JPH02229478A - Manufacture of composite piezoelectric body - Google Patents
Manufacture of composite piezoelectric bodyInfo
- Publication number
- JPH02229478A JPH02229478A JP1050466A JP5046689A JPH02229478A JP H02229478 A JPH02229478 A JP H02229478A JP 1050466 A JP1050466 A JP 1050466A JP 5046689 A JP5046689 A JP 5046689A JP H02229478 A JPH02229478 A JP H02229478A
- Authority
- JP
- Japan
- Prior art keywords
- piezoelectric material
- green sheet
- activated carbon
- composite piezoelectric
- carbon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002131 composite material Substances 0.000 title claims abstract description 54
- 238000004519 manufacturing process Methods 0.000 title claims description 20
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 114
- 239000000463 material Substances 0.000 claims abstract description 104
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 44
- 238000000034 method Methods 0.000 claims abstract description 44
- 239000007787 solid Substances 0.000 claims abstract description 28
- 238000010304 firing Methods 0.000 claims description 22
- 239000000126 substance Substances 0.000 claims description 6
- 238000010030 laminating Methods 0.000 claims description 3
- 238000003475 lamination Methods 0.000 claims 2
- 238000002485 combustion reaction Methods 0.000 abstract description 4
- 230000003647 oxidation Effects 0.000 abstract description 2
- 238000007254 oxidation reaction Methods 0.000 abstract description 2
- 230000006835 compression Effects 0.000 abstract 1
- 238000007906 compression Methods 0.000 abstract 1
- 239000002002 slurry Substances 0.000 description 21
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 7
- 239000011148 porous material Substances 0.000 description 7
- 230000005484 gravity Effects 0.000 description 6
- 239000000843 powder Substances 0.000 description 6
- 239000004698 Polyethylene Substances 0.000 description 5
- 239000000919 ceramic Substances 0.000 description 5
- -1 polyethylene Polymers 0.000 description 5
- 229920000573 polyethylene Polymers 0.000 description 5
- 230000035945 sensitivity Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- YEXPOXQUZXUXJW-UHFFFAOYSA-N oxolead Chemical compound [Pb]=O YEXPOXQUZXUXJW-UHFFFAOYSA-N 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000002518 antifoaming agent Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 239000003232 water-soluble binding agent Substances 0.000 description 1
Landscapes
- Laminated Bodies (AREA)
- Piezo-Electric Transducers For Audible Bands (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は、例えばハイドロホン等の送波器又は受波器
等に用いて好適な複合圧電体の製造方法に間するもので
、特に、圧電材料と、この圧電材料の誘電率とは異なる
誘電率を有する物質とから成る複合圧電体を製造する方
法に関するものである．
（従来の技術）
従来より、例えば音響センサの送受波器等の材料として
、種々の圧電体が使用ざれている．しかし、圧電体を用
いたセンサの感度の向上を図るためには、圧電特性の異
方性が大きい圧電体が必要である．そこで圧電特性の異
方性が大きい圧電体を得る方法が従来から研究ざれてい
た．その一例としては、有機材料（例えばエボキシ樹詣
、ウレタン樹脂等）中に圧電磁器粉末を混合させる方法
があった．また他の例としては、圧電磁器棒を所定間隔
で配列させこれら圧電磁器棒間に上述のような樹脂を充
填させる方法があった．しかしこれらの方法は、圧電磁
器粉末、圧電磁器棒等の圧電材料と、樹脂との密着性が
弱く、しばしば剥離等が生じ問題があった．
そこで、他の方法として、例えば、この出願人に係る特
願昭６２−２３９２３４に提案ざれている方法があった
．第４図（Ａ）及びＣＢ）はその方法の説明に供する製
造工程図である．この方法によれば、先ず、圧電材料よ
り成るグリーンシート１１上にカーボンバルーン１３を
散在させ積層単位１５が形成される（第４図（Ａ））．
次に、この積層単位１５ヲ必要枚数順次重ねた後この重
ねたものを加熱・加圧して圧電材料とカーボンバルーン
との積層体１７が形成される（第４図（Ｂ））．次に、
この積層体１７が焼成ざれる．この方法．によれば、上
記焼成の際にカーボンバルーン１３が酸化燃焼により消
失することを利用して焼成体中に空孔を形成出来るので
、空気／圧電材料系の複合圧電体が容易に得られた．
