • a drying process of removing the mixed anhydrous alcohol in the first ball-milling process is performed to form a first powder in powder form.
  • the non-connected piezoelectric material includes (Na 0.5 K 0.5 ) NbO 3, and thus, corresponds to the NKN-based piezoelectric material, and when x is 1, KNbO 3 is included and thus corresponds to the KN-based piezoelectric material. do.
  • the calcination process may be performed at 800 to 1000 ° C. for 2 to 10 hours.
  • the additive reacts with (Na 1-x K x ) NbO 3 to form an intermediate during the subsequent sintering process and allows the liquid phase sintering process to proceed at a reduced sintering temperature as the intermediate has a relatively low melting point. . That is, the sintering process may be performed at a sintering temperature of 940 to 980 ° C.
  • the sintering process proceeds at the reduced sintering temperature, volatilization of Na 2 O and K 2 O is suppressed, thereby making a non-connected piezoelectric body having a uniform composition.
  • the non-connected piezoelectric element to which CuO is added may implement excellent piezoelectric and dielectric properties.
  • a second powder is formed through the second milling process and the second drying process using the second mixture.
  • the second powder is wet-mixed for 48 to 72 hours with anhydrous alcohol solvent to the second powder consisting of (Na 1-x K x ) NbO 3 and CuO, and crushed using a zirconia ball -Second ball-milling process can be performed.
  • a drying process may be performed to remove the anhydrous alcoholic solvent used in the second ball-milling process.
  • NKN and KN-based second powder to which CuO was added as an additive is formed.
  • the sintered body may be a piezoelectric material used in a sound wave device, an imaging device, an audio device, a communication device, a sensor, an ultrasonic vibrator, an electromechanical transducer, or an actuator, and may have various shapes and sizes.
  • a sieving process for filtering the second powder into a homogeneous size and a pressing process for performing the filtered powder to have a specific shape are performed in advance.
  • the sintered body may be press-molded to have a cylinder shape or a ring shape.
  • a post-treatment process may be additionally performed on the sintered body.
  • an electrode material is applied to the surface of the sintered body and immersed in silicon oil, and a 3 to 5 kV / mm DC bias may be applied for 1 hour at a temperature of 120 to 150 ° C.
  • the first mixture by mixing Na 2 CO 3 , K 2 CO 3 and Nb 2 O 5 , which is an initial raw material with a purity of 99.9%, and wet mixing with zirconia balls in a nylon jar using anhydrous alcoholic solvent for 24 hours. Formed.
  • the first mixture was dried and then calcined at 950 ° C. for 3 hours to synthesize (Na 0.5 K 0.5 ) NbO 3 (Example 1) and KNbO 3 (Example 2) powders to prepare a first powder.
  • 0.5-5.0 mol% of CuO was added to the first powder, wet mixed and pulverized with anhydrous alcoholic solvent for 72 hours, and then dried to form a second mixture.
  • the dried powder was sintered at 960 ° C. for 2 hours after pressure molding into a cylindrical shaped body having a diameter of 18 mm and a height of about 1.3 to 1.5 mm to form a sintered body.
  • the characteristics were measured after 24 hours after applying a 3-5 kV / mm DC bias for 1 hour at 120-150 ° C. in a silicone oil.
  • FIG. 2 is a graph showing changes in relative density, dielectric properties, and piezoelectric properties of NKN piezoelectric material (Example 1) to which CuO is added according to a change in sintering temperature.
  • Example 3 are electron scanning micrographs showing the microstructure of the KN piezoelectric body (Example 2) added with CuO sintered at 960 ° C. for 2.0 hours according to the change of CuO addition amount.
  • Example 4 is a graph showing changes in relative density, dielectric properties, and piezoelectric properties of a KN piezoelectric body (Example 2) added with CuO sintered at 960 ° C. for 2.0 hours.
  • the sample without CuO at 960 ° C. is not sintered so that the relative density is very low.
  • the liquid phase sintering of the KN piezoelectric body generates a relative density of theoretical density. 95.5%.
  • the piezoelectric strain constant (d 33 ), piezoelectric voltage constant (g 33 ), and dielectric constant and electromechanical coupling constant (K p ) of the KN piezoelectric tend to decrease gradually with the addition amount of CuO.
  • the mechanical quality factor (Q m ) increases rapidly with the addition of CuO. This can be explained by the hardening effect caused by the solid solution of Cu as KN. Particularly, the specimen with 1.5 mol% CuO showed high Q m of 2,300.
  • the piezoelectric voltage constant g 33 has a high value of 44 Vm / N.
  • the piezoelectric voltage constant is the highest value of the non-lead ceramic piezoelectric material known so far, and it can be understood that the piezoelectric voltage constant can be sufficiently applied to a knocking sensor for a vehicle, which is a type of vibration sensor.
  • Example 5 is a sensor sensitivity characteristics of a knocking sensor using a vehicle knocking sensor prepared using NKN piezoelectric material (Example 1) added CuO sintered at 960 ° C. for 2.0 hours and PZT (existing commercially available, comparative example). This is a graph.
  • Example 1 (Na 0.5 K 0.5 ) NbO 3 [NKN] + 1.5 mol% CuO), Example 2 (KNbO 3 [KN] + 1.0 mol% CuO) and Comparative Example (P-6C TM , Murata Co., Ltd.) Dielectric properties and piezoelectric properties for) are summarized in the table below.
  • Example 1 and Example 2 it can be seen that it has superior piezoelectric properties suitable for the vibration sensor than the comparative example. In particular, it can be seen that the piezoelectric voltage constant which directly affects the sensitivity of the vibration sensor is high.
  • the non-connected piezoelectric body according to the embodiments of the present invention can be directly applied to the production of vibration sensors, particularly knocking sensors for automobiles by adjusting the amount of additive (CuO).

Abstract

A lead-free piezoelectric material for a vehicle knock sensor is formed at a sintering temperature of from 940 to 980℃, and comprises: (Na1-xKx)NbO3; and an additive CuO of z mol%, wherein x is 0.5 or 1, and 0.5≤z≤2.0.

Description

자동차 노킹 센서용 비연계 압전체, 이의 제조 방법 및 이를 포함하는 자동차 노킹 센서Non-connected piezoelectric for automotive knock sensor, manufacturing method thereof and automobile knock sensor including the same
본 발명은 자동차 노킹 센서용 비연계 압전체, 이의 제조 방법 및 이를 포함하는 자동차 노킹 센서에 관한 것으로, 보다 상세하게는 납(Pb)을 포함하지 않고 기계적 에너지 및 전기적 에너지를 상호 변환시키는 비연계 압전체 및 상기 비연계 압전체의 제조 방법 및 자동차 노킹 센서에 관한 것이다.The present invention relates to a non-connected piezoelectric material for a vehicle knocking sensor, a method of manufacturing the same, and a vehicle knocking sensor including the same, and more particularly, to a non-linked piezoelectric material which does not include lead (Pb) and converts mechanical energy and electrical energy. The present invention relates to a method of manufacturing the non-connected piezoelectric body and a vehicle knocking sensor.
