Denso Corporation

Nippon Soken, Inc.

Other

Nippondenso Co., Ltd.

Kabushiki Kaisha Toyota Chuo Kenkyusho

Toshiatsu Nagaya

Takashi Yamamoto

Hitoshi Shindo

Atsuhiro Sumiya

Eturo Yasuda

Tatsuhiko Nonoyama

Hisaaki Takao

Kazumasa Takatori

Yasuyoshi Saito

Takahiko Homma

Masaya Nakamura

Akira Fujii

Hirokatsu Mukai

Naoto Miwa

Makoto Hori

Hitoshi Niwa

Masatoshi Ikeda

Etsuro Yasuda

Nobuo Kamiya

Hiroaki Makino

Takumi Kataoka

Daisuke Shibata

Noriaki Kihara

Yasunori Suzuki

Kumi Sawaguchi

Kouji Noda

Youta Iwamoto

Itsuhei Ogata

Ryoji Kai

A multilayered piezoelectric element and a method of producing the multilayered piezoelectric element are disclosed. The multilayered piezoelectric element is made of piezoelectric ceramic layers and electrode formation layers which are alternately laminated. The piezoelectric ceramic layers are made of crystal oriented ceramic as polycrystalline material. The crystal oriented ceramic is made mainly of an isotropic perovskite type compound in which the specific {100} crystal plane of each of crystal grains that form the polycrystalline material is oriented. The electrode formation layers have electrode parts forming inner electrodes containing a conductive metal. The isotropic perovskite type compound is expressed by a general formula (1):[Ag{Li(KNa)}](NbTaSb)O&#x2003;&#x2003;(1),where 0&#x2266;x&#x2266;0.2, 0&#x2266;y&#x2266;1, 0&#x2266;z&#x2266;0.4, 0&#x2266;w&#x2266;0.2, x+z+w&#x3e;0, 0&#x3c;h&#x2266;0.05, 0.94&#x2266;j&#x2266;1, and 0&#x2266;k&#x2266;0.5).

Multilayered piezoelectric element and method of producing the same

A stacked piezoelectric element obtained by alternately stacking a piezoelectric ceramic layer and an electrode layer, wherein said electrode layer mainly comprises an electrically conducting base metal electrode material, and the region held between the electrode layer positioned at the top of each ceramic layer and the electrode layer positioned at the bottom of each ceramic layer contains a material having no piezoelectricity, in which a constituent element of said material having no piezoelectricity is uniformly dispersed so as not to have local distribution of a distributed strength exceeding 2 times the distributed strength which is distributed in a largest number of places and is not 0.

Stacked piezoelectric element and production method thereof

To provide a production method of a polycrystalline ceramic body with excellent density, a preparation step, a mixing step, a forming step and a heat-treating step are performed. In the preparation step, a coarse particle ceramic powder, and a fine particle powder having an average particle diameter of &#x2153; or less of the average particle diameter of the coarse particle ceramic powder are prepared. In the mixing step, the coarse particle ceramic powder and the fine particle powder are mixed to produce a raw material mixture. In the forming step, the raw material mixture is formed to a shaped body. In the heat-treating step, the shaped body is heated and thereby sintered to produce a polycrystalline ceramic body. In the heat-treating step, a temperature elevating process and a first holding process are performed and at the same time, a second holding process and/or a cooling process are performed. In the temperature elevating process, heating is started to elevate the temperature and in the first holding process, the shaped body is held at a temperature T&#xb0; C. In the second holding process, the shaped body is held at a temperature T&#xb0; C. lower than the temperature T&#xb0; C. In the cooling process, the shaped body is cooled at a temperature dropping rate of 60&#xb0; C./h or less from the temperature T&#xb0; C.