ざらに別の方法として、この出願に係る特願昭６３−３
２８７３に提案されている方法があった．この方法は、
ポリエチレン粒等のような高分子材料から成る粒と圧電
材料とを含有するグリーンシート、及び上記圧電材料の
みから成るグリーンシートを交互に積層して積層体を作
製し、次に、この積層体を焼成してこの焼成の際に高分
子材料粒が酸化燃焼により消失することを利用して焼成
体中に空孔を形成し、空気／圧電材料系の複合圧電体を
得るものであった．
（発明が解決しようとする課題）
しかしながら、上述した特願昭６２−２３９２３４に提
案されている複合圧電体の製造方法では、積層体１７を
形成する際に隣接積層単位１５同志の密着力を高めるた
めに加圧を行なうが、この際に中空であるカーボンバル
ーン１３のうちには破壊されるものが生じてしまう．こ
のため、予定した空孔率の焼成体が得られないという問
題点があった．さらに、カーボンバルーンの破壊の発生
度は一定しないので、空孔率が予定値からずれるのみな
らず、空孔率のバラツキは非常に大きくなるという問題
点があった．従って、得られた複合圧電体の特性は予定
のものとは異なったものとなったりバラツキの大きなも
のとなるので、この複合圧電体を用いたデバイスは満足
のゆくものではなくなってしまう．
また、特願昭６３−３２８７３に提案ざれている複合圧
電体の製造方法では、ポリエチレン等の高分子材料の比
重が、圧電材料のそれに比し大きく異なる（非常に小さ
い．通常１７５以下である）ため、ポリエチレン粒と、
圧電材料の粉末と、バインダーとを入念に混合しスラリ
ーを作製しても、均一な分散状態を示している時間は非
常に短い．このため、圧電゜材料と、高分子材料粒とを
均一に含有するグリーンシートが得にくいという問題点
があった．このため、得られた複合圧電体の特性バラツ
キは、大きくなってしまう．
この発明はこのような点に鑑みなされたものであり、従
ってこの発明の目的は、上述の問題点を解決し、圧電材
料と、該圧電材料の誘電率とは異なる誘電率を有する物
質との複合圧電体であぢて所望の特性を有する複合圧電
体を簡易に製造出来る方法を提供することにある．
（課題を解決するための手段）
この目的の達成を図るため、この発明の複合圧電体の製
造方法によれば、圧電材料と、この圧電材料の誘電率と
は異なる誘電率を有する物質との複合圧電体を製造する
（こ当り、
圧電材料及びこの圧電材料の焼成過程で消失する中実（
中空でないこと）カーボンを含有するグリーンシートを
形成する工程と、
前述のグリーンシートを焼成する工程とを含むことを特
徴とする．
なお、この発明の実施に当たっては、前述の圧電材料の
みから成るグリーンシートを形成し、このグリーンシー
トと、前述した圧電材料及び中実のカーボンを含有する
グリーンシートとを交互に積層し、これにより得た積層
体に対し前述の焼成を行ない複合圧電体を得るのが好適
である．または、前述した圧電材料及び中実のカーボン
を含有するグリーンシートを積層し、これにより得た積
層体に対し前述の焼成を行ない複合圧電体を得るのが好
適である．
（作用）
上述したこの発明の構成によれば、中実のカーボンが圧
電材料の焼成過程中に酸化焼成により消失した跡に空孔
が形成ざれる．従って、圧電材料と、空孔中の空気との
複合圧電体が形成出来る．或いは、空孔中に異種物質を
充填することも可能であるので、このようにした場合で
あれば、圧電材料と、この異種物質との複合圧電体が形
成される．
また、この発明の製造方法で用いる中実のカーボンは、
中空であるカーボンバルーンより破壊強度が高いので、
この中実のカーボンを含有するグリーンシートを積層し
で用いる場合に各グリーンシート間の密着力を上ザるた
め加圧を行なっても、破壊されにくい．
さらに、この中実のカーボンの比重は、ポリエチレン等
の高分子材料のそれより圧電材料の比重により近いので
、圧電材料及び中実のカーボンが、スラリー中で均一に
分散するようになる．また、圧電材料のみから成るグリ
ーンシートと、該圧電材料及び該圧電材料の焼成過程で
消失する中実のカーボンを含有するグリーンシートとを
交互に積層した積層体を焼成して得た複合圧電体によれ
ば、積層方向とこれに直交する方向の構造が大きく異な
るので、圧電特性の異方性がより大きくなる．
（実施例）
以下、図面を参照してこの発明の複合圧電体の製造方法
の実施例につき説明する．なお、説明に用いる第１及び
第２図は、この発明を理解出来る程度に概略的に示して
あるにすぎず、従って、各構成成分の形状、寸法、ざら
に各構成成分間の寸法比は概略的であり、この発明が図
示例に限定ざれるものではないことは理解されたい．ま
た、第１図及び第２図において同様な構成成分について
は、同一の符号を付して示してある．また、以下の実施
例は、圧電材料をチタン酸ジルコン酸鉛［ Ｐｂ（Ｚｒ
−Ｔｉ）Ｏｓ ：以下ＰＺＴと称する．］とし、このＰ
ＺＴの誘電率とは異なる誘電率を有する物質を空気とし
た例で説明する．
袈】」』１久脱朋
以下のような手順で複合圧電体を製造した．先ず、圧電
材料としてのＰＺＴと、このＰＺＴの焼成過程で消失す
る中実のカーボンとを含有するグリーンシートを以下に
説明するように形成した．
化学的にそれぞれ高純度な、ｐｂ○（一酸化鉛）、Ｔｉ
Ｏ２ （二酸化チタン）、ｚｒｏ２ （二酸化ジルコニ
ウム）及びその他の添加剤をそれぞれ所定量秤量し、こ
れらをボットミルを用いて純水と共に約２０時間混合す
る．その後、この混合物を脱水乾燥し、その後、９００
〜１０００℃の温度で２時間焼成し仮焼物を得た．その
後、再びボットミルを用い純水と共にこの仮焼物を粉砕
し、その後、粉砕物を脱水乾燥して、ＰＺＴの仮焼粉を
得た．
次に、このＰＺＴの仮焼粉に、水溶性バインダ、分散剤
、可塑剤及び消泡剤を添加し、さらに圧電材料の焼成過
程で消失する中実のカーボンとして、この実施例の場合
、呉羽化学（株）製の活性炭で直径が約０．３ｍｍの球
状活性炭を添加した．そして、ボットミルにて充分に混
合し圧電材料と、中実のカーボンとを含有するスラリ−
（以下、活性炭入りスラリーと称する．）ヲ作製した．
次に、この活性炭入りスラリーを用いドクターブレード
装置により、ＰＺＴと球状活性炭とを含有する厚さが０
．５〜１ ｍｍのグリーンシート（以下、活性炭入りグ
リーンシートと称する．）を作製した．
一方、活性炭を添加しないこと以外は活性炭入りスラリ
ーを作製した工程と同様な工程により、圧電材料のみか
ら成るスラリ−（以下、活性炭無しスラリーと称する．
）を作製した．そして、この活性炭無しスラリーを用い
ドクターブレード装宜により、厚さ力司．５〜１ ｍｍ
のＰＺＴのみのグリーンシート（以下、活性炭無しグリ
ーンシートと称する，）を作製した．
次に、第１図に断面図を以って示すように、活性炭入り
グリーンシート２１と、活性炭無しグリーンシート２３
とを交互に必要枚数積層し、その後、これを１００℃の
温度下で１５０〜２００κｇ／ｃｍ２の圧力で加圧し各
グリーンシート同志を圧着させて、積層体２５（以下、
実施例１の積層体２５と称する）を作製した．
また、第２図に断面図を以って示すように、活性炭入り
グリーンシート２１のみを必要枚数積層し実施例１の積
層体２５作製時と同様な加熱・加圧条件で積層体２７（
以下、実施例２の積層体２７と称する）を作製した．
なお、第１図及び第２図１こおいで、２１ａは中実のカ
ーボンである活性炭である．
次に、実施例］の積層体２５及び実施例２の積層体２７
を、空気中にで１２００〜＋３００’Ｃの温度で２時間
焼成した．この焼成において、活性炭は、酸化燃焼によ
り消失しでしまいその跡は空孔となった．この結果、空
気／ＰＺＴ系の複合圧電体が得られた．
