JPS62172776A - Manufacture of piezoelectric ceramics - Google Patents
Manufacture of piezoelectric ceramicsInfo
- Publication number
- JPS62172776A JPS62172776A JP61014314A JP1431486A JPS62172776A JP S62172776 A JPS62172776 A JP S62172776A JP 61014314 A JP61014314 A JP 61014314A JP 1431486 A JP1431486 A JP 1431486A JP S62172776 A JPS62172776 A JP S62172776A
- Authority
- JP
- Japan
- Prior art keywords
- axis
- piezoelectric ceramics
- electric field
- polarization
- molded body
- 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
- 239000000919 ceramic Substances 0.000 title claims abstract description 66
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 239000000843 powder Substances 0.000 claims abstract description 33
- 230000010287 polarization Effects 0.000 claims abstract description 22
- 230000005684 electric field Effects 0.000 claims abstract description 21
- 238000010304 firing Methods 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000010419 fine particle Substances 0.000 claims description 5
- 229910002113 barium titanate Inorganic materials 0.000 abstract description 10
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 abstract description 10
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 abstract description 6
- 229910052751 metal Inorganic materials 0.000 abstract description 4
- 239000002184 metal Substances 0.000 abstract description 4
- 239000000395 magnesium oxide Substances 0.000 abstract description 3
- 230000000717 retained effect Effects 0.000 abstract 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 8
- 239000013078 crystal Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 229910052697 platinum Inorganic materials 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000000465 moulding Methods 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 230000008569 process Effects 0.000 description 3
- 238000010298 pulverizing process Methods 0.000 description 3
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000007606 doctor blade method Methods 0.000 description 2
- 230000028161 membrane depolarization Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 241000219146 Gossypium Species 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical group ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- RQPZNWPYLFFXCP-UHFFFAOYSA-L barium dihydroxide Chemical compound [OH-].[OH-].[Ba+2] RQPZNWPYLFFXCP-UHFFFAOYSA-L 0.000 description 1
- 229910001863 barium hydroxide Inorganic materials 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- NJLLQSBAHIKGKF-UHFFFAOYSA-N dipotassium dioxido(oxo)titanium Chemical compound [K+].[K+].[O-][Ti]([O-])=O NJLLQSBAHIKGKF-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052451 lead zirconate titanate Inorganic materials 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
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- QXYJCZRRLLQGCR-UHFFFAOYSA-N molybdenum(IV) oxide Inorganic materials O=[Mo]=O QXYJCZRRLLQGCR-UHFFFAOYSA-N 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- -1 phthalate ester Chemical class 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 230000008685 targeting Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
Abstract
Description
【発明の詳細な説明】
〔技術分野〕
この発明は、圧電セラミックスの製法に関する〔背景技
術〕
近年、非常な勢いで電子機器のコンパクト化が進んでい
るが、そのため、機器に使われる電子部品も、小型・軽
量化が強く要求されている。そのような電子部品の材料
のひとつに圧電セラミックスがある。この圧電セラミッ
クスは、センサーやろ波器、圧電振動子、圧電トランス
、マイクロフォン、ピックアップ、圧電バイモルフ、圧
電ユニモルフ、アクチュエータなど、多岐にわたって活
用されている。[Detailed Description of the Invention] [Technical Field] The present invention relates to a method for manufacturing piezoelectric ceramics [Background Art] In recent years, electronic devices have become more compact at a rapid pace, and as a result, electronic components used in the devices have also become more compact. There is a strong demand for smaller size and lighter weight. Piezoelectric ceramics are one of the materials for such electronic components. This piezoelectric ceramic is used in a wide variety of applications, including sensors, filters, piezoelectric vibrators, piezoelectric transformers, microphones, pickups, piezoelectric bimorphs, piezoelectric unimorphs, and actuators.
圧電セラミックスの代表的なものとして、チタン酸バリ
ウム（ＢａＴｉＯ：＋）やチタン酸ジルコン酸鉛（Ｐｂ
Ｔｉｘ Ｚｒ＋−ｘ ０３）がある。これらの結晶はペ
ロプスカイト構造を有している。通常は、これらのもの
に他のペロブスカイト構造を有する材料を配合した多成
分系の圧電セラミックスが市販されている。Typical piezoelectric ceramics include barium titanate (BaTiO:+) and lead zirconate titanate (Pb
Tix Zr+-x 03). These crystals have a perovskite structure. Usually, multi-component piezoelectric ceramics made by blending these materials with other materials having a perovskite structure are commercially available.
