JPH11217262A

JPH11217262A - Piezoelectric porcelain composition

Info

Publication number: JPH11217262A
Application number: JP10033604A
Authority: JP
Inventors: Atsushi Sasaki; 淳佐々木
Original assignee: Tokin Corp
Current assignee: Tokin Corp
Priority date: 1998-01-30
Filing date: 1998-01-30
Publication date: 1999-08-10

Abstract

PROBLEM TO BE SOLVED: To lower pollution because of a non-lead material used and remarkably improve mechanical quality coefficient Qm by adding a specific amount of Mn2 O3 , Co2 O3 , Fe2 O3 , NiO, Cr2 O3 , etc., to a piezoelectric porcelain composition comprising Bi, Na, K, Ti and O and having a specific composition. SOLUTION: This piezoelectric porcelain composition contains <=2 wt.% at least one or more kinds of Mn2 O3 , Co2 O3 , Fe2 O3 , NiO and Cr2 O3 in a piezoelectric porcelain composition represented by the general formula [Bi0.5 (Na1-x Kx )0.5 ]TiO3 [0<(x)<1]. The composition is obtained by stoichiometrically compounding Bi2 O3 , Na2 CO3 , TiO2 and K2 CO3 having high purity so as to have a prescribed composition and further adding prescribed amounts of Mn2 O3 , Fe2 O3 , NiO, Co2 O3 and Cr2 O3 thereto and mixing these components, calcining the mixture at about 800 deg.C, pulverizing the calcined material, granulating the resultant powder with a binder such as PVA, forming the granulated material under pressure and baking the formed product at about 1100 deg.C. Thereby, a composition excellent in piezoelectric characteristics and dielectric characteristics can be obtained using the non-lead material.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、波動デバイス、セ
ンサー、アクチュエーター等に用いられる圧電磁器組成
物に関する。[0001] The present invention relates to a piezoelectric ceramic composition used for a wave device, a sensor, an actuator and the like.

【０００２】[0002]

【従来の技術】従来、圧電磁器材料としては、二成分で
構成されるＰＺＴ（ＰｂＴｉＯ₃−ＰｂＺｒＯ₃）系や三
成分で構成されるＰＣＭ［ＰｂＴｉＯ₃−ＰｂＺｒＯ₃−
Ｐｂ（Ｍｇ_0.5Ｎｂ_0.5）ＴｉＯ₃］系磁器が主に用いら
れてきた。その理由としては、上記の材料が大きな圧電
性を示すことはもちろんであるが、それとともに、圧電
材料の用途は、センサー、アクチュエーター、フィルタ
ー等多種あり、各用途に要求される様々な特性に対し、
各成分量の割合を調整することにより、適宜に対応でき
るためである。2. Description of the Related Art Conventionally, piezoelectric ceramic materials include PZT (PbTiO ₃ -PbZrO ₃ ) composed of two components and PCM [PbTiO ₃ -PbZrO _3- composed of three components.
Pb (Mg _0.5 Nb _0.5 ) TiO ₃ ] -based porcelain has been mainly used. The reason for this is, of course, that the above materials exhibit large piezoelectric properties, but at the same time, piezoelectric materials are used in a variety of applications, such as sensors, actuators, and filters. ,
This is because the proportion of each component can be appropriately adjusted by adjusting the proportion of each component.

【０００３】しかし、これらの材料は、いずれも大変有
害な物質である鉛を主成分とするもので、原料比でいう
と、酸化鉛として６０ｗｔ％以上も含まれている。酸化
鉛は、仮焼、焼結等の製造時に、低温でも蒸発性が高
く、また、産業廃棄物中から溶出することも考えられ
る。しかし、この対策をするには、設備設置のため、膨
大な費用を投じなければならない。そこで、低公害化の
策として、無鉛材料で大きな圧電特性を示す材料が要望
されている。However, all of these materials contain lead, which is a very harmful substance, as a main component, and as a raw material ratio, contains as much as 60% by weight or more of lead oxide. Lead oxide has high evaporability even at low temperatures during production such as calcination and sintering, and may be eluted from industrial waste. However, taking this measure requires enormous costs for installing the equipment. Therefore, as a measure for reducing pollution, there is a demand for a lead-free material having a large piezoelectric characteristic.