上述したような製造方法に従い、実施例１の構造の複合
圧電体については、ＰＺＴ仮焼粉に対する活性炭の含有
比を変えたスラリーをそれぞれ作製し、空孔率が４２％
、４５％の２ｆ！類の複合圧電体を作製した．また、実
施例２の構造の複合圧電体については、空孔率が５０％
のもの１種類を作製した．
合電の の
次に、上述の如く製造した空孔率が異なる各複合圧電体
の圧電特性を以下に説明するような手順で測定した．
先ず、各複合圧電体ｔ５Ｘ５Ｘ２４ｍｍの柱形状に加工
した．なお、柱形状物の２４ｍｍの寸法となっている方
向は、第１図及びＭ２図ｆこｌで示した方向である．
次に、５×２４の長方形の面のうちの対向する２面に銀
を焼付けて電極とした．
次に、この試料！１２０’Ｃの温度のシリコーンオイル
中に浸潰しこの試料に対し２．５κＶ／ｍｍの電界を加
えて分極を行なった．
次に、分極の終了した試料の電極の端部にリード線をは
んだ付けした後この試料の５ｘ２４ｍｍの各面をウレタ
ンモールドし直径１０ｍｍの円筒形状のハイドロホンを
作製した．
このようにして作製した実施例の複合圧電体を用いたハ
イド口ホンの受波感度を以下に説明するように測定した
．
ハイドロホンは水槽中の水深０．７ｍの位置でかつ送波
器から０．５ｍｊｌ間した位置に１いた．送波器から出
力される信号の周波数を４０〜２００ＫＨｚの範囲で変
化させ、ハイドロホンに発生した電圧を読取った．
第３図は、この測定結果を示したもので、横軸に送波器
の出力信号の周波数（κ｝ｌｚ）をとり、縦軸にハイド
口ホンの受波感度（ｄＢ／／Ｖ／μＰａ） ？とり示し
たものである．第２図中、●印で示した特性曲線は、活
性炭入りグリーンシートを積層した積層体を焼成して得
た複合圧電体であって空孔率が５０％の複合圧電体を用
いたハイドロホンの特性である．また、▲印で示した特
性曲線は、活性炭入り及び活性炭無しの各グリーンシー
トを交互に積層した積層体を焼成しで得た複合圧電体で
あって空孔率が４５％の複合圧電体を用いたハイド口ホ
ンの特性である．また、Δ印で示した特性曲線は、活性
炭入り及び活性炭無しの各グリーンシートを交互に積層
した積層体を焼成して得た複合圧電体であって空孔率が
４２％の複合圧電体を用いたハイドロホンの特性である
．また、第３図に○印で示した特性曲線は、比較例のも
のであり、空孔率が０％の複合圧電体を用いたハイドロ
ホン、即ち活性炭無しグリーンシートのみを必要枚数積
層し実施例同様な加熱、加圧、焼成及び加工を施して作
製した比較例のハイドロホンの受波特性である．
第３図からも理解できるように、空孔を有する空気／Ｐ
ＺＴ系の実施例の複合圧電体を用いたハイドロホンは、
比較例に比し、受波感度が７〜１２ｄＢも向上すること
が分る．
ウ る。Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method of manufacturing a composite piezoelectric material suitable for use in a wave transmitter or receiver of a hydrophone, etc. This invention relates to a method for manufacturing a composite piezoelectric body consisting of a piezoelectric material and a substance having a dielectric constant different from that of the piezoelectric material. (Prior Art) Various piezoelectric materials have been used as materials for, for example, transducers of acoustic sensors. However, in order to improve the sensitivity of sensors using piezoelectric materials, piezoelectric materials with large anisotropy of piezoelectric properties are required. Therefore, methods to obtain piezoelectric materials with large anisotropy of piezoelectric properties have been studied for a long time. One example is a method in which piezoelectric ceramic powder is mixed into an organic material (e.g., epoxy resin, urethane resin, etc.). Another example is a method in which piezoelectric ceramic rods are arranged at predetermined intervals and the spaces between these piezoelectric ceramic rods are filled with resin as described above. However, these methods have had problems in that the adhesion between the piezoelectric materials such as piezoelectric ceramic powders and piezoelectric ceramic rods and the resin is weak, and peeling often occurs. Therefore, as another method, for example, there is a method proposed in Japanese Patent Application No. 62-239234 filed by this applicant. Figures 4(A) and CB) are manufacturing process diagrams for explaining the method. According to this method, first, carbon balloons 13 are scattered on a green sheet 11 made of a piezoelectric material to form a laminated unit 15 (FIG. 4(A)).
Next, the required number of laminated units 15 are stacked one on top of the other, and the stacked pieces are heated and pressurized to form a stacked body 17 of the piezoelectric material and the carbon balloon (FIG. 4(B)). next,