圧電セラミックスを用いた電子部品の小型・軽量化を実
現するには、圧電セラミックスの高性能化をはからなけ
ればならない。上記の市販の圧電セラミックスなどに用
いられるセラミックス材の自発分極は、通常、等方性で
ある。そのため、このセラミックス材に高電圧をかけ、
自発分極の向きを特定方向に揃える（異方性をもたせる
）分極処理（ｐｏｌｉｎｇ）をおこなって圧電機能をも
たせるようにしている。In order to make electronic components using piezoelectric ceramics smaller and lighter, it is necessary to improve the performance of piezoelectric ceramics. The spontaneous polarization of the ceramic materials used in the commercially available piezoelectric ceramics and the like described above is usually isotropic. Therefore, by applying high voltage to this ceramic material,
A piezoelectric function is provided by performing polarization processing (poling) to align the direction of spontaneous polarization in a specific direction (to provide anisotropy).
しかしながら、セラミックスであるため、分極処理をお
こなっても、残留分極は単結晶の分極にはおよばない。However, since it is a ceramic, the residual polarization does not reach the polarization of a single crystal even if polarization treatment is performed.
他の特性はともかく、この残留分極だけに着目したとし
ても、最もよいときで、８２〜８３％が限度である。そ
して、いったん分極処理を行っても、脱分極をおこしや
すい。そのため、時間を経ると圧電特性が劣化したり、
高応力状態の時には圧電特性が不安定となったりする。Regardless of other characteristics, even if we focus only on this residual polarization, the best case is 82 to 83%. Furthermore, even once polarization treatment is performed, depolarization is likely to occur. Therefore, the piezoelectric properties may deteriorate over time,
In a high stress state, the piezoelectric properties may become unstable.
このようなことから、圧電セラミックスが、単結晶に対
して素子形状の自由度が大きく、製造コストも低いとい
う利点を備えていても、いまひとつ飛躍的に利用が拡大
しないという問題があった〔発明の目的〕
この発明は、以上の事情に鑑みてなされたちのであって
、圧電機能を利用した電子部品の小型軽量化を可能にす
る高性能の圧電セラミックスを得ることができる製法を
提供することを目的としている。For this reason, even though piezoelectric ceramics have the advantage of having a greater degree of freedom in element shape than single crystals and lower manufacturing costs, there is a problem that the use of piezoelectric ceramics has not expanded dramatically. [Purpose] The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a manufacturing method that can obtain high-performance piezoelectric ceramics that make it possible to reduce the size and weight of electronic components using piezoelectric functions. The purpose is
以上の目的を達成するため、発明者らは、セラミックス
粉体の形状、配向性と、圧電セラミックスの性能につい
て検討を行った。その結果、セラミックス粉体として、
形状異方性を有し、かつ、特定の形状方向に分極容易軸
を有するものを使用し、それを配向させれば圧電セラミ
ックスの性能が向上することを見出した。ところが、一
般に行われている押し出し法やプレス法によって圧電セ
ラミックスを製造したのでは、配向度が充分に得られず
、圧電特性をいちじるしく向上させることもできない。In order to achieve the above object, the inventors investigated the shape and orientation of ceramic powder and the performance of piezoelectric ceramics. As a result, as ceramic powder,
We have found that the performance of piezoelectric ceramics can be improved by using a material that has shape anisotropy and has an axis of easy polarization in a specific shape direction and orienting it. However, if piezoelectric ceramics are manufactured by the commonly used extrusion method or pressing method, a sufficient degree of orientation cannot be obtained and the piezoelectric properties cannot be significantly improved.
そこで、さらに検討を重ねた結果、この発明を完成した
。Therefore, as a result of further study, this invention was completed.
したがって、この発明は、セラミックス粉体を主成分と
する成形体を加熱焼成する工程を含んだ圧電セラミック
スの製法であって、前記セラミックス粉体として、形状
異方性を有し、かつ、特定の形状方向に分極容易軸を有
するものを使用するとともに、前記加熱焼成時に前記成
形体に直流電界を印加することを特徴とする圧電セラミ
ックスの製法を要旨としている。Therefore, the present invention provides a method for producing piezoelectric ceramics, which includes a step of heating and firing a molded body containing ceramic powder as a main component, in which the ceramic powder has shape anisotropy and has a specific shape. The gist of the present invention is a method for producing piezoelectric ceramics, characterized in that a piezoelectric ceramic having an axis of easy polarization in the shape direction is used, and a direct current electric field is applied to the molded body during the heating and firing process.