【０００４】既存の無鉛圧電材料として、一般式［Ｂｉ
_0.5（Ｎａ_1-xＫ_x）_0.5］ＴｉＯ₃（但し、０＜ｘ＜１）
がある。この圧電材料では、機械的品質係数Ｑｍの値が
低く、高いＱｍが必要とされるフィルター、振動子等の
用途に適用することは困難であった。As an existing lead-free piezoelectric material, a general formula [Bi
_0.5 (Na _1-x K _x ) _0.5 ] TiO ₃ (where 0 <x <1)
There is. With this piezoelectric material, the value of the mechanical quality factor Qm is low, and it has been difficult to apply the piezoelectric material to applications such as filters and vibrators that require a high Qm.

【０００５】[0005]

【発明が解決しようとする課題】本発明は、無鉛で、高
いＱｍを有する圧電磁器組成物を提供することにある。An object of the present invention is to provide a piezoelectric ceramic composition which is lead-free and has a high Qm.

【０００６】[0006]

【課題を解決するための手段】本発明は、一般式［Ｂｉ
_0.5（Ｎａ_1-xＫ_x）_0.5］ＴｉＯ₃（但し、０＜ｘ＜１）
で表される圧電磁器組成物において、Ｍｎ₂Ｏ₃、Ｃｏ₂
Ｏ₃、Ｆｅ₂Ｏ₃、ＮｉＯ、Ｃｒ₂Ｏ₃の少なくとも１種以
上を２ｗｔ％以下含む圧電磁器組成物である。The present invention provides a compound represented by the general formula [Bi:
_0.5 (Na _1-x K _x ) _0.5 ] TiO ₃ (where 0 <x <1)
In the piezoelectric ceramic composition represented by the formula, Mn ₂ O ₃ , Co ₂
A piezoelectric ceramic composition containing at least one of O ₃ , Fe ₂ O ₃ , NiO, and Cr ₂ O _{3 in} an amount of 2 wt% or less.

【０００７】[0007]

【発明の実施の形態】所定の原料を、混合、仮焼、粉砕
する。その後、バインダー混合、造粒する。次に、成
形、焼成した後、電極を設け、分極する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Predetermined raw materials are mixed, calcined and pulverized. Thereafter, the binder is mixed and granulated. Next, after molding and firing, electrodes are provided and polarized.

【０００８】[0008]

【実施例】原料として、高純度であるＢｉ₂Ｏ₃、Ｎａ₂
ＣＯ₃、ＴｉＯ₂、Ｋ₂ＣＯ₃を用いた。これらを、一般式
［Ｂｉ_0.5（Ｎａ_1-xＫ_x）_0.5］ＴｉＯ₃（０＜ｘ＜１）
に対し化学量論的に配合し、ボールミルにより、エタノ
ール中で２０時間混合した。これを８００℃で１時間保
持して仮焼し、次に、１０時間粉砕を行った。バインダ
ーとして、ポリビニルアルコールを用い、造粒し、圧力
１ｔｏｎ／ｃｍ²で直径２０ｍｍ、厚さ１ｍｍの円板状
に加圧成形した。焼成は、温度１１００℃で、２時間保
持して行った。EXAMPLES As raw materials, high purity Bi ₂ O ₃ and Na _{2 were used.}
CO ₃ , TiO ₂ and K ₂ CO ₃ were used. These are represented by the general formula [Bi _0.5 (Na _1-x K _x ) _0.5 ] TiO ₃ (0 <x <1)
Stoichiometrically, and mixed in a ball mill in ethanol for 20 hours. This was held at 800 ° C. for 1 hour and calcined, and then pulverized for 10 hours. Using polyvinyl alcohol as a binder, granulation was performed, and pressure molding was performed at a pressure of 1 ton / cm ² into a disc having a diameter of 20 mm and a thickness of 1 mm. The firing was performed at a temperature of 1100 ° C. for 2 hours.