This laminate 17 is fired. This method. According to the above method, voids can be formed in the fired body by utilizing the fact that the carbon balloon 13 disappears due to oxidative combustion during the firing, so that an air/piezoelectric material-based composite piezoelectric body can be easily obtained. As a completely different method, the patent application related to this application
There was a method proposed in 2873. This method is
A laminate is produced by alternately laminating green sheets containing particles made of a polymeric material such as polyethylene particles and a piezoelectric material, and green sheets made only of the piezoelectric material, and then this laminate is The method was to create a composite piezoelectric material based on air/piezoelectric material by creating pores in the fired material by taking advantage of the fact that the polymeric material particles disappear due to oxidative combustion during firing. (Problem to be Solved by the Invention) However, in the method for manufacturing a composite piezoelectric body proposed in the above-mentioned Japanese Patent Application No. 62-239234, when forming the laminate 17, the adhesion between adjacent laminate units 15 is increased. For this purpose, pressurization is applied, but at this time some of the hollow carbon balloons 13 are destroyed. For this reason, there was a problem in that a fired body with the expected porosity could not be obtained. Furthermore, since the degree of fracture in the carbon balloon is not constant, there is a problem in that not only does the porosity deviate from the expected value, but the variation in porosity becomes extremely large. Therefore, the properties of the obtained composite piezoelectric material may be different from those expected or have large variations, so that devices using this composite piezoelectric material are no longer satisfactory. In addition, in the method for manufacturing a composite piezoelectric body proposed in Japanese Patent Application No. 63-32873, the specific gravity of the polymeric material such as polyethylene is significantly different from that of the piezoelectric material (very small, usually 175 or less). Therefore, polyethylene grains and
Even if a slurry is made by carefully mixing piezoelectric material powder and a binder, the time it takes for the slurry to remain uniformly dispersed is very short. For this reason, there was a problem in that it was difficult to obtain a green sheet that uniformly contained piezoelectric material and polymeric material particles. For this reason, the variations in properties of the obtained composite piezoelectric material become large. The present invention has been made in view of these points, and therefore, an object of the present invention is to solve the above-mentioned problems and to provide a method for combining a piezoelectric material and a substance having a dielectric constant different from that of the piezoelectric material. The object of this invention is to provide a method for easily manufacturing a composite piezoelectric material having desired characteristics. (Means for Solving the Problem) In order to achieve this object, according to the method for manufacturing a composite piezoelectric material of the present invention, a piezoelectric material and a substance having a dielectric constant different from that of the piezoelectric material are combined. Manufacture a composite piezoelectric material.