以下に、この発明を、その一実施例をあられす図面を参
照しつつ、くわしく説明する。Hereinafter, one embodiment of the present invention will be explained in detail with reference to the accompanying drawings.
まず、第１図にみるように、形状異方性を有し、かつ、
特定の形状方向に分極容易軸を有するセラミックス粉体
を主成分とする成形体ｌを用意する。ここでいう、形状
異方性を有し、がっ、特定の形状方向に分極容易軸を有
するセラミックス粉体とは、たとえば、針状や繊維状、
あるいは、板状で、かつ、分極容易軸が、その特定方向
に向いているものをあられしている。このようなセラミ
ックス粉体としては、これに限られるものではないが、
たとえばチタン酸バリウムの針状結晶等があげられる。First, as shown in Figure 1, it has shape anisotropy and
A molded body 1 whose main component is ceramic powder having an axis of easy polarization in a specific shape direction is prepared. Here, the ceramic powder that has shape anisotropy and has an axis of easy polarization in a specific shape direction is, for example, acicular, fibrous,
Alternatively, it is plate-shaped and the axis of easy polarization is oriented in a specific direction. Such ceramic powders include, but are not limited to,
For example, needle-shaped crystals of barium titanate can be mentioned.
また、成形体ｌとしては、前記セラミックス粉体を所定
の形状を有する型内空間に入れて加圧成形した微粒子成
形体や、この微粒子成形体を焼成温度以下で加熱焼結し
た仮焼体、あるいは、前記セラミックス粉体を樹脂、可
塑剤、溶剤等と混合してスラリーにし、それをドクター
ブレード法等で成形した、いわゆる、グリーンシート等
があげられる。成形体とし′ζは、この他にも、前記微
粒子成形体を仮焼したあと粉砕して粉体とし、それを再
度加圧成形して得られるものもあるが、このものは前記
仮焼体の粉砕時に、セラミックス粉体の形状異方性が破
壊され、粉体粒子が丸くなってしまう恐れがあるため、
この発明には好ましくない。The molded body l may be a fine particle molded body obtained by placing the ceramic powder in a mold space having a predetermined shape and press-molded, or a calcined body obtained by heating and sintering this fine particle molded body at a temperature below the firing temperature. Another example is a so-called green sheet, which is obtained by mixing the ceramic powder with a resin, a plasticizer, a solvent, etc. to form a slurry, and molding the slurry using a doctor blade method or the like. In addition to this, the compacted body ′ζ can also be obtained by calcining the fine particle compact, pulverizing it into a powder, and press-molding it again. When pulverizing, the shape anisotropy of the ceramic powder may be destroyed and the powder particles may become round.
This is not preferred for this invention.
この成形体ｌの、分極容易軸Ｃ軸方向に直交する２つの
面に導電ペースト２．２を塗布する。さらに、リード線
４付きの２枚の金属板３，３で両面を挟むようにして押
さえる。導電ペースト２の材質としては、種々のものが
考えられるが、高温で連発したり、表面張力が大きすぎ
て玉にならないものが好ましい。このようなものとして
は、経験上、ガラスバインダーを含まないものが良く、
その中でも特に、白金が好ましい。また、金属板３およ
びリード線４としても、耐熱性等の点から、白金を使用
することが好ましい。これをたとえば、図にみるような
マグネシア製ルツボ５に入れ、試料の上にチタン酸バリ
ウム製の焼結体６を押さえ仮としてのせ、ルツボのふた
７をする。リード綿４，４が炉外へ出るようにして、ル
ツボ５を電気炉中に入れ、炉を昇温する。温度が上昇し
て成形体が焼成状態になっている時に、リード線４．４
に高電圧を加えて直流電界を印加し、電界印加方向にＣ
軸を配向させる。なお、ここで、成形体ｌが焼成状態に
なる温度とは、この成形体ｌが微粒子成形体やグリーン
シートである場合には、結晶粒が成長する温度（チタン
酸バリウムでは約１１００〜１３００℃以上）をさし、
仮焼体では焼結が発生する温度をさす。また、直流電界
を印加するタイミングとしては、加熱焼成の全工程、す
なわち、昇温開始から、降温終了までの間ずっと印加し
つづけるようであってもよいし、昇温時のみ、あるいは
、降温時のみに印加するようであってもよい。要するに
、前記成形体１が焼成状態になっている間、すなわち、
前述した温度の間に、成形体１に直流電界が印加される
のであれば、そのタイミングは、特に限定されないので
ある。A conductive paste 2.2 is applied to two surfaces of this molded body l perpendicular to the easy polarization axis C-axis direction. Furthermore, both surfaces are held between two metal plates 3 and 3 with lead wires 4 attached thereto. Although various materials can be considered for the conductive paste 2, it is preferable to use a material that does not splatter at high temperatures or has too high a surface tension to form beads. From my experience, it is best to use something that does not contain a glass binder.