압전체는 초음파 기기, 영상기기, 음향기기, 통신기기, 센서 등의 광범위한 분야에 이용되는 초음파 진동자, 전기기계 트랜스듀서(transducer), 액추에이터(actuator) 부품들의 재료로 널리 사용되고 있다.Piezoelectric materials are widely used as materials for ultrasonic vibrators, electromechanical transducers, and actuator components used in a wide range of fields such as ultrasonic devices, imaging devices, audio devices, communication devices, and sensors.
지금까지는 Pb(Zr,Ti)O3(이하; PZT) 계열의 압전 재료가 높은 특성을 가져 대부분의 압전 부품 재료로 활용되고 있다. 하지만 납(Pb)은 독성이 강한 물질이고, 소결 공정 중 휘발이 되어 심각한 환경오염을 일으키고 있다. 따라서 PZT를 대체하기 위한 비연계 압전체에 대한 연구 개발이 활발히 진행되고 있다. Until now, Pb (Zr, Ti) O 3 (hereinafter referred to as PZT) series piezoelectric materials have high properties and are used as most piezoelectric component materials. However, lead (Pb) is a highly toxic material, and volatilized during the sintering process, causing serious environmental pollution. Therefore, research and development on non-connected piezoelectric elements to replace PZT is being actively conducted.
한편, 비연 압전체의 경우 자동차 노킹 센서용 진동 센서로 응용될 수 있는 우수한 특성을 지니고 있다. 따라서, 비연 압전체에 대한 적합한 조성만 개발이 된다면 PZT를 대체할 수 있을 것으로 판단된다. 뿐만 아니라, 상기 비연 압전체의 조성의 개발을 통해 자동차 노킹 센서와 같은 진동 센서뿐 아니라, 압전 음향 부품 및 액추에이터 등에도 충분히 활용이 가능하다.On the other hand, the non-piezoelectric material has excellent characteristics that can be applied as a vibration sensor for a vehicle knocking sensor. Therefore, if only a suitable composition for a non-piezoelectric material is developed, it may be possible to substitute PZT. In addition, through the development of the composition of the non-piezoelectric material, not only vibration sensors such as automobile knocking sensors, but also piezoelectric acoustic components and actuators can be sufficiently utilized.
비연계 압전체를 이루는 물질로서 BaTiO3,(Bi1/2Na1/2)TiO3 및 Alkali-Niobate 계열 세라믹스가 있다. 상기 알칼리 계열 세라믹스는 압전 특성이 우수하고 400℃ 이상의 높은 상전이 온도(Tc)를 가지고 있다.BaTiO 3 , (Bi 1/2 Na 1/2 ) TiO 3 and Alkali-Niobate-based ceramics are materials that form a non-connected piezoelectric material. The alkali-based ceramics have excellent piezoelectric properties and have a high phase transition temperature (T c ) of 400 ° C. or higher.
최근에는 알칼리 계열 세라믹스의 일종인 (Na,K)NbO3 (이하, NKN 이라 함) 및 KNbO3 (이하, KN 이라 함) 세라믹에 관한 많은 연구가 진행되어 왔다. 특히, NKN-LNTS는 PZT와 유사한 압전 특성을 보인다는 내용이 Nature에 발표되는 등 현재 PZT를 대체할 수 있는 비연계 압전체로 많은 연구가 진행되어 왔다. 하지만 NKN 세라믹스는 1,000℃ 이상의 높은 온도에서 나트륨(Na)의 휘발로 인한 소결이 이루어진다. 이러한 나트륨 휘발로 인해 NKN세라믹스의 완벽한 소결이 어렵고 세라믹 자체의 절연 저항이 떨어지게 된다. 절연 저항의 감소는 압전 세라믹의 분극 공정에 영향을 미쳐 압전 특성의 악화를 초래할 수 있다.Recently, many studies have been conducted on (Na, K) NbO 3 (hereinafter referred to as NKN) and KNbO 3 (hereinafter referred to as KN) ceramics, which are a type of alkali-based ceramics. In particular, NKN-LNTS has been researched as a non-linked piezoelectric material that can replace PZT. However, NKN ceramics are sintered due to volatilization of sodium (Na) at high temperatures of 1,000 ° C or higher. This volatilization of sodium makes it difficult to fully sinter NKN ceramics and lowers the insulation resistance of the ceramic itself. The decrease in the insulation resistance may affect the polarization process of the piezoelectric ceramics, which may lead to deterioration of the piezoelectric properties.
따라서 이러한 NKN 세라믹스를 저온에서 소결하여 나트륨의 휘발을 억제하는 동시에 압전 특성의 향상을 위한 연구가 필요하며, 상기 문제를 해결할 경우 다양한 분야에서 PZT를 대체할 비연압전 조성을 확보할 수 있을 것으로 판단된다.Therefore, the NKN ceramics are sintered at low temperature to suppress volatilization of sodium and at the same time, research for improvement of piezoelectric properties is needed.
한편, KN 비연계 압전체의 경우 2001년에 S. Wada 등이 KN 단결정이 우수한 압전 특성과 상대적으로 430℃의 높은 상전이 온도를 가지고 있다고 보고하였다. 하지만 KN제조에 있어 K2O가 1,000℃이상의 높은 소결 온도에서 휘발되어 2차상이 형성되므로 압전 특성이 저하 되는 심각한 문제가 되어 왔다. On the other hand, in the case of the KN non-connected piezoelectric material, in 2001, S. Wada reported that the KN single crystal had excellent piezoelectric properties and relatively high phase transition temperature of 430 ° C. However, K 2 O in the manufacture KN is volatilized at least 1,000 ℃ high sintering temperature, the secondary phase is formed has been a serious problem that the piezoelectric property degraded.
이와 같이 KN 압전체는 기존 비연 압전 재료에 비해 높은 상전이 온도(Tc)를 가져, PZT를 대체 할 수 있는 비연계 압전체로 가능성을 인정받아서 많은 연구가 진행되어 왔다. 하지만 제조 공정이 복잡하고, 압전 특성이 낮으며, 소결 온도가 KN 세라믹의 융점과 비슷한 단점이 있다.As described above, KN piezoelectric material has a higher phase transition temperature (T c ) than conventional non-lead piezoelectric materials, and thus, many studies have been conducted since it has been recognized as a possibility as a non-connected piezoelectric material that can replace PZT. However, there are disadvantages in that the manufacturing process is complicated, the piezoelectric properties are low, and the sintering temperature is similar to that of the KN ceramic.
본 발명은 이와 같은 문제점을 감안한 것으로써, 본 발명의 일 목적은 개선된 압전 특성을 갖는 자동차 노킹 센서용 비연계 압전체를 제공하는 것이다.SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object of the present invention is to provide a non-connected piezoelectric material for an automobile knock sensor having improved piezoelectric properties.
본 발명의 다른 목적은 상대적으로 간단한 제조 공정을 통하여 감소된 소결 온도에서 제조될 수 있는 우수한 압전 특성을 갖는 자동차 노킹 센서용 비연계 압전체의 제조 방법을 제공하는 것이다.Another object of the present invention is to provide a method for producing a non-connected piezoelectric material for an automotive knock sensor having excellent piezoelectric properties which can be produced at a reduced sintering temperature through a relatively simple manufacturing process.