The method is characterized by comprising a step of forming a green sheet containing carbon (not hollow) and a step of firing the green sheet as described above. In carrying out the present invention, a green sheet made only of the piezoelectric material described above is formed, and this green sheet and a green sheet containing the piezoelectric material and solid carbon described above are alternately laminated. It is preferable to perform the above-mentioned firing on the obtained laminate to obtain a composite piezoelectric material. Alternatively, it is preferable to laminate the piezoelectric material described above and green sheets containing solid carbon, and then perform the sintering described above on the resulting laminate to obtain a composite piezoelectric body. (Function) According to the configuration of the present invention described above, pores are formed at the sites where solid carbon disappears due to oxidation firing during the firing process of the piezoelectric material. Therefore, a composite piezoelectric body can be formed from the piezoelectric material and the air in the pores. Alternatively, it is also possible to fill the pores with a different kind of material, so in this case, a composite piezoelectric body of the piezoelectric material and this different kind of material is formed. Moreover, the solid carbon used in the manufacturing method of this invention is
It has higher breaking strength than hollow carbon balloons, so
When these solid carbon-containing green sheets are used in a stacked manner, they will not easily break even if pressure is applied to increase the adhesion between each green sheet. Furthermore, the specific gravity of this solid carbon is closer to that of the piezoelectric material than that of a polymeric material such as polyethylene, so that the piezoelectric material and solid carbon are uniformly dispersed in the slurry. In addition, a composite piezoelectric material obtained by firing a laminate in which green sheets made only of piezoelectric material and green sheets containing the piezoelectric material and solid carbon that disappears during the firing process of the piezoelectric material are alternately laminated. According to , since the structure in the stacking direction and the direction perpendicular to this are significantly different, the anisotropy of the piezoelectric properties becomes larger. (Example) Hereinafter, an example of the method for manufacturing a composite piezoelectric body of the present invention will be described with reference to the drawings. Note that FIGS. 1 and 2 used for explanation are merely shown schematically to the extent that this invention can be understood, and therefore, the shapes, dimensions, and rough size ratios of each component are It is to be understood that this is a schematic representation and that the invention is not limited to the illustrated example. In addition, similar components in FIGS. 1 and 2 are designated by the same reference numerals. In addition, in the following examples, the piezoelectric material is made of lead zirconate titanate [Pb(Zr
-Ti)Os: Hereinafter referred to as PZT. ], and this P
This will be explained using an example in which air is a substance with a dielectric constant different from that of ZT. A composite piezoelectric material was manufactured using the following procedure. First, a green sheet containing PZT as a piezoelectric material and solid carbon that disappears during the firing process of this PZT was formed as described below. Chemically highly pure pb○ (lead monoxide) and Ti
Weigh out predetermined amounts of O2 (titanium dioxide), ZRO2 (zirconium dioxide), and other additives, and mix them with pure water using a bot mill for about 20 hours. This mixture was then dehydrated and dried at 900 °C.
A calcined product was obtained by firing at a temperature of ~1000°C for 2 hours. Thereafter, this calcined product was again pulverized with pure water using a bot mill, and then the pulverized product was dehydrated and dried to obtain a PZT calcined powder. Next, a water-soluble binder, a dispersant, a plasticizer, and an antifoaming agent are added to this calcined powder of PZT, and in the case of this example, Kureha is added as solid carbon that disappears during the firing process of the piezoelectric material. Spherical activated carbon made by Kagaku Co., Ltd. and having a diameter of approximately 0.3 mm was added. Then, the slurry containing the piezoelectric material and solid carbon is thoroughly mixed in a bot mill.
(hereinafter referred to as activated carbon-containing slurry) was prepared. Next, using this activated carbon-containing slurry, a doctor blade device is used to prepare a slurry containing PZT and spherical activated carbon with a thickness of 0.
．． A green sheet (hereinafter referred to as activated carbon-containing green sheet) with a thickness of 5 to 1 mm was prepared. On the other hand, a slurry consisting only of piezoelectric material (hereinafter referred to as slurry without activated carbon) was prepared using the same process as the one used to prepare the slurry containing activated carbon, except that activated carbon was not added.
) was created. Then, using this activated carbon-free slurry and using a doctor blade, the thickness of the slurry was determined. 5-1mm
A green sheet containing only PZT (hereinafter referred to as a green sheet without activated carbon) was prepared. Next, as shown in FIG. 1 with a sectional view, a green sheet 21 containing activated carbon and a green sheet 23 without activated carbon are prepared.