Among these, platinum is particularly preferred. Further, it is preferable to use platinum for the metal plate 3 and the lead wires 4 from the viewpoint of heat resistance and the like. For example, this is placed in a crucible 5 made of magnesia as shown in the figure, a sintered body 6 made of barium titanate is placed on top of the sample as a temporary press, and a lid 7 of the crucible is closed. The crucible 5 is placed in an electric furnace so that the lead cottons 4, 4 come out of the furnace, and the temperature of the furnace is raised. When the temperature rises and the molded body is in the firing state, the lead wire 4.4
A high voltage is applied to apply a DC electric field, and C
Orient the axis. In addition, here, the temperature at which the compact 1 becomes a fired state is the temperature at which crystal grains grow (approximately 1100 to 1300°C for barium titanate) when the compact 1 is a fine particle compact or a green sheet. above),
For calcined bodies, it refers to the temperature at which sintering occurs. Furthermore, the timing of applying the DC electric field may be such that it continues to be applied throughout the entire heating and firing process, from the start of temperature rise to the end of temperature fall, or only during temperature rise, or during temperature fall. It may be applied only to In short, while the molded body 1 is in the firing state, that is,
As long as the DC electric field is applied to the molded body 1 during the above-mentioned temperature, the timing is not particularly limited.
以上のように直流電界を印加しながら、焼成を行うと、
焼成前には第２図（ａｌにみるように、成形体１中にラ
ンダムに配置されていたセラミックス粉体８が、焼成後
には、第２図（ｂ）にみるように、並列に配向される。When firing is performed while applying a DC electric field as described above,
Before firing, the ceramic powders 8 were randomly arranged in the molded body 1 as shown in FIG. 2(a), but after firing, they were oriented in parallel as shown in FIG. 2(b). Ru.
これは、セラミックス粉体８が、前述したように、特定
の形状方向（図の実施例では短軸方向）に分極容易軸（
Ｃ軸）を有するためである。そして、このことによって
、圧電セラミックスの配向度は向上し、高性能化が可能
となる。また、前記Ｃ軸と直交するａ軸も配向して、全
体として圧電セラミックスの長さ方向に正方晶が形成さ
れるため、経時変化によって圧電特性が劣化することも
なくなる。This is because, as mentioned above, the ceramic powder 8 has an easy polarization axis (
This is because it has a C axis). This improves the degree of orientation of the piezoelectric ceramics, making it possible to achieve higher performance. In addition, since the a-axis orthogonal to the C-axis is also oriented, and a tetragonal crystal is formed in the length direction of the piezoelectric ceramic as a whole, the piezoelectric properties do not deteriorate due to changes over time.
なお、図においては、以上のようなセラミックス粉体を
一本の線であられしているが、これは、実際の大きさを
あられしているのではなく、セラミックス粉体の配向方
向をわかりやすくするために、図式化してあられしたも
のである。In addition, in the figure, the ceramic powder as described above is marked with a single line, but this does not indicate the actual size, but is intended to make it easier to understand the direction of orientation of the ceramic powder. In order to do so, it was created in a diagram.
これまでは、図の実施例にもとづいてのみ、この発明の
圧電セラミックスの製法を説明してきたが、この発明は
図の実施例に限定されるものではない。たとえば、成形
体ｌの加熱焼成を行うルツボ５が必ずしも図のような形
状である必要はなく、成形体ｌの形状に応じたルツボを
使用すればよい。さらにいえば、成形体１の加熱焼成を
必ずしも、図のようなルツボ中で行う必要もないのであ
る。Up to now, the method for producing piezoelectric ceramics of the present invention has been explained only based on the illustrated embodiment, but the present invention is not limited to the illustrated embodiment. For example, the crucible 5 for heating and firing the compact 1 does not necessarily have to have the shape shown in the figure, and a crucible that matches the shape of the compact 1 may be used. Furthermore, it is not necessary to heat and sinter the molded body 1 in a crucible as shown in the figure.