본 발명의 일 목적을 달성하기 위하여, 본 발명의 실시예에 따른 자동차 노킹 센서용 비연계 압전체는 (Na1-xKx)NbO3; 및 z mol%의 첨가제 CuO를 포함하고, 940 내지 980℃의 소결 온도에서 형성된다. 여기서, x는 0.5 또는 1이며, 0.5≤z≤2.0 이다.In order to achieve the object of the present invention, the non-connected piezoelectric material for a vehicle knocking sensor according to an embodiment of the present invention (Na 1-x K x ) NbO 3 ; And z mol% of additive CuO, and is formed at a sintering temperature of 940 to 980 ° C. Here, x is 0.5 or 1 and 0.5 <= z <= 2.0.
본 발명의 다른 목적을 달성하기 위하여, 본 발명의 실시예에 따른 자동차 노킹 센서용 비연계 압전체의 제조 방법에 있어서, (Na2CO3 또는 K2CO3) 및 Nb2O5를 원료로서 혼합하여 제1 혼합물을 형성하고, 상기 제1 혼합물을 이용하여 제1 밀링 공정 및 제2 건조 공정을 통하여 제1 분말을 형성한다. 상기 제1 분말을 하소하여 (Na1-xKx)NbO3 분말(여기서, x는 0.5 또는 1임)을 형성하고, 상기 (Na1-xKx)NbO3 분말에 z mol%의 첨가제 CuO(여기서, 0.5≤z≤2.0 임)를 첨가하여 제2 혼합물을 형성한다. 이후, 상기 제2 혼합물을 이용하여 제2 밀링 공정 및 제2 건조 공정을 통하여 제2 분말을 형성하고, 상기 제2 분말을 940 내지 980℃의 온도에서 소결하여 소결체를 형성한다.In order to achieve another object of the present invention, in the method for manufacturing a non-connected piezoelectric material for a vehicle knocking sensor according to an embodiment of the present invention, (Na 2 CO 3 or K 2 CO 3 ) and Nb 2 O 5 are mixed as raw materials to form a first mixture, and the first mixture is formed using a first milling process and a second drying process using the first mixture. The first powder was calcined to form (Na 1-x K x ) NbO 3 powder, where x is 0.5 or 1, and z mol% of additives to the (Na 1-x K x ) NbO 3 powder CuO, where 0.5 ≦ z ≦ 2.0, is added to form a second mixture. Thereafter, a second powder is formed through the second milling process and the second drying process using the second mixture, and the second powder is sintered at a temperature of 940 to 980 ° C to form a sintered body.
본 발명의 일 실시예에 있어서, 상기 제1 밀링 공정은 상기 제1 혼합물을 나일론 자르(nylon jar)에 무수 알콜 용매와 함께 넣고 지르코니아 볼을 사용하여 2시간 내지 24시간동안 분쇄할 수 있다. In one embodiment of the present invention, the first milling process may be put in a nylon jar (nylon jar) with anhydrous alcoholic solvent can be crushed for 2 to 24 hours using a zirconia ball.
본 발명의 일 실시예에 있어서, 상기 제2 밀링 공정은 상기 제2 혼합물을 나일론 자르(nylon jar)에 무수 알콜 용매와 함께 넣고 지르코니아 볼을 사용하여 48시간 내지 72시간 동안 분쇄할 수 있다. In one embodiment of the present invention, the second milling process may be put into a nylon jar (nylon jar) with anhydrous alcoholic solvent and pulverized for 48 to 72 hours using a zirconia ball.
본 발명의 일 실시예에 있어서, 상기 제2 분말을 소결하여 소결체를 형성하는 공정은 2시간 내지 20시간 동안 수행될 수 있다.In one embodiment of the present invention, the process of sintering the second powder to form a sintered body may be performed for 2 to 20 hours.
상술한 본 발명의 실시예들에 따른 자동차 노킹 센서용 비연계 압전체 및 이의 제조 방법에 따르면, CuO가 첨가되며 납(Pb)이 첨가되지 않아, 환경문제를 억제할 수 있다. 나아가, 상대적으로 간단한 공정을 통하여 비연계 압전체가 제조될 수 있다. 특히, 1,000℃보다 낮은 온도에서 저온 소결 공정이 가능함에 따라 Na2O 및 K2O의 휘발이 억제됨으로써 균일한 조성을 갖는 비연계 압전체가 제조될 수 있다. 나아가, CuO가 첨가된 비연계 압전체는 우수한 압전 특성 및 유전 특성을 구현할 수 있다. 특히 상술한 본 발명의 실시예들에 따른 비연계 압전체는 자동차용 노킹 센서를 비롯한 각종 진동 센서에 적합하도록 상대적으로 높은 압전 전압 상수(g33)값, 품질계수(Qm)값 및 높은 상전이 온도(Tc)값을 가짐에 따라 비연계 압전 센서에 활용이 가능하다.According to the non-connected piezoelectric piezoelectric sensor for automobile knocking sensor and the manufacturing method thereof according to the embodiments of the present invention described above, CuO is added and lead (Pb) is not added, thereby preventing environmental problems. Furthermore, the non-connected piezoelectric body can be manufactured through a relatively simple process. In particular, as the low-temperature sintering process is possible at a temperature lower than 1,000 ° C., volatilization of Na 2 O and K 2 O is suppressed, thereby making a non-connected piezoelectric body having a uniform composition. Furthermore, the non-connected piezoelectric element to which CuO is added can implement excellent piezoelectric and dielectric properties. In particular, the non-connected piezoelectric body according to the embodiments of the present invention described above has a relatively high piezoelectric voltage constant (g 33 ) value, quality coefficient (Q m ) value, and high phase transition temperature to be suitable for various vibration sensors including a knocking sensor for a vehicle. With (T c ) value, it can be used for non-connected piezoelectric sensor.
도 1은 본 발명의 실시예들에 따른 자동차 노킹 센서용 비연계 압전체의 제조 방법을 설명하기 위한 순서도이다.1 is a flowchart illustrating a method of manufacturing a non-connected piezoelectric material for a vehicle knocking sensor according to embodiments of the present invention.
도 2는 소결 온도의 변화에 따른 CuO가 첨가된 NKN압전체의 상대 밀도, 유전 특성 및 압전 특성 변화를 나타낸 그래프이다.FIG. 2 is a graph showing changes in relative density, dielectric properties, and piezoelectric properties of CuO-added NKN piezoelectric bodies with sintering temperature.
도 3은 960℃에서 2.0 시간 소결된 CuO가 첨가된 KN 압전체에 대하여 CuO 첨가량의 변화에 따른 미세 구조를 보여주는 전자 주사 현미경 사진들이다.3 are electron scanning micrographs showing the microstructure of the KN piezoelectric body added with CuO sintered at 960 ° C. for 2.0 hours according to the change of CuO addition amount.
도 4는 960℃에서 2.0 시간 소결된 CuO가 첨가된 KN 압전체의 상대밀도, 유전 특성 및 압전 특성 변화를 나타낸 그래프이다.4 is a graph showing changes in relative density, dielectric properties, and piezoelectric properties of a KN piezoelectric body added with CuO sintered at 960 ° C. for 2.0 hours.
도 5는 960℃에서 2.0 시간 소결된 CuO가 첨가된 NKN 압전체(실시예1)를 이용하여 제조된 녹킹(knocking) 센서 및 PZT(기존 상용품, 비교예)를 이용한 자동차 노킹 센서의 센서 감도 특성들을 나타낸 그래프이다.5 is a sensor sensitivity characteristics of a knocking sensor manufactured using an NKN piezoelectric material (Example 1) added with CuO sintered at 960 ° C. for 2.0 hours and a vehicle knocking sensor using PZT (existing commercially available, comparative example). This is a graph.