Production method of polycrystalline ceramic body

A piezoelectric actuatorincludes a piezoelectric element, which has a pair of electrodes formed on the surface of a piezoelectric ceramic member, as a drive source. The piezoelectric actuatorsatisfies at least one of the following requirements (a) to (c):

Piezoelectric actuator

The piezoelectric actuator includes a piezoelectric element () including a sheet of piezoelectric ceramic and electrodes formed at least part of the surface of the sheet of piezoelectric ceramic, and a holding member () holding the piezoelectric element ();

A method of producing a laminated dielectric element of high quality, free of delamination. A method of producing a laminated dielectric elementby alternately laminating dielectric ceramic layersand base metal electrode layerscomprising the steps of printing electrodes by applying a paste material for the base metal electrodes onto the surfaces of at least one side of the ceramic green sheets, laminating and press-adhering the ceramic green sheets to fabricate a laminate thereof, dewaxing the laminate, reducing the electrodes to form base metal electrode layers by heating the laminate while flowing an atmospheric gas and by reducing the paste material for the base metal electrodes, and sintering the laminate. In the step of reducing the electrodes, the paste material for the base metal electrodes is so reduced that the amount of the base metal oxide remaining in the base metal electrode layers is not larger than 20% by weight and that the amount of lead liberated from the ceramic material is not larger than 30 atomic % within 5000 &#x212b; from the surfaces of the base metal electrode layers.

Method for fabricating laminate-type dielectric element

This invention provides a piezoelectric ceramic composition that does not contain lead, can be sintered at a normal pressure and is excellent in at least one of a piezoelectric constant, an electro-mechanical coupling coefficient, a dielectric loss, a relative dielectric constant and a Curie point, its production method, and a piezoelectric device and a dielectric device each utilizing the piezoelectric ceramic composition. The invention relates to a piezoelectric composition expressed by the general formula {Li(KNa)}(NbSb)O, each of x, y and z respectively falling within composition ranges of 0&#x2266;x&#x2266;0.2, 0&#x2266;y&#x2266;1.0 and 0&#x2266;z&#x2266;0.2 (with the exception of x=z=0), and its production method. The invention further relates to a piezoelectric device having a piezoelectric body formed of the piezoelectric ceramic composition described above and a dielectric device having a dielectric body formed of the piezoelectric ceramic composition described above.

Piezoelectric ceramic composition, its production method, and piezoelectric device and dielectric device

This invention provides a piezoelectric ceramic composition that does not contain lead, can be sintered at a normal pressure and has a high electro-mechanical coupling coefficient and a small dielectric loss, its production method, and a piezoelectric device utilizing the piezoelectric ceramic composition. The invention relates to a piezoelectric composition containing a compound expressed by the general formula {Li(KNa)}(NbTa)O, each of x, y and z respectively falling within composition range of 0&#x2266;x&#x2266;0.2, 0&#x2266;y&#x2266;1.0 and 0&#x2266;z&#x2266;0.4, as its main component, and further containing nickel or a nickel-containing compound. To provide a piezoelectric device that does not contain lead, can be sintered at a normal pressure and has a high electro-mechanical coupling coefficient Kp and a small dielectric loss, the piezoelectric ceramic composition of the invention is expressed by the general formula {Li(KNa)}(NbTa(MnW)O, each of x, y, z and n respectively falling within a composition range of 0&#x2266;x&#x2266;0.2, 0&#x2266;y&#x2266;1.0, 0&#x2266;z&#x2266;0.4 and 0&#x3c;n&#x2266;0.1.

Piezoelectric ceramic composition, its production method and piezoelectric device

A piezoelectric ceramic composition not containing lead, able to be sintered at ordinary pressure, and superior to the past in at least one of the properties unique to piezoelectric ceramic compositions such as the piezoelectric dconstant, that is, a piezoelectric ceramic composition having a compound of a general formula {Li(KNa)}(NbTaSb)Owhere x, y, z, and w are in the ranges of 0&#x2266;x&#x2266;0.2, 0&#x2266;y&#x2266;1, 0&#x3c;z&#x2266;0.4, and 0&#x3c;w&#x2266;0.2 as a main ingredient, where the piezoelectric ceramic composition contains at least one metal element selected from (1) palladium, silver, gold, ruthenium, rhodium, rhenium, osmium, iridium, and platinum, (2) nickel, iron, manganese, copper, and zinc, or (3) magnesium, calcium, strontium, and barium as an added element, and a method of production of the same and a piezoelectric element and dielectric element utilizing that piezoelectric ceramic composition.