以下に、この発明の実施例について、比較例とあわせて
説明する。Examples of the present invention will be described below along with comparative examples.
（実施例１）
直径１〜５μｍ、長さ２０〜８０μｍの針状チタン酸カ
リウム粉末と水酸化バリウムとを混合し、オートクレー
ブ中に入れて１５０℃、２４時間の加熱を行った。この
あと、オートクレーブ中の温度を５℃／分の降温速度で
降温していって室温にもどし、反応物を得た。得られた
反応物に対し、ろ過、水洗の処理を行ったあと、８０“
Ｃ１２４時間の乾燥を行い、直径１〜２μｍ、長さ２０
〜７０ｍの針状のチタン酸バリウム粉体を得た。これを
、内径２０酊の型内空間に入れ、１０００ ｋｇ／ ｃ
ｎ！の圧力を加えて成形し、外径２ｏ鶴、厚み１１重の
成形体を得た。得られた成形体の両面、すなわち、分極
容易軸に直交する２つの面に白金ペースト（エンゲルハ
ード社製Ａ−３４４４）を塗布し、１００℃、２時間の
乾燥を行った。さらに、この成形体の両面を、白金線（
リード線）が接続された直径３０鶴、厚み０．６ ｍｍ
の白金プレート（金属板）で挟み、マグネシア製のルツ
ボ中に入れた。この試料の上に、直径３５ｍｍ、厚み２
０ｍｍのチタン酸バリウム製焼結体をのせて、白金プレ
ートと成形体表面の白金ペーストとの密着を良くするよ
うにした。このあと、ルツボのふたをし、白金線が炉外
へ出るようにして電気炉中に入れ、白金線を電源と接続
して、成形体に１５００Ｖの直流電界を印加しながら、
炉内の温度を、２００’Ｃ／時の昇温速度で昇温した。(Example 1) Acicular potassium titanate powder having a diameter of 1 to 5 μm and a length of 20 to 80 μm was mixed with barium hydroxide, and the mixture was placed in an autoclave and heated at 150° C. for 24 hours. Thereafter, the temperature in the autoclave was lowered at a rate of 5° C./min to room temperature to obtain a reaction product. The obtained reaction product was filtered and washed with water, and then
Dry for 124 hours, diameter 1-2 μm, length 20
A barium titanate powder having a needle shape of ~70 m was obtained. This is placed in a mold space with an inner diameter of 20 mm and weighs 1000 kg/c.
n! A molded article having an outer diameter of 2 degrees and a thickness of 11 layers was obtained. Platinum paste (A-3444 manufactured by Engelhard) was applied to both surfaces of the obtained molded body, that is, two surfaces perpendicular to the axis of easy polarization, and dried at 100° C. for 2 hours. Furthermore, both sides of this molded body were coated with platinum wire (
30 wires in diameter and 0.6 mm thick with lead wires connected
It was sandwiched between two platinum plates (metal plates) and placed in a magnesia crucible. On top of this sample, a diameter of 35 mm and a thickness of 2
A 0 mm barium titanate sintered body was placed on the molded body to improve adhesion between the platinum plate and the platinum paste on the surface of the molded body. After that, the crucible was covered, placed in an electric furnace with the platinum wire coming out of the furnace, the platinum wire was connected to a power source, and while applying a 1500V DC electric field to the molded body,
The temperature inside the furnace was increased at a rate of 200'C/hour.
炉内の温度が１４００ ’Ｃに達したときに昇温をやめ
、この温度を５時間保持し、加熱焼成を行った。このあ
と、２００°Ｃ／時の降温速度で炉内の温度を下げ、室
温まで冷却して圧電セラミックスを得た。When the temperature in the furnace reached 1400'C, the temperature increase was stopped and this temperature was maintained for 5 hours to carry out heating and firing. Thereafter, the temperature inside the furnace was lowered at a temperature lowering rate of 200°C/hour, and the mixture was cooled to room temperature to obtain piezoelectric ceramics.