본 발명의 실시예에 따른 자동차 노킹 센서용 비연계 압전체는 (Na1-xKx)NbO3; 및 z mol%의 첨가제 CuO를 포함하고, 940 내지 980℃의 소결 온도에서 형성된다. 여기서, x는 0.5 또는 1이며, 0.5≤z≤2.0 이다.Non-connected piezoelectric for automotive knock sensor according to an embodiment of the present invention (Na 1-x K x ) NbO 3 ; And z mol% of additive CuO, and is formed at a sintering temperature of 940 to 980 ° C. Here, x is 0.5 or 1 and 0.5 <= z <= 2.0.
이하, 첨부한 도면을 참조하여 본 발명의 실시예들에 대해 상세히 설명한다. 본 발명은 다양한 변경을 가할 수 있고 여러 가지 형태를 가질 수 있는 바, 특정 실시예들을 도면에 예시하고 본문에 상세하게 설명하고자 한다. 그러나, 이는 본 발명을 특정한 개시 형태에 대해 한정하려는 것이 아니며, 본 발명의 사상 및 기술 범위에 포함되는 모든 변경, 균등물 내지 대체물을 포함하는 것으로 이해되어야 한다. 첨부된 도면에 있어서, 대상물들의 크기와 양은 본 발명의 명확성을 기하기 위하여 실제보다 확대 또는 축소하여 도시한 것이다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In the accompanying drawings, the size and amount of the objects are shown to be enlarged or reduced than actual for clarity of the invention.
제1, 제2 등의 용어는 다양한 구성요소들을 설명하는데 사용될 수 있지만, 상기 구성요소들은 상기 용어들에 의해 한정되어서는 안 된다. 상기 용어들은 하나의 구성요소를 다른 구성요소로부터 구별하는 목적으로만 사용된다. 예를 들어, 본 발명의 권리 범위를 벗어나지 않으면서 제1 구성요소는 제2 구성요소로 명명될 수 있고, 유사하게 제2 구성요소도 제1 구성요소로 명명될 수 있다.Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.
본 출원에서 사용한 용어는 단지 특정한 실시예를 설명하기 위해 사용된 것으로, 본 발명을 한정하려는 의도가 아니다. 단수의 표현은 문맥상 명백하게 다르게 뜻하지 않는 한, 복수의 표현을 포함한다. 본 출원에서, "포함하다" 또는 "구비하다" 등의 용어는 명세서 상에 기재된 특징, 단계, 기능, 구성요소 또는 이들을 조합한 것이 존재함을 지정하려는 것이지, 다른 특징들이나 단계, 기능, 구성요소 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다.The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "include" are intended to indicate that there is a feature, step, function, component, or combination thereof described on the specification, and other features, steps, functions, components Or it does not exclude in advance the possibility of the presence or addition of them in combination.
한편, 다르게 정의되지 않는 한, 기술적이거나 과학적인 용어를 포함해서 여기서 사용되는 모든 용어들은 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자에 의해 일반적으로 이해되는 것과 동일한 의미를 가지고 있다. 일반적으로 사용되는 사전에 정의되어 있는 것과 같은 용어들은 관련 기술의 문맥 상 가지는 의미와 일치하는 의미를 가지는 것으로 해석되어야 하며, 본 출원에서 명백하게 정의하지 않는 한, 이상적이거나 과도하게 형식적인 의미로 해석되지 않는다.On the other hand, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.
비연계 압전체Non-connected piezoelectric
본 발명의 실시예들에 따른 자동차 노킹 센서용 비연계 압전체는 (Na1-xKx)NbO3 및 z mol%의 첨가제 CuO를 포함한다. 여기서, x는 0.5 또는 1이며, 0.5≤z≤2.0의 범위를 갖는다. 즉, x가 0.5일 경우, 비연계 압전체는 (Na0.5K0.5)NbO3를 포함하므로, NKN 계열의 압전체에 해당하며, x가 1일 경우, KNbO3를 포함하므로, KN 계열의 압전체에 해당한다.Non-connected piezoelectric for automotive knocking sensor according to embodiments of the present invention includes (Na 1-x K x ) NbO 3 and z mol% of additive CuO. Here, x is 0.5 or 1 and has a range of 0.5 ≦ z ≦ 2.0. That is, when x is 0.5, the non-connected piezoelectric material includes (Na 0.5 K 0.5 ) NbO 3, and thus, corresponds to the NKN-based piezoelectric material. When x is 1, KNbO 3 is included, so the non-connected piezoelectric material includes (N 0.5 K 0.5 ) NbO 3 . do.
상기 첨가제는 CuO를 포함한다. 상기 첨가제는 상기 비연계 압전체를 제조하는 소결 공정 중 (Na1-xKx)NbO3 와 반응하여 중간체를 형성하고 상기 중간체는 상대적으로 낮은 녹는점을 가짐에 따라 감소된 소결 온도에서 액상 소결 공정이 진행될 수 있도록 한다. 즉, 940 내지 980℃의 소결 온도에서 상기 소결 공정이 진행될 수 있다. 이로써, 상기 감소된 소결 온도에서 소결 공정이 진행됨에 따라, Na2O 및 K2O의 휘발이 억제됨으로써 균일한 조성을 갖는 비연계 압전체가 제조될 수 있다. 또한, CuO가 첨가된 비연계 압전체는 우수한 압전 특성 및 유전 특성을 구현할 수 있다.The additive includes CuO. The additive reacts with (Na 1-x K x ) NbO 3 to form an intermediate in the sintering process of manufacturing the non-connected piezoelectric body, and the intermediate has a relatively low melting point, thereby liquid phase sintering at a reduced sintering temperature. Allow this to proceed. That is, the sintering process may be performed at a sintering temperature of 940 to 980 ° C. Thus, as the sintering process proceeds at the reduced sintering temperature, volatilization of Na 2 O and K 2 O is suppressed, thereby making a non-connected piezoelectric body having a uniform composition. In addition, the non-connected piezoelectric element to which CuO is added may implement excellent piezoelectric and dielectric properties.
비연계 압전체의 제조 방법Manufacturing method of non-connected piezoelectric body
도 1은 본 발명의 실시예들에 따른 자동차 노킹 센서용 비연계 압전체의 제조 방법을 설명하기 위한 순서도이다.1 is a flowchart illustrating a method of manufacturing a non-connected piezoelectric material for a vehicle knocking sensor according to embodiments of the present invention.