The required number of green sheets are laminated alternately, and then this is pressurized at a pressure of 150 to 200 κg/cm2 at a temperature of 100°C to bond each green sheet to each other to form a laminate 25 (hereinafter referred to as
A laminate (referred to as laminate 25 of Example 1) was produced. Further, as shown in FIG. 2 with a cross-sectional view, a required number of activated carbon-containing green sheets 21 were laminated and a laminate 27 (
A laminate (hereinafter referred to as laminate 27 of Example 2) was produced. In addition, in FIGS. 1 and 2, 21a is activated carbon, which is solid carbon. Next, the laminate 25 of Example] and the laminate 27 of Example 2
was calcined in air at a temperature of 1200 to +300'C for 2 hours. During this firing, the activated carbon disappeared due to oxidative combustion, leaving behind voids. As a result, an air/PZT-based composite piezoelectric material was obtained. According to the manufacturing method described above, slurries with different content ratios of activated carbon to PZT calcined powder were prepared for composite piezoelectric bodies having the structure of Example 1, and the porosity was 42%.
, 45% 2f! We fabricated similar composite piezoelectric materials. Furthermore, for the composite piezoelectric material having the structure of Example 2, the porosity was 50%.
I made one type of this. After combining, the piezoelectric properties of each of the composite piezoelectric materials with different porosity manufactured as described above were measured using the procedure described below. First, each composite piezoelectric material was processed into a pillar shape of t5 x 5 x 24 mm. Note that the direction in which the column-shaped object has a dimension of 24 mm is the direction shown in Fig. 1 and Fig. M2. Next, silver was baked on two opposing sides of the 5x24 rectangle to form electrodes. Next, this sample! The sample was immersed in silicone oil at a temperature of 120'C and polarized by applying an electric field of 2.5κV/mm to the sample. Next, after soldering lead wires to the ends of the electrodes of the polarized sample, each 5 x 24 mm surface of this sample was molded with urethane to produce a cylindrical hydrophone with a diameter of 10 mm. The wave reception sensitivity of the Hyde mouthphone using the composite piezoelectric material of the example thus prepared was measured as explained below. The hydrophone was located in the water tank at a depth of 0.7 m and 0.5 mjl from the transmitter. The frequency of the signal output from the transmitter was varied in the range of 40 to 200 KHz, and the voltage generated at the hydrophone was read. Figure 3 shows the measurement results, where the horizontal axis represents the frequency (κ}lz) of the output signal of the transmitter, and the vertical axis represents the receiving sensitivity of the Hyde mouthpiece (dB//V/μPa). )? This is what I have shown. In Figure 2, the characteristic curve marked with ● indicates a hydrophone using a composite piezoelectric material with a porosity of 50%, which is obtained by firing a laminate of activated carbon-containing green sheets. This is the characteristic of In addition, the characteristic curve indicated by ▲ is a composite piezoelectric material with a porosity of 45%, which is obtained by firing a laminate in which green sheets with activated carbon and without activated carbon are laminated alternately. These are the characteristics of the Hyde mouthphone used. In addition, the characteristic curve indicated by Δ is a composite piezoelectric material with a porosity of 42%, which is obtained by firing a laminate in which green sheets with and without activated carbon are laminated alternately. These are the characteristics of the hydrophone used. In addition, the characteristic curve marked with a circle in Fig. 3 is that of a comparative example, which is a hydrophone using a composite piezoelectric material with a porosity of 0%, in other words, the required number of green sheets without activated carbon were laminated. This is the wave reception characteristics of a hydrophone of a comparative example, which was manufactured using the same heating, pressurizing, firing, and processing methods as in the example. As can be understood from Fig. 3, air with pores/P
A hydrophone using a ZT-based composite piezoelectric material is as follows:
It can be seen that the reception sensitivity is improved by 7 to 12 dB compared to the comparative example. Uru.