（実施例２）
前記実施例１で得られた針状のチタン酸バリウム粉体を
、実施例１と同様にして、直径２０鰭。(Example 2) The needle-shaped barium titanate powder obtained in Example 1 was prepared in the same manner as in Example 1, and was made into a powder having a diameter of 20 fins.
厚み１ｍｌに成形したあと、無電界で仮焼して成形体を
得た。この成形体を使用して、実施例１と同様にして、
１５００Ｖの直流電界下で焼成を行い、圧電セラミック
スを得た。After molding to a thickness of 1 ml, it was calcined without an electric field to obtain a molded body. Using this molded body, in the same manner as in Example 1,
Firing was performed under a DC electric field of 1500V to obtain piezoelectric ceramics.
（実施例３）
電界の印加を１４００℃到達まででやめ、あとは無電界
で焼成を行った以外は、実施例２と同様にして、圧電セ
ラミックスを得た。(Example 3) A piezoelectric ceramic was obtained in the same manner as in Example 2, except that the application of the electric field was stopped after reaching 1400° C., and the firing was then performed without an electric field.
（実施例４）
電界の印加を降温過程の１２５０℃以降で行った以外は
、実施例２と同様にして、圧電セラミックスを得た。(Example 4) A piezoelectric ceramic was obtained in the same manner as in Example 2, except that the electric field was applied after 1250° C. during the cooling process.
（比較例１）
電界を全く印加しなかった以外は、実施例１と同様にし
て、圧電セラミックスを得た。(Comparative Example 1) A piezoelectric ceramic was obtained in the same manner as in Example 1 except that no electric field was applied.
（比較例２）
電界を全く印加しなかった以外は、実施例２と同様にし
て、圧電セラミックスを得た。(Comparative Example 2) A piezoelectric ceramic was obtained in the same manner as in Example 2 except that no electric field was applied.
（比較例３）
前記実施例１で得られた針状のチタン酸バリウム粉体を
仮焼したあと、ボールミルで粉砕し、粉体を得た。得ら
れた粉体を電子顕微鏡で観察したところ、形状異方性が
破壊されて球状になっていた。この粉体を実施例１と同
様にして成形したあと、無電界で焼成して圧電セラミッ
クスを得た。(Comparative Example 3) The acicular barium titanate powder obtained in Example 1 was calcined and then ground in a ball mill to obtain a powder. When the obtained powder was observed under an electron microscope, it was found that the shape anisotropy was destroyed and it became spherical. This powder was molded in the same manner as in Example 1, and then fired without an electric field to obtain piezoelectric ceramics.
（比較例４）
加熱焼成時に１５００Ｖの直流電界を印加した以外は、
比較例３と同様にして圧電セラミックスを得た。(Comparative Example 4) Except for applying a DC electric field of 1500 V during heating and firing,
Piezoelectric ceramics were obtained in the same manner as in Comparative Example 3.
（実施例５）
前記実施例１で得られた針状のチタン酸バリウム粉体１
００重量部（以下、「部」と記す）に対し、ポリビニル
ブチラール樹脂８部、フタル酸エステル４部、ブタノー
ル２０部およびトリクロルエチレン５０部を加えてディ
スペンサーで混合し、スラリーを得た。このスラリーを
ドクターブレード法によって厚み２００μｍのグリーン
シートに成形し、それを３０鶴角の大きさに切断したも
のを３枚重ねて８００ｋｇ／ｃｏ！の圧力で成形して成
形物を得た。得られた成形物を空気中で３００℃。(Example 5) Acicular barium titanate powder 1 obtained in Example 1
00 parts by weight (hereinafter referred to as "parts"), 8 parts of polyvinyl butyral resin, 4 parts of phthalate ester, 20 parts of butanol, and 50 parts of trichlorethylene were added and mixed in a dispenser to obtain a slurry. This slurry was formed into a green sheet with a thickness of 200 μm using the doctor blade method, which was then cut into 30 square pieces and three sheets stacked one on top of the other, weighing 800 kg/co! A molded product was obtained by molding at a pressure of . The obtained molded product was heated in air at 300°C.
７時間加熱して有機物を除去し、成形体を得た。The organic matter was removed by heating for 7 hours to obtain a molded body.
この成形体を用いて、実施例１と同様にして圧電セラミ
ックスを得た。A piezoelectric ceramic was obtained using this molded body in the same manner as in Example 1.