도 1을 참조하면, (Na2CO3 또는 K2CO3) 및 Nb2O5을 원료로서 혼합하여 제1 혼합물을 형성한다.(S110) Referring to Figure 1, (Na 2 CO 3 or K 2 CO 3 ) and Nb 2 O 5 are mixed as raw materials to form a first mixture. (S110)
상기 제1 혼합물의 조성에 따라 순도 99%이상의 (Na2CO3 또는 K2CO3) 및 Nb2O5 를 질량 비율을 계산하는 배치(Batch) 공정을 수행한 후, 배치(Batch) 결과에 따른 각각의 무게를 평량(Weighing)하는 평량 공정을 수행한다. 이후, 상기 배치 공정 및 평량 공정에 따라 그 양에 따라 (Na2CO3 또는 K2CO3) 및 Nb2O5을 혼합하여 제1 혼합물을 형성한다. 즉, Na2CO3 , K2CO3 및 Nb2O5을 혼합하여 제1 혼합물을 형성할 경우, NKN 계열의 압전체가 형성되는 반면에, K2CO3 및 Nb2O5을 혼합하여 제1 혼합물을 형성할 경우, KN 계열의 압전체가 형성될 수 있다.Depending on the composition of the first mixture of purity of 99% or more (Na 2 CO 3 K 2 CO 3 ) and Nb 2 O 5 are subjected to a batch process for calculating the mass ratio, and then a basis weight process for weighing each weight according to the batch results is performed. Then, according to the batch process and basis weight process according to the amount (Na 2 CO 3 or K 2 CO 3 ) and Nb 2 O 5 are mixed to form a first mixture. That is, when Na 2 CO 3, K 2 CO 3 and Nb 2 O 5 are mixed to form a first mixture, an NKN series piezoelectric body is formed, while K 2 CO 3 and Nb 2 O 5 are mixed to form a first mixture. When forming a mixture, a KN series piezoelectric body may be formed.
이후, 상기 제1 혼합물을 이용하여 제1 밀링 공정 및 제2 건조 공정을 통하여 제1 분말을 형성한다.(S120)Thereafter, the first mixture is used to form a first powder through a first milling process and a second drying process (S120).
상기 제1 밀링 공정에 있어서, 나일론 자르(nylon jar)에서 지르코니아 볼과 함께 2 ~ 24시간동안 무수 알코올 용매를 사용하여 습식 혼합한 후 파우더로 분쇄하는 제1 볼-밀링(First ball-milling) 공정이 수행될 수 있다. 이어서, 제1 볼-밀링 공정에서 혼합된 무수 알코올을 제거하는 건조(Drying) 공정이 수행됨에 따라 파우더 형태의 제1 분말이 형성된다.In the first milling process, a first ball-milling process of wet mixing using anhydrous alcohol solvent for 2 to 24 hours with a zirconia ball in a nylon jar and grinding it into powder This can be done. Subsequently, a drying process of removing the mixed anhydrous alcohol in the first ball-milling process is performed to form a first powder in powder form.
이후, 상기 제1 분말을 하소하여 (Na1-xKx)NbO3 분말(여기서, x는 0.5 또는 1임)을 형성한다.(S130)Thereafter, the first powder is calcined to form (Na 1-x K x ) NbO 3 powder, where x is 0.5 or 1. (S130)
여기서, x가 0.5일 경우, 비연계 압전체는 (Na0.5K0.5)NbO3를 포함하므로, NKN 계열의 압전체에 해당하며, x가 1일 경우, KNbO3를 포함하므로, KN 계열의 압전체에 해당한다. 여기서 하소(Calcination) 공정은 800 ~ 1000℃에서 2 ~ 10시간 동안 수행될 수 있다.Herein, when x is 0.5, the non-connected piezoelectric material includes (Na 0.5 K 0.5 ) NbO 3, and thus, corresponds to the NKN-based piezoelectric material, and when x is 1, KNbO 3 is included and thus corresponds to the KN-based piezoelectric material. do. Here, the calcination process may be performed at 800 to 1000 ° C. for 2 to 10 hours.
상기 (Na1-xKx)NbO3 분말에 z mol%의 첨가제 CuO를 첨가하여 제2 혼합물을 형성한다.(S140) 여기서, 0.5≤z≤2.0 이다. Z mol% of additive CuO is added to the (Na 1-x K x ) NbO 3 powder to form a second mixture. (S140) Here, 0.5 ≦ z ≦ 2.0.
상기 첨가제는 후속하는 소결 공정 중 (Na1-xKx)NbO3 와 반응하여 중간체를 형성하고 상기 중간체는 상대적으로 낮은 녹는점을 가짐에 따라 감소된 소결 온도에서 액상 소결 공정이 진행될 수 있도록 한다. 즉, 940 내지 980℃의 소결 온도에서 상기 소결 공정이 진행될 수 있다. 이로써, 상기 감소된 소결 온도에서 소결 공정이 진행됨에 따라, Na2O 및 K2O의 휘발이 억제됨으로써 균일한 조성을 갖는 비연계 압전체가 제조될 수 있다. 또한, CuO가 첨가된 비연계 압전체는 우수한 압전 특성 및 유전 특성을 구현할 수 있다.The additive reacts with (Na 1-x K x ) NbO 3 to form an intermediate during the subsequent sintering process and allows the liquid phase sintering process to proceed at a reduced sintering temperature as the intermediate has a relatively low melting point. . That is, the sintering process may be performed at a sintering temperature of 940 to 980 ° C. Thus, as the sintering process proceeds at the reduced sintering temperature, volatilization of Na 2 O and K 2 O is suppressed, thereby making a non-connected piezoelectric body having a uniform composition. In addition, the non-connected piezoelectric element to which CuO is added may implement excellent piezoelectric and dielectric properties.
이어서, 상기 제2 혼합물을 이용하여 제2 밀링 공정 및 제2 건조 공정을 통하여 제2 분말을 형성한다.(S150)Subsequently, a second powder is formed through the second milling process and the second drying process using the second mixture.
여기서, 상기 제2 밀링 공정에 따르면, (Na1-xKx)NbO3 및 CuO로 이루어진 제2 분말에 무수 알콜 용매로 48 ~ 72시간 습식 혼합하고, 지르코니아 볼을 이용하여 분쇄하는 제2 볼-밀링(Second ball-milling) 공정이 수행될 수 있다. 이이서, 상기 제2 볼-밀링 공정에 이용된 무수 알콜 용매를 제거하는 건조 공정이 수행될 수 있다. 이로써 CuO가 첨가제로 첨가된 NKN 및 KN 계열의 제2 분말이 형성된다.Here, according to the second milling process, the second powder is wet-mixed for 48 to 72 hours with anhydrous alcohol solvent to the second powder consisting of (Na 1-x K x ) NbO 3 and CuO, and crushed using a zirconia ball -Second ball-milling process can be performed. Next, a drying process may be performed to remove the anhydrous alcoholic solvent used in the second ball-milling process. As a result, NKN and KN-based second powder to which CuO was added as an additive is formed.
이어서, 940 ~ 980℃에서 상기 제2 분말을 소결(Sintering) 하여 소결체를 형성하는 소결 공정이 수행된다.(S160) Subsequently, a sintering process of sintering the second powder at 940 to 980 ° C. to form a sintered body is performed.
상기 소결체는 음파 기기, 영상기기, 음향기기, 통신기기, 센서, 초음파 진동자, 전기기계 트랜스듀서(transducer) 또는 액추에이터(actuator)에 사용되는 압전체로 다양한 형태와 크기를 가질 수 있다. The sintered body may be a piezoelectric material used in a sound wave device, an imaging device, an audio device, a communication device, a sensor, an ultrasonic vibrator, an electromechanical transducer, or an actuator, and may have various shapes and sizes.