【０００９】この焼結体の両面に銀電極を設け、１００
℃のシリコーンオイル中で直流電圧５ｋＶ／ｍｍを電極
間に加え、厚み方向に分極した。A silver electrode is provided on both sides of the sintered body,
A DC voltage of 5 kV / mm was applied between the electrodes in silicone oil at ° C. to polarize in the thickness direction.

【００１０】そして、これらの試料について、圧電、誘
電特性の測定を行った。圧電特性は、ＬＦインピーダン
スアナライザーを用い、共振−***振法により、電気機
械結合係数、機械的品質係数を算出した。また、誘電特
性は、ＬＣＲメーターを用いて測定周波数１ＭＨｚで測
定を行った。表１に［Ｂｉ_0.5（Ｎａ_1-xＫ_x）_0.5］Ｔｉ
Ｏ₃（０≦ｘ≦１）の電気機械結合係数ｋ₃₃，ｋｐ，ｋ
ｔ、機械的品質係数Ｑｍおよび比誘電率ε₃₃ ^t／ε₀値を
示す。[0010] The piezoelectric and dielectric properties of these samples were measured. For the piezoelectric characteristics, an electromechanical coupling coefficient and a mechanical quality coefficient were calculated by a resonance-antiresonance method using an LF impedance analyzer. The dielectric properties were measured at a measurement frequency of 1 MHz using an LCR meter. Table 1 shows that [Bi _0.5 (Na _1-x K _x ) _0.5 ] Ti
The electromechanical coupling coefficient k ₃₃ , kp, k of O ₃ (0 ≦ x ≦ 1)
t, the mechanical quality factor Qm and the relative permittivity ε ₃₃ ^t / ε ₀ are shown.

【００１１】[0011]

【表１】 [Table 1]

【００１２】表１より、Ｑｍ値は、２５０〜３００と、
一様に低い値をとることがわかる。From Table 1, the Qm values are from 250 to 300,
It can be seen that the value is uniformly low.

【００１３】そこで、［Ｂｉ_0.5（Ｎａ_0.9Ｋ_0.1）_0.5］
ＴｉＯ₃に対し、Ｍｎ₂Ｏ₃、Ｆｅ₂Ｏ ₃、ＮｉＯ、Ｃｏ₂Ｏ
₃、Ｃｒ₂Ｏ₃を、それぞれ１.０、２.０ｗｔ％添加し
た。表２に、電気機械結合係数ｋ₃₃、ｋｐ、ｋｔ、機械
的品質係数Ｑｍおよび比誘電率ε₃₃ ^t／ε₀の値を示す。Therefore, [Bi_0.5(Na_0.9K_0.1)_0.5]
TiO_ThreeWith Mn_TwoO_Three, Fe_TwoO _Three, NiO, Co_TwoO
_Three, Cr_TwoO_ThreeWere added at 1.0 and 2.0 wt%, respectively.
Was. Table 2 shows the electromechanical coupling coefficient k₃₃, Kp, kt, machine
Quality factor Qm and relative permittivity ε₃₃ ^t/ Ε₀Shows the value of

【００１４】[0014]

【表２】 [Table 2]

【００１５】表２において、Ｑｍの値は、添加物の種類
によらず、添加量の増加に伴い大きくなる。ＮｉＯを２
ｗｔ％加えた場合が、９０８と最も大きく、添加物なし
の場合と比較して、６５０程度の改善が確認できた。ま
た、電気機械結合係数は、若干の減少が確認できるもの
もあるが、どのモードでも添加物の種類、量の違いによ
る変化量は少なく、電気機械結合係数に対する添加物の
影響は少ないと考えられる。比誘電率は、添加量に対し
て減少する傾向が確認できる。また、添加量を２ｗｔ％
よりさらに増やしていくと、５ｋＶ、室温〜２００℃の
分極条件でも分極できず、工業生産を考慮した場合、実
用に適さないと判断できる。[0015] In Table 2, the value of Qm increases as the amount of addition increases, irrespective of the type of additive. NiO 2
The case of adding wt% was the largest at 908, and an improvement of about 650 was confirmed as compared with the case without the additive. In addition, although the electromechanical coupling coefficient may be slightly reduced, there is little change due to the type and amount of the additive in any mode, and the effect of the additive on the electromechanical coupling coefficient is considered to be small. . It can be confirmed that the relative permittivity tends to decrease with respect to the added amount. In addition, the addition amount is 2 wt%
If it is further increased, it cannot be polarized under the polarization conditions of 5 kV and room temperature to 200 ° C., and it can be determined that it is not suitable for practical use in consideration of industrial production.