実施例１〜５および比較例１〜４で得られた圧電セラミ
ックスに銀電極を焼付けをしたあと、８０℃で１．５
Ｋ Ｖ ／ ｕ＋の電界を印加して分極処理を行った。After baking silver electrodes on the piezoelectric ceramics obtained in Examples 1 to 5 and Comparative Examples 1 to 4, the temperature was 1.5 at 80°C.
Polarization treatment was performed by applying an electric field of K V / u+.
この圧電セラミックスについて、電気機械結合係数、電
圧出力係数、圧電ひずみ定数および比誘電率の測定をお
こなった。結果は下馳の第１表の通りである。第１表の
結果から明らかなように、実施例１〜５の圧電セラミッ
クスは、電気機械結合係数に３１＋ Ｋ３３や、電圧
出力係数ｇ ３１１ｇ３ｆｆ、圧電ひずみ定数ｄ３１＋
ｄ３３の値が、非常にすぐれたものとなっている。The electromechanical coupling coefficient, voltage output coefficient, piezoelectric strain constant, and dielectric constant of this piezoelectric ceramic were measured. The results are shown in Table 1 of Shimohase. As is clear from the results in Table 1, the piezoelectric ceramics of Examples 1 to 5 have an electromechanical coupling coefficient of 31+K33, a voltage output coefficient g of 311g3ff, and a piezoelectric strain constant of d31+
The value of d33 is extremely excellent.
このことから、この発明で得られた圧電セラミックスは
、圧力センサや超音波センサ素子として好適な材料でる
ことがわかる。また、以上の試料について、その配向度
を測定したところ、実施例１〜５では、明らかに配向度
が良くなっていた。したがって、この実施例１〜５の圧
電セラミックスは、分極が容易で、しかも、経時変化に
よる脱分極がないものであることがわかった。This shows that the piezoelectric ceramic obtained by the present invention is a suitable material for pressure sensors and ultrasonic sensor elements. Moreover, when the degree of orientation of the above samples was measured, it was found that the degree of orientation was clearly improved in Examples 1 to 5. Therefore, it was found that the piezoelectric ceramics of Examples 1 to 5 were easily polarized and did not undergo depolarization due to changes over time.
ここで、配向度の評価は、分極処理をおこなう前にＸ線
回折法を使って行った。銅（Ｃｕ）をターゲットとし、
Ｋｄｌ線を使い、Ｃ軸ＭＯＯ２）軸）とａ軸（（２００
）軸）におけるピーク面積から配向度を算出した。Here, the degree of orientation was evaluated using an X-ray diffraction method before the polarization treatment. Targeting copper (Cu),
Using the Kdl line, calculate the C axis (MOO2) axis) and the a axis ((200
The degree of orientation was calculated from the peak area in ) axis).
比較例１のセラミックス成形体をボールミルで粉砕して
得られた試料のＸ線ピークを使って、ＰＯ（下式により
求められる）を得る。Using the X-ray peak of a sample obtained by pulverizing the ceramic molded body of Comparative Example 1 with a ball mill, PO (calculated by the following formula) is obtained.
Ｐｏ＝（（００２）軸におけるピーク面積）÷（（００
２）軸におけるピーク面積＋（２００）軸におけるピー
ク面積）
実施例１〜５のそれぞれで得られた試料のＸ′ｂＡピー
クを使って、それぞれのＰｓ（下式により求める）を得
る。Po=(peak area on (002) axis)÷((00
2) Peak area on axis+peak area on (200) axis) Using the X'bA peak of the samples obtained in each of Examples 1 to 5, each Ps (determined by the formula below) is obtained.
Ｐｓ＝（（００２）軸におけるピーク面積）÷（（００
２）軸におけるピーク面積＋（２００）軸におけるピー
ク面積）
そしてこのようにして得られたＰｏとＰｓから配向度を
表す数値Ｘｃ （＝Ｐｓ／Ｐｏ）を求めた〔発明の効果
〕
以上詳述したように、この発明にかかる製法によって製
造された圧電セラミックスは高い配向度を有しているの
で、単結晶に近いすぐれた圧電特性を備えており、しか
も、セラミックスとしての利点を全く損なわれることも
ない。そのため、この圧電セラミックスを用いる電子部
品の性能向上はもちろんのこと小型軽量化をはかること
ができるのである。Ps = (peak area on (002) axis) ÷ ((00
2) Peak area on the axis + peak area on the (200) axis) Then, the numerical value Xc (=Ps/Po) representing the degree of orientation was determined from Po and Ps obtained in this way [Effects of the invention] Detailed explanation above As described above, the piezoelectric ceramics manufactured by the manufacturing method according to the present invention have a high degree of orientation, so they have excellent piezoelectric properties close to those of single crystals, and furthermore, they do not lose any of the advantages of ceramics. Nor. Therefore, it is possible to not only improve the performance of electronic components using this piezoelectric ceramic, but also to reduce their size and weight.