본 발명의 일 실시예에 있어서, 상기 소결 공정 이전에, 상기 제2 분말을 균질한 사이즈로 걸러내는 선별(Sieving) 공정 및 걸러진 분말을 특정 형상을 갖도록 가압 성형(Pressing) 공정이 선행적으로 수행될 수 있다. 일 예로서, 상기 소결체는 실린더 모양 또는 링 형상을 가질 수 있도록 가압 성형될 수 있다.In one embodiment of the present invention, prior to the sintering process, a sieving process for filtering the second powder into a homogeneous size and a pressing process for performing the filtered powder to have a specific shape are performed in advance. Can be. As an example, the sintered body may be press-molded to have a cylinder shape or a ring shape.
본 발명의 일 실시예에 있어서, 소결체에 대하여 후처리(post-treatment) 공정이 추가적으로 수행될 수 있다. 상기 후처리 공정에 따르면, 상기 소결체를 연마한 후, 상기 소결체의 표면에 전극 물질을 도포하고 실리콘 오일 속에 담그고 120 ~ 150℃ 온도에서 3 ~ 5kV/mm DC 바이어스가 1시간 동안 인가될 수 있다.In one embodiment of the present invention, a post-treatment process may be additionally performed on the sintered body. According to the post-treatment process, after polishing the sintered body, an electrode material is applied to the surface of the sintered body and immersed in silicon oil, and a 3 to 5 kV / mm DC bias may be applied for 1 hour at a temperature of 120 to 150 ° C.
비연계 압전체의 평가Evaluation of non-connected piezoelectric
초기 원료인 순도 99.9%의 Na2CO3,K2CO3및 Nb2O5를 혼합하여 나일론 자르(nylon jar)에서 지르코니아 볼과 함께 24시간동안 무수 알콜 용매를 사용하여 습식 혼합하여 제1 혼합물을 형성하였다. The first mixture by mixing Na 2 CO 3 , K 2 CO 3 and Nb 2 O 5 , which is an initial raw material with a purity of 99.9%, and wet mixing with zirconia balls in a nylon jar using anhydrous alcoholic solvent for 24 hours. Formed.
이어서, 제1 혼합물을 건조 시킨 후 950℃에서 3시간 동안 하소하여 (Na0.5K0.5)NbO3(제1 실시예) 및 KNbO3(제2 실시예)분말을 합성하여 제1 분말을 제조하였다. 제1 분말에 0.5 ~ 5.0 mol%의 CuO를 첨가하여, 72시간동안 무수 알콜 용매를 사용해 습식 혼합 및 분쇄한 후 건조하여 제2 혼합물을 형성하였다. 이어서, 건조된 분말을 직경이 18mm, 높이가 약 1.3 ~ 1.5mm인 실린더 형상의 성형체로 가압 성형 후 960℃에서 2시간 동안 소결하여 소결체를 형성하였다.Subsequently, the first mixture was dried and then calcined at 950 ° C. for 3 hours to synthesize (Na 0.5 K 0.5 ) NbO 3 (Example 1) and KNbO 3 (Example 2) powders to prepare a first powder. . 0.5-5.0 mol% of CuO was added to the first powder, wet mixed and pulverized with anhydrous alcoholic solvent for 72 hours, and then dried to form a second mixture. Subsequently, the dried powder was sintered at 960 ° C. for 2 hours after pressure molding into a cylindrical shaped body having a diameter of 18 mm and a height of about 1.3 to 1.5 mm to form a sintered body.
상기 소결체를 연마하고, 전극 물질을 도포한 후에 실리콘 오일 속에서 120 ~ 150℃ 온도에서 3 ~ 5kV/mm DC 바이어스를 1시간 동안 가한 후 24시간 지난 후에 특성을 측정하였다. After the sintered body was polished and the electrode material was applied, the characteristics were measured after 24 hours after applying a 3-5 kV / mm DC bias for 1 hour at 120-150 ° C. in a silicone oil.
도 2는 소결 온도의 변화에 따른 CuO가 첨가된 NKN압전체(실시예1)의 상대 밀도, 유전 특성 및 압전 특성 변화를 나타낸 그래프이다.FIG. 2 is a graph showing changes in relative density, dielectric properties, and piezoelectric properties of NKN piezoelectric material (Example 1) to which CuO is added according to a change in sintering temperature.
도 2를 참조하면, 1,000℃이상의 저온에서도 높은 소결 밀도를 가지는 것을 알 수 있다. 단, 소결 온도가 1,000℃에 근접하게 되면 상대 밀도가 서서히 감소하게 되는데 이는 지나치게 많은 액상 형성에 의한 것에 의한 것이다. 나트륨(Na)의 휘발이 억제 되었으므로 CuO가 첨가된 NKN 압전체는 Cu-Nb반응에 의한 액상 소결 거동이 발생한 것이다. 또한, 상대 밀도가 줄어듦에 따라 다른 압전 및 유전 특성도 서서히 감소한다. 즉, 상기와 같은 제조 방법을 따라, 960℃의 낮은 온도에서 소결되며 CuO가 1.5mol% 첨가된 KN 압전체는 g33=55Vm/N, kp=0.4, 3 T/0=195, Qm=880의 우수한 압전 특성을 가짐을 확인할 수 있다.2, it can be seen that it has a high sintered density even at a low temperature of 1,000 ° C or more. However, when the sintering temperature approaches 1,000 ° C, the relative density gradually decreases due to the formation of too much liquid phase. Since the volatilization of sodium (Na) was suppressed, the NKN piezoelectric material containing CuO generated liquid phase sintering behavior by Cu-Nb reaction. In addition, as the relative density decreases, other piezoelectric and dielectric properties gradually decrease. That is, according to the manufacturing method described above, the KN piezoelectric body sintered at a low temperature of 960 ° C. and added 1.5 mol% of CuO g 33 = 55 Vm / N, kp = 0.4, 3 T / 0 = 195, Q m = 880 It can be confirmed that has excellent piezoelectric properties.
도 3은 960℃에서 2.0 시간 소결된 CuO가 첨가된 KN 압전체(실시예2)에 대하여 CuO 첨가량의 변화에 따른 미세 구조를 보여주는 전자 주사 현미경 사진들이다.3 are electron scanning micrographs showing the microstructure of the KN piezoelectric body (Example 2) added with CuO sintered at 960 ° C. for 2.0 hours according to the change of CuO addition amount.
도 3을 참조하면, CuO가 첨가되지 않은 경우에는 소결 정도가 너무 낮아서 현미경 사진을 찍을 수 없다. (a)에서 보여 주듯이 매우 소량(0.5 mol%)의 CuO가 첨가된 경우에는 치밀화가 일어나지만 액상의 양이 충분하지 않아 입도 성장은 일어나지 않는 것을 알 수 있다. 하지만 (b)를 살펴보면, 1.0 mol%의 CuO가 첨가된 경우에는 기공이 거의 없는 치밀한 미세구조가 형성됨을 알 수 있으며,화살표로 나타냈듯이 입도 성장도 일부 나타났다.Referring to Figure 3, when CuO is not added, the degree of sintering is too low to take a micrograph. As shown in (a), when a very small amount (0.5 mol%) of CuO is added, densification occurs, but the amount of liquid phase is insufficient, so that no grain size growth occurs. However, looking at (b), when 1.0 mol% of CuO is added, it can be seen that a dense microstructure with almost no pores is formed. As shown by the arrow, the grain size growth is also partially shown.