次に、複合圧電体作製のためのスラリーが、圧電材料と
中実のカーボン（活性炭）とを含有するスラリーの場合
（実施例）、また、圧電材料と中空のカーボン（カーボ
ンバルーン）とを含有するスラリーの場合それぞれにお
いて、活性炭或いはカーボンバルーンを空孔率が５０％
となるように想定して含有した場合の、得られた複合圧
電体の空孔率の再現性につきそれぞれ調査した．なお、
カーボンバルーンは、「クレカスフェア」 （呉羽化学
（株）製）を用いた．また、比較例のスラリーは、実施
例の複合圧電体を作製するためのスラリーを作製する工
程と同様な工程に従い作製した．なお、比較例にお（ナ
る積層グリーンシートを加圧する圧力は、実施例の約１
７３の５０〜６０κｑ／ｃｍ２とした．また、出来上っ
た実施例及び比較例の複合圧電体の空孔率は、試料の体
積と重さとから見かけの比重を求め、この見かけの比重
と、ＰＺＴの比重（この実施例の場合は７．５である．
）との差から計算により求めた．
第１表に、実施例及び比較例それぞれのスラリーから複
数個づつ作製した各複合圧電体の空孔率の、平均値及び
バラツキを示した。この結果からも明らかなように、中
実のカーボンはカーボンバルーンに比し加圧によっても
破壊されにくいため、これを用いている複合圧電体のほ
うが、所望の空孔率に近い空孔率を示し然もバラツキも
小ざ第１表
以上がこの発明の実施例であるが、この発明は上述の実
施例にのみ限定ざれるものではない．例えば中寅のカー
ボンの形状は球状以外の形状でも勿論良い．ざらに、活
性炭以外の他の好適なものを中実のカーボンとして用い
ても良い．また、この発明を適用出来る圧電材料は、Ｐ
ＺＴに限られるものではなく他のものでも良い．また、
上述の実施例では、活性炭入りグリーンシートと、活性
炭無しグリーンシートとを交互に１枚づつ積層する場合
、活性炭入りグリーンシートのみを多数積層する場合の
２例につき説明している．しかし、活性炭入りグリーン
シートと、活性炭無しグリーンシートとを用いる場合、
１枚づつ交互に積層するのではなく、設計によっては複
数枚づつ交互に、或いは互いに異なる枚数づつ交互に積
層するようにしても良い．
（発明の効果）
上述した説明からも明らかなように、この発明の複合圧
電体の製造方法によれば、圧電材料と、該圧電材料の焼
成過程で消失する中実のカーボンとを含有するグリーン
シートを作製し、これを焼成し、この焼成中に中芙カー
ポ゛ンを消失ざせて、空孔を有する圧電体を形成する。Next, if the slurry for producing a composite piezoelectric body is a slurry containing a piezoelectric material and solid carbon (activated carbon) (example), or a slurry containing a piezoelectric material and hollow carbon (carbon balloon), In each case, activated carbon or carbon balloons with a porosity of 50% are used.
We investigated the reproducibility of the porosity of the obtained composite piezoelectric material when the content was assumed to be as follows. In addition,
The carbon balloon used was ``Creka Sphere'' (manufactured by Kureha Chemical Co., Ltd.). In addition, the slurry of the comparative example was produced according to the same process as the process of producing the slurry for producing the composite piezoelectric body of the example. In addition, in the comparative example, the pressure applied to the laminated green sheet was approximately 1
73 and 50 to 60 κq/cm2. In addition, the porosity of the composite piezoelectric materials of the completed examples and comparative examples is determined by calculating the apparent specific gravity from the volume and weight of the sample, and then calculating the apparent specific gravity and the specific gravity of PZT (in the case of this example, It is 7.5.
) was calculated from the difference between Table 1 shows the average value and dispersion of the porosity of each composite piezoelectric material produced from the slurry of each example and comparative example. As is clear from this result, solid carbon is less likely to be destroyed by pressure than a carbon balloon, so composite piezoelectric materials using this material have a porosity closer to the desired porosity. Table 1 and above are examples of the present invention, but the present invention is not limited to the above-mentioned examples. For example, the shape of Nakatora's carbon may of course be other than spherical. Alternatively, other suitable materials other than activated carbon may be used as the solid carbon. Furthermore, the piezoelectric material to which this invention can be applied is P
It is not limited to ZT and may be other types. Also,
In the above-mentioned embodiments, two cases are explained: a case where green sheets containing activated carbon and a green sheet without activated carbon are laminated one by one alternately, and a case where a large number of green sheets containing only activated carbon are laminated. However, when using green sheets with activated carbon and green sheets without activated carbon,
Instead of laminating one sheet at a time, depending on the design, a plurality of sheets or a different number of sheets may be alternately laminated. (Effects of the Invention) As is clear from the above explanation, according to the method for manufacturing a composite piezoelectric material of the present invention, a green material containing a piezoelectric material and solid carbon that disappears during the firing process of the piezoelectric material is produced. A sheet is produced and fired, and during the firing, the hollow carbon disappears to form a piezoelectric body having holes.