第１図はこの発明における直流電界の印加および焼成の
一実施例をあられす側面断面図、第２図は焼成時におけ
るセラミックス粉体の挙動を説明する図であって、第２
図（ａｌは焼成前の成形体内におけるセラミックス粉体
の状態を説明する説明図、第２図（ｂｌは焼成後の成形
体内におけるセラミックス粉体の状態を説明する説明図
である。
ｌ・・・成形体 ８・・・セラミックス粉体代理人 弁
理士 松 本 武 彦
第１図
第２図
（ａ）（ｂ）FIG. 1 is a side sectional view showing an example of application of a DC electric field and firing according to the present invention, and FIG. 2 is a diagram illustrating the behavior of ceramic powder during firing.
Figure (al is an explanatory diagram explaining the state of ceramic powder in the molded body before firing, FIG. 2 (bl is an explanatory diagram explaining the state of ceramic powder in the molded body after firing. l... Molded object 8... Ceramic powder agent Patent attorney Takehiko Matsumoto Figure 1 Figure 2 (a) (b)
Claims (2)
成する工程を含んだ圧電セラミックスの製法であって、
前記セラミックス粉体として、形状異方性を有し、かつ
、特定の形状方向に分極容易軸を有するものを使用する
とともに、前記加熱焼成時に前記成形体に直流電界を印
加することを特徴とする圧電セラミックスの製法。(1) A method for producing piezoelectric ceramics, which includes a step of heating and firing a molded body containing ceramic powder as a main component,
The ceramic powder is characterized in that it has shape anisotropy and has an axis of easy polarization in a specific shape direction, and a DC electric field is applied to the molded body during the heating and firing. Manufacturing method of piezoelectric ceramics.
ートからなる群より選ばれたうちの１つである特許請求
の範囲第１項記載の圧電セラミックスの製法。(2) The method for producing piezoelectric ceramics according to claim 1, wherein the molded body is one selected from the group consisting of a fine particle molded body, a calcined body, and a green sheet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61014314A JPS62172776A (en) | 1986-01-25 | 1986-01-25 | Manufacture of piezoelectric ceramics |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61014314A JPS62172776A (en) | 1986-01-25 | 1986-01-25 | Manufacture of piezoelectric ceramics |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS62172776A true JPS62172776A (en) | 1987-07-29 |
Family
ID=11857632
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61014314A Pending JPS62172776A (en) | 1986-01-25 | 1986-01-25 | Manufacture of piezoelectric ceramics |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62172776A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005044926A (en) * | 2003-07-25 | 2005-02-17 | Kyocera Corp | Stacked piezoelectric element and actuator, and printing head |
| JP2008266085A (en) * | 2007-04-23 | 2008-11-06 | Daiken Kagaku Kogyo Kk | NEEDLE CRYSTAL OF BaTiO3, PRECURSOR THEREOF, METHODS FOR PRODUCING THEM AND GREEN SHEET |
| JP2010251766A (en) * | 2001-11-15 | 2010-11-04 | Fujifilm Dimatix Inc | Ink jet printing module with orientation-determined piezoelectric film |
-
1986
- 1986-01-25 JP JP61014314A patent/JPS62172776A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010251766A (en) * | 2001-11-15 | 2010-11-04 | Fujifilm Dimatix Inc | Ink jet printing module with orientation-determined piezoelectric film |
| JP2005044926A (en) * | 2003-07-25 | 2005-02-17 | Kyocera Corp | Stacked piezoelectric element and actuator, and printing head |
| JP4658459B2 (en) * | 2003-07-25 | 2011-03-23 | 京セラ株式会社 | Multilayer piezoelectric element, actuator, print head, and multilayer piezoelectric element manufacturing method |
| JP2008266085A (en) * | 2007-04-23 | 2008-11-06 | Daiken Kagaku Kogyo Kk | NEEDLE CRYSTAL OF BaTiO3, PRECURSOR THEREOF, METHODS FOR PRODUCING THEM AND GREEN SHEET |
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