또한, (c)와 (d)를 보면, CuO 양이 2.0 mol% 이상으로 증가하면 치밀한 미세 구조가 형성되며, 대부분의 입도가 크게 성장됨을 확인할 수 있다. In addition, looking at (c) and (d), when the amount of CuO increases to 2.0 mol% or more, a dense microstructure is formed, and it can be seen that most of the grain size is greatly increased.
도 4는 960℃에서 2.0 시간 소결된 CuO가 첨가된 KN 압전체(실시예2)의 상대 밀도, 유전 특성 및 압전 특성 변화를 나타낸 그래프이다.4 is a graph showing changes in relative density, dielectric properties, and piezoelectric properties of a KN piezoelectric body (Example 2) added with CuO sintered at 960 ° C. for 2.0 hours.
도 4를 참조하면, 960℃에서 CuO를 첨가하지 않은 시료는 소결이 되지 않아서 상대 밀도가 매우 낮지만, 0.5 mol%의 소량 CuO만 첨가 되어도 KN 압전체의 액상 소결이 발생하여 상대 밀도가 이론 밀도의 95.5% 달한다. KN 압전체의 압전 변형 상수(d33), 압전 전압 상수(g33) 및 유전율과 전기 기계 결합 상수(Kp)는 CuO첨가량에 따라서 서서히 감소하는 경향을 인다. Referring to FIG. 4, the sample without CuO at 960 ° C. is not sintered so that the relative density is very low. However, even when only 0.5 mol% of CuO is added, the liquid phase sintering of the KN piezoelectric body generates a relative density of theoretical density. 95.5%. The piezoelectric strain constant (d 33 ), piezoelectric voltage constant (g 33 ), and dielectric constant and electromechanical coupling constant (K p ) of the KN piezoelectric tend to decrease gradually with the addition amount of CuO.
반면에 기계적 품질계수(Qm)는 CuO첨가에 따라 급격하게 증가한다. 이는 Cu 일부가 KN으로 고용됨으로써 생기는 Hardening Effect로 설명할 수 있다.특히, 1.5 mol%의 CuO가 첨가된 시편의 경우는 2,300의 높은 Qm을 나타내었다. 뿐만 아니라,이로 인한 낮은 유전율 때문에 압전 전압 상수(g33)가 44 Vm/N의 높은 값을 가진다. 상기 압전 전압 상수는 지금까지 알려진 비연 세라믹 압전체 중에서 가장 높은 값으로, 진동 센서의 한 종류인 자동차용 노킹센서에 충분히 적용이 가능함을 알 수 있다.On the other hand, the mechanical quality factor (Q m ) increases rapidly with the addition of CuO. This can be explained by the hardening effect caused by the solid solution of Cu as KN. Particularly, the specimen with 1.5 mol% CuO showed high Q m of 2,300. In addition, because of the low dielectric constant, the piezoelectric voltage constant g 33 has a high value of 44 Vm / N. The piezoelectric voltage constant is the highest value of the non-lead ceramic piezoelectric material known so far, and it can be understood that the piezoelectric voltage constant can be sufficiently applied to a knocking sensor for a vehicle, which is a type of vibration sensor.
결과적으로 자동차 노킹 센서와 같은 압전 진동 센서에 필요한 압전 전압 상수와 기계적 품질 계수 및 전기 기계 결합 계수를 종합적으로 판단하였을 때, 1.0 mol%의 CuO를 첨가할 경우, 각각의 높은 압전 특성을 얻을 수 있다. 즉, 상기와 같은 제조 방법을 따라, 960℃의 낮은 온도에서 소결된 CuO가 1.0mol% 첨가된 KN 압전체는 g33=48 Vm/N, kp=0.27,3 T/0=208, Qm=1787의 우수한 압전 특성을 가짐을 확인할 수 있다.As a result, when the piezoelectric voltage constants, mechanical quality coefficients, and electromechanical coupling coefficients required for piezoelectric vibration sensors such as automobile knocking sensors are comprehensively determined, the addition of 1.0 mol% of CuO provides high piezoelectric characteristics. . That is, according to the manufacturing method described above, KN piezoelectric body added 1.0 mol% of CuO sintered at a low temperature of 960 ° C., g 33 = 48 Vm / N, kp = 0.27, 3 T / 0 = 208, Q m = It can be seen that the 1787 has excellent piezoelectric properties.
도 5는 960℃에서 2.0 시간 소결된 CuO가 첨가된 NKN 압전체(실시예1)를 이용하여 제조된 자동차 노킹(knocking) 센서 및 PZT(기존 상용품, 비교예)를 이용한 녹킹 센서의 센서 감도 특성들을 나타낸 그래프이다.5 is a sensor sensitivity characteristics of a knocking sensor using a vehicle knocking sensor prepared using NKN piezoelectric material (Example 1) added CuO sintered at 960 ° C. for 2.0 hours and PZT (existing commercially available, comparative example). This is a graph.
도 5를 참조하면, Knocking 센서에 쓰이는 주파수인 1~20kHz대역에서 2.0 시간 소결된 CuO가 첨가된 NKN 압전체(실시예1)가 기존 상용품 대비 1.5배 이상의 높은 센서 감도를 가지는 것을 알 수 있다. 이러한 높은 센서 감도는 비연 압전체의 우수한 압전 전압 상수(g33)에 기인한 것을 알 수 있다. 따라서 CuO가 첨가된 NKN 및 KN 세라믹스는 비연압전 자동차 노킹 센서 및 기타 진동 센서로 충분히 활용이 가능함을 알 수 있다.Referring to FIG. 5, it can be seen that the NKN piezoelectric (Example 1) added with CuO sintered for 2.0 hours in a band of 1 to 20 kHz, which is a frequency used for knocking sensors, has a sensor sensitivity that is 1.5 times higher than that of conventional commercial products. It can be seen that this high sensor sensitivity is due to the excellent piezoelectric voltage constant g33 of the non-lead piezoelectric body. Therefore, it can be seen that NKN and KN ceramics added with CuO can be sufficiently utilized as non-pneumatic car knocking sensors and other vibration sensors.
나아가, 상기 실시예 1 (Na0.5K0.5)NbO3 [NKN]+ 1.5 mol% CuO), 실시예 2 (KNbO3 [KN]+ 1.0 mol% CuO) 및 비교예(P-6CTM, Murata 社)에 대한 유전 특성 및 압전 특성은 아래의 표로 정리한다.Furthermore, Example 1 (Na 0.5 K 0.5 ) NbO 3 [NKN] + 1.5 mol% CuO), Example 2 (KNbO 3 [KN] + 1.0 mol% CuO) and Comparative Example (P-6C ™ , Murata Co., Ltd.) Dielectric properties and piezoelectric properties for) are summarized in the table below.
표 1
구분 g33(Vm/N) d33(pC/N) 비유전율 Qm Kp 소결온도(℃) 전이온도(℃)
실시예1 55 95 195 880 0.4 960 406
실시예2 48 88 208 1787 0.27 960 430
실시예3 19 135 800 680 0.39 - 320
Table 1
division g 33 (Vm / N) d 33 (pC / N) Relative dielectric constant Qm Kp Sintering Temperature (℃) Transition temperature (℃)
Example 1 55 95 195 880 0.4 960 406
Example 2 48 88 208 1787 0.27 960 430
Example 3 19 135 800 680 0.39 - 320
실시예1 및 실시예2의 경우, 비교예보다 진동 센서에 적합한 우수한 압전 특성을 가지는 것을 알 수 있다. 특히, 진동 센서의 감도에 직접적인 영향을 주는 압전 전압 상수가 월등이 높음을 확인할 수 있다.In the case of Example 1 and Example 2, it can be seen that it has superior piezoelectric properties suitable for the vibration sensor than the comparative example. In particular, it can be seen that the piezoelectric voltage constant which directly affects the sensitivity of the vibration sensor is high.