Piezoelectric ceramic composition and method of production of same, piezoelectric element, and dielectric element

This invention provides a method of producing a laminate type dielectric device free from peeling of an electrode layer and a ceramic layer and from voids in both electrode layer and ceramic layer, and an electrode paste material. The invention relates also to an electrode paste material for constituting electrode layers of a laminate type dielectric device produced by at least the steps of alternately laminating ceramic layerscontaining a lead element as a constituent component and electrode layers, and degreasing and baking the laminate, wherein the electrode paste material contains CuO as a principal component of a starting material of an electrically conductive material, a solvent, a binder, and a cooperative material consisting of at least one kind of the main components constituting the ceramic layer

Production method for laminate type dielectric device and electrode paste material

This invention provides a stacked ceramic body that prevents reaction between components of dielectric layers and components of electrode layers of an unsintered stacked body during sintering and in which both components do not easily form a liquid phase, and a production method of such a stacked ceramic body. A print portionis formed on a green sheetcontaining lead by use of an electrode paste consisting of copper oxide as its main component. A desired number of print sheetsare stacked to give an unsintered stacked body. Degreasing is conducted in an atmosphere to degrease organic components. The print portionis subjected to reducing treatment in a reducing atmosphere containing hydrogen and is converted to a print portioncontaining copper as its main component. The unsintered stacked bodyis sintered in a reducing atmosphere. Dielectric layers containing lead and electrode layers for applying a voltage to the dielectric layers are alternately stacked, and an oxidation portion containing copper is formed in the proximity of a surface of the electrode layer. A thickness of the oxidation portion in a stacking direction is 0.5 to 2 &#x3bc;m and a copper content in the oxidation portion is 1 to 30 wt %.

Stacked ceramic body and production method thereof

This invention provides a method for producing a stacked ceramic body that does not require strict control of an oxygen partial pressure in a sintering gas. To produce a stacked ceramic body by alternately stacking dielectric layer and electrode layers, an unsintered stacked bodyis prepared by alternately stacking unsintered dielectric layers containing a PZT type dielectric material and unsintered electrode layers containing an electrode material, and is sintered in a sintering gas to which a dielectric layer anti-reducing agentand an electrode layer anti-oxidantare introduced. Alternatively, sintering is conducted in a gas containing only the dielectric layer anti-reducing agentor in a gas containing only the electrode layer anti-oxidant

Method for producing stacked ceramic body

A laminate type dielectric device is formed by alternately laminating dielectric ceramic layers and electrode layers and integrally baking the laminate product. The electode layers are mainly made of an electrically conductive base metal material having greater standard Gibbs free energy for the formation of a metal oxide at a baking temperature than that of the ceramic material constituting the dielectric ceramic layers. Segregation of the materials including the electrically conductive base metal material does not occur at portions sandwiched between adjacent positive and negative electrode layers among the dielectric ceramic layers.

Laminate-type dielectric device, a production method and an electrode paste material

A PZT dielectric ceramic material is sintered at a desired low temperature to prevent deterioration of the performance of the base material. An auxiliary oxide is used that is made by adding the oxide of at least one of tungsten and molybdenum to lead oxide in the following proportions:PbO+(WO+MoO)where x+y+z=1, 0.005&#x3c;y+z&#x3c;0.4 and y, z&#x2267;0. 0.5 mol % to 20 mol % of this auxiliary oxide is added to a mixture of a stock material of dielectric ceramic material or its calcination having a composition of ABOtype dielectric ceramic material where 0.9 molar ratio or more lead is included in site A assuming the proportion of site B is 1, and the material is mixed, formed and sintered. The content of tungsten and molybdenum combined is less than 0.098 mole in proportion to 1 mole of lead and the density of the dielectric ceramic material after sintering is 7.5 g/cmlarger. The auxiliary oxide is dispersed in the calcined powder to form a liquid phase at a desired temperature, to accelerate the sintering, thus making it possible to sinter at a lower temperature.

Dielectric ceramic material and method for producing the same

A method of manufacturing large-sized laminated dielectrics of high quality which permit adjustment of the atmosphere during sintering process to be accomplished easily, and which can eliminate the problems such as expansion due to reaction with the atmosphere gas. When a laminated body , consisting of oxide dielectric layers and inner electrode layers having a base metal such as Cu as a main component, is sintered in a reducing atmosphere, a mixed gas having CO gas as a main component and containing optional amount of CO gas and O gas is used. By using the equilibrium system of CO &rlarr;2CO&plus;(1/2)O and adjusting the amounts of CO gas and O gas, oxygen partial pressure in the atmosphere gas can be easily and stably adjusted and fluctuation and variation in the atmosphere can be suppressed.

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Kuwana, Japan

Toshiatsu Nagaya