従って、空孔を利用した圧電特性の異方性が大きい複合
圧電体を得ることが出来る．．
ここで、中実のカーボンは、中空であるカーボンバルー
ンより破壊強度が高いので、この中実のカーボンを含有
するグリーンシートを積層して用いる場合に各グリーン
シート間の密着力を上げるため加圧を行なっても、破壊
ざれにくい。このため、所望の空孔率を有する複合圧電
体を容易に得ることが出来る．ざらに、カーボンバルー
ンを用いる場合より大きな力で加圧を行なうことが出来
るので、グリーンシート間の密着性が高まり、焼成体に
ワレ、クラックが生じにくくなる．ざらに、中実のカー
ボンの比重は、ポリエチレン等の高分子材料のそれより
圧電材料の比重により近いので、スラリー作製後これを
長時間保存しておいても圧電材料及び中英のカーボンが
分離しづらい．このため、このスラリーから得られるグ
リーンシートは、中実カーボンが均一に分散したものと
なるので、この結果、空孔が均一に分布している複合圧
電体が得られる．
これがため、圧電材料と、該圧電材料の誘電率とは異な
る誘電率を有する物質（特に空気）との複合圧電体であ
って所望の特性を有する複合圧電体を簡易に製造出来、
この結果、感度が高く特性バラッキの少ないハイドロホ
ン等の作製も可能になる．Therefore, it is possible to obtain a composite piezoelectric material with large anisotropy of piezoelectric properties using pores. ．． Here, solid carbon has higher breaking strength than a hollow carbon balloon, so when using green sheets containing this solid carbon in layers, pressure is applied to increase the adhesion between each green sheet. Even if you do this, it will not be easily destroyed. Therefore, a composite piezoelectric material having a desired porosity can be easily obtained. In general, since it is possible to apply pressure with a greater force than when using a carbon balloon, the adhesion between the green sheets increases, making it difficult for cracks to occur in the fired product. Roughly speaking, the specific gravity of solid carbon is closer to that of piezoelectric material than that of polymeric materials such as polyethylene, so even if the slurry is stored for a long time after it is made, the piezoelectric material and solid carbon will not separate. difficult. Therefore, the green sheet obtained from this slurry has solid carbon uniformly dispersed therein, and as a result, a composite piezoelectric material in which pores are uniformly distributed can be obtained. Therefore, it is possible to easily produce a composite piezoelectric material having desired characteristics, which is a composite piezoelectric material made of a piezoelectric material and a substance (especially air) having a dielectric constant different from that of the piezoelectric material.
As a result, it becomes possible to create hydrophones with high sensitivity and little variation in characteristics.
第１図及び第２図は、実施例の説明に供する図、
第３図は、この発明に係る複合圧電体を用いて作製した
ハイドロホンの受波特性を示す図、第４図（Ａ）及び（
Ｂ）は、従来の製造方法の説明に供する工程図である．
２ １−・・活性炭入りグリーンシート２１ａ・一中実
のカーボン（球状活性炭）２３・・・活性炭無しグリー
ンシートFIGS. 1 and 2 are diagrams for explaining examples, FIG. 3 is a diagram showing the reception characteristics of a hydrophone manufactured using the composite piezoelectric material according to the present invention, and FIG. 4 (A )as well as(
B) is a process diagram for explaining the conventional manufacturing method. 2 1- Green sheet with activated carbon 21a Solid carbon (spherical activated carbon) 23 Green sheet without activated carbon
Claims (3)
率を有する物質との複合圧電体を製造するに当り、 圧電材料及び該圧電材料の焼成過程で消失する中実のカ
ーボンを含有するグリーンシートを形成する工程と、 前記グリーンシートを焼成する工程と を含むことを特徴とする複合圧電体の製造方法。(1) When manufacturing a composite piezoelectric body of a piezoelectric material and a substance having a dielectric constant different from that of the piezoelectric material, the piezoelectric material contains solid carbon that disappears during the firing process of the piezoelectric material. 1. A method for manufacturing a composite piezoelectric material, the method comprising: forming a green sheet, and firing the green sheet.
、 前記圧電材料のみから成るグリーンシートを形成し、 該グリーンシートと、前記圧電材料及び中実のカーボン
を含有するグリーンシートとを交互に積層し、 該積層により得た積層体に対し前記焼成を行なうこと を特徴とする複合圧電体の製造方法。(2) The method for manufacturing a composite piezoelectric body according to claim 1, further comprising forming a green sheet made only of the piezoelectric material, and alternating the green sheet with a green sheet containing the piezoelectric material and solid carbon. A method for manufacturing a composite piezoelectric material, comprising: laminating the composite piezoelectric material, and performing the firing on the laminate obtained by the lamination.
、 前記圧電材料及び中実のカーボンを含有するグリーンシ
ートを積層し、該積層により得た積層体に対し前記焼成
を行なうこと を特徴とする複合圧電体の製造方法。(3) The method for manufacturing a composite piezoelectric body according to claim 1, characterized in that green sheets containing the piezoelectric material and solid carbon are laminated, and the laminate obtained by the lamination is subjected to the firing. A method for manufacturing a composite piezoelectric material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1050466A JPH02229478A (en) | 1989-03-02 | 1989-03-02 | Manufacture of composite piezoelectric body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1050466A JPH02229478A (en) | 1989-03-02 | 1989-03-02 | Manufacture of composite piezoelectric body |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02229478A true JPH02229478A (en) | 1990-09-12 |
Family
ID=12859658
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1050466A Pending JPH02229478A (en) | 1989-03-02 | 1989-03-02 | Manufacture of composite piezoelectric body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02229478A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013501490A (en) * | 2009-08-07 | 2013-01-10 | バイヤー・マテリアルサイエンス・アーゲー | Method for manufacturing an electromechanical transducer |
-
1989
- 1989-03-02 JP JP1050466A patent/JPH02229478A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013501490A (en) * | 2009-08-07 | 2013-01-10 | バイヤー・マテリアルサイエンス・アーゲー | Method for manufacturing an electromechanical transducer |
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