【００１６】次に、［Ｂｉ_0.5（Ｎａ_0.4Ｋ_0.6）_0.5］Ｔ
ｉＯ₃に対し、Ｍｎ₂Ｏ₃、Ｆｅ₂Ｏ₃、ＮｉＯ、Ｃｏ
₂Ｏ₃、Ｃｒ₂Ｏ₃を、それぞれ１.０、２.０ｗｔ％添加し
た。表３に、電気機械結合係数ｋ₃₃，ｋｐ，ｋｔ、機械
的品質係数Ｑｍおよび比誘電率ε₃₃ ^t／ε₀の値を示す。Next, [Bi _0.5 (Na _0.4 K _0.6 ) _0.5 ] T
to _{_{_{iO 3, Mn 2 O 3,}}} Fe 2 O 3, NiO, Co
₂ O ₃ and Cr ₂ O ₃ were added at 1.0 and 2.0 wt%, respectively. Table 3 shows values of the electromechanical coupling coefficients k ₃₃ , kp, kt, the mechanical quality factor Qm, and the relative permittivity ε ₃₃ ^t / ε ₀ .

【００１７】[0017]

【表３】 [Table 3]

【００１８】表３において、電気機械結合係数は、添加
物の種類、量に大きな影響は受けていない。また、Ｑｍ
も添加物の量の増加に伴い、大きくなることが確認でき
た。最大値は、ＮｉＯを２ｗｔ％添加した場合で９２３
であり、ｘ＝０．１の場合と同様に６５０程度の改善が
確認できた。In Table 3, the electromechanical coupling coefficient is not significantly affected by the type and amount of the additive. Also, Qm
Was also increased with an increase in the amount of the additive. The maximum value is 923 when 2 wt% of NiO is added.
Approximately 650 improvement was confirmed as in the case of x = 0.1.

【００１９】なお、０＜ｘ＜１の他の組成域において
も、上記と同様の添加物の効果が確認できた。In the other composition range of 0 <x <1, the same effect of the additive as described above was confirmed.

【００２０】[0020]

【発明の効果】本発明によれば、無鉛で、高いＱｍを有
する圧電磁器組成物を提供することができ、高いＱｍが
望まれるフィルター、振動子等の用途への適用が可能と
なった。According to the present invention, it is possible to provide a piezoelectric ceramic composition which is lead-free and has a high Qm, and can be applied to applications such as a filter and a vibrator in which a high Qm is desired.

Claims

【特許請求の範囲】[Claims]

【請求項１】一般式［Ｂｉ_0.5（Ｎａ_1-xＫ_x）_0.5］Ｔ
ｉＯ₃（但し、０＜ｘ＜１）で表される圧電磁器組成物
において、Ｍｎ₂Ｏ₃、Ｃｏ₂Ｏ₃、Ｆｅ₂Ｏ₃、ＮｉＯ、Ｃ
ｒ₂Ｏ₃の少なくとも１種以上を２ｗｔ％以下含むことを
特徴とする圧電磁器組成物。1. The general formula [Bi _0.5 (Na _1-x K _x ) _0.5 ] T
In a piezoelectric ceramic composition represented by iO ₃ (where 0 <x <1), Mn ₂ O ₃ , Co ₂ O ₃ , Fe ₂ O ₃ , NiO, C
A piezoelectric ceramic composition comprising at least one kind of r ₂ O ₃ at 2 wt% or less.