본 발명의 실시예들에 따른 비연계 압전체는 첨가제(CuO)양을 조절하여 진동 센서, 특히 자동차용 노킹 센서 생산에 바로 적용할 수 있다.The non-connected piezoelectric body according to the embodiments of the present invention can be directly applied to the production of vibration sensors, particularly knocking sensors for automobiles by adjusting the amount of additive (CuO).
상기에서는 본 발명의 바람직한 실시예를 참조하여 설명하였지만, 해당 기술 분야의 숙련된 당업자는 하기의 특허 청구 범위에 기재된 본 발명의 사상 및 영역으로부터 벗어나지 않는 범위 내에서 본 발명을 다양하게 수정 및 변경시킬 수 있음을 이해할 수 있을 것이다.While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (7)

  1. (Na1-xKx)NbO3; 및(Na 1-x K x ) NbO 3 ; And
    z mol%의 첨가제 CuO를 포함하고, 940 내지 980℃의 소결 온도에서 형성되는 자동차 노킹 센서용 비연계 압전체.(여기서, x는 0.5 또는 1이며, 0.5≤z≤2.0 임)A non-connected piezoelectric body for an automotive knock sensor comprising z mol% of additive CuO and formed at a sintering temperature of 940 to 980 ° C., where x is 0.5 or 1 and 0.5 ≦ z ≦ 2.0.
  2. (Na2CO3 또는 K2CO3) 및 Nb2O5를 원료로서 혼합하여 제1 혼합물을 형성하는 단계;(Na 2 CO 3 or K 2 CO 3 ) and Nb 2 O 5 as a raw material to form a first mixture;
    상기 제1 혼합물을 이용하여 제1 밀링 공정 및 제2 건조 공정을 통하여 제1 분말을 형성하는 단계;Forming a first powder through a first milling process and a second drying process using the first mixture;
    상기 제1 분말을 하소하여 (Na1-xKx)NbO3 분말(여기서, x는 0.5 또는 1임)을 형성하는 단계;Calcining the first powder to form a (Na 1-x K x ) NbO 3 powder, where x is 0.5 or 1;
    상기 (Na1-xKx)NbO3 분말에 z mol%의 첨가제 CuO(여기서, 0.5≤z≤2.0 임)를 첨가하여 제2 혼합물을 형성하는 단계; Adding z mol% of additive CuO, wherein 0.5 ≦ z ≦ 2.0, to the (Na 1-x K x ) NbO 3 powder to form a second mixture;
    상기 제2 혼합물을 이용하여 제2 밀링 공정 및 제2 건조 공정을 통하여 제2 분말을 형성하는 단계; 및Forming a second powder through a second milling process and a second drying process using the second mixture; And
    상기 제2 분말을 940 내지 980℃의 온도에서 소결하여 소결체를 형성하는 단계를 포함하는 자동차 노킹 센서용 비연계 압전체의 제조 방법.And sintering the second powder at a temperature of 940 to 980 ° C. to form a sintered body.
  3. 제2항에 있어서, 상기 제1 밀링 공정은 상기 제1 혼합물을 나일론 자르(nylon jar)에 무수 알콜 용매와 함께 넣고 지르코니아 볼을 사용하여 2시간 내지 24시간동안 분쇄하는 것을 특징으로 하는 자동차 노킹 센서용 비연계 압전체의 제조 방법.3. The vehicle knocking sensor according to claim 2, wherein the first milling process comprises placing the first mixture in a nylon jar with anhydrous alcoholic solvent and pulverizing for 2 to 24 hours using a zirconia ball. Method for producing a non-connected piezoelectric material for use.
  4. 제2항에 있어서, 상기 제2 밀링 공정은 상기 제2 혼합물을 나일론 자르(nylon jar)에 무수 알콜 용매와 함께 넣고 지르코니아 볼을 사용하여 48시간 내지 72시간 동안 분쇄하는 것을 특징으로 하는 자동차 노킹 센서용 비연계 압전체의 제조 방법.3. The vehicle knocking sensor according to claim 2, wherein the second milling process is carried out in a nylon jar with anhydrous alcoholic solvent and pulverized for 48 to 72 hours using a zirconia ball. Method for producing a non-connected piezoelectric material for use.
  5. 제2항에 있어서, 상기 제2 분말을 소결하여 소결체를 형성하는 단계는 2시간 내지 20시간 동안 수행되는 것을 특징으로 하는 자동차 노킹 센서용 비연계 압전체의 제조 방법.The method of claim 2, wherein the sintering of the second powder to form the sintered compact is performed for 2 hours to 20 hours.
  6. 제1항의 비연계 압전체를 포함하는 자동차 노킹 센서.An automotive knock sensor comprising the non-connected piezoelectric body of claim 1.
  7. 제2항 내지 제5항 중 어느 하나의 제조 방법을 이용하여 제조된 자동차 노킹 센서의 제조 방법.A method of manufacturing a vehicle knocking sensor manufactured using the manufacturing method of any one of claims 2 to 5.
PCT/KR2015/004011 2014-04-23 2015-04-22 Lead-free piezoelectric material for vehicle knock sensor, method for manufacturing same, and vehicle knock sensor comprising same WO2015163685A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117362034A (en) * 2023-11-10 2024-01-09 成都信息工程大学 Potassium sodium niobate-based piezoelectric ceramic with high mechanical quality factor and low-temperature preparation method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20090040089A (en) * 2007-10-19 2009-04-23 주식회사 이노칩테크놀로지 Piezoelectric material and method of manufacturing the same
KR20100033002A (en) * 2008-09-19 2010-03-29 (재)울산테크노파크 Composition of lead-free piezoelectric ceramics for ultrasonic vibrator
KR20100089651A (en) * 2009-02-04 2010-08-12 고려대학교 산학협력단 Composition of lead-free piezoelectric material and method for fabricating the same
KR20130008804A (en) * 2011-07-13 2013-01-23 한국기계연구원 Single crystal and fabrication process of (na,k)nbo3 based pb-free piezoelectric materials using solid state synthesis

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20090040089A (en) * 2007-10-19 2009-04-23 주식회사 이노칩테크놀로지 Piezoelectric material and method of manufacturing the same
KR20100033002A (en) * 2008-09-19 2010-03-29 (재)울산테크노파크 Composition of lead-free piezoelectric ceramics for ultrasonic vibrator
KR20100089651A (en) * 2009-02-04 2010-08-12 고려대학교 산학협력단 Composition of lead-free piezoelectric material and method for fabricating the same
KR20130008804A (en) * 2011-07-13 2013-01-23 한국기계연구원 Single crystal and fabrication process of (na,k)nbo3 based pb-free piezoelectric materials using solid state synthesis

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117362034A (en) * 2023-11-10 2024-01-09 成都信息工程大学 Potassium sodium niobate-based piezoelectric ceramic with high mechanical quality factor and low-temperature preparation method

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