Kabushiki Kaisha Toyota Chuo Kenkyusho

Denso Corporation

Toyota Jidosha Kabushiki Kaisha

Kazumasa Takatori

Takahiko Homma

Toshiatsu Nagaya

Hisaaki Takao

Tatsuhiko Nonoyama

Yasuyoshi Saito

Masaya Nakamura

Naoyoshi Watanabe

Hideo Sobukawa

Nobuo Kamiya

Takao Tani

Naoto Miyoshi

Oji Kuno

Haruo Doi

Toshihiko Tani

Yoshio Ukyo

Shinji Tsuji

Mitsuru Asai

Shigetaka Wada

Masahiko Sugiyama

Hiroaki Makino

Tsuyoshi Sasaki

Jun Sugiyama

Koichi Yamashita

Masahiko Kato

Akihiko Murakami

Akio Takahashi

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 ();

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

A physical sensor having a pressure sensing layer having such property that electrical resistance is changed by application of a stress, and electrical insulating layers which are integrally formed on opposite two surfaces of the pressure sensing layer, respectively, wherein the pressure sensing layer has a matrix comprising glass, and an electrically conductive particle having electrical conductivity and dispersed in the matrix and preferably, the electrically conductive particle includes RuO, and a thickness of the pressure sensing layer is 1 &#x3bc;m to 200 &#x3bc;m, and it is preferable that one pair of electrodes are disposed on the pressure sensing layer.

Physical sensor

A catalyst support, a catalyst using the catalyst support and a process for producing the same are disclosed. For instance, the catalyst support includes a composite oxide powder produced by spraying and burning a W/O type emulsion, the W/O type emulsion including an aqueous solution dispersed in an organic solvent, the aqueous solution containing aluminum as a major component and at least one co-metallic element in addition to the aluminum. Thus, the catalyst support can be produced less expensively without using any expensive alkoxide. Further, due to the spraying and burning, the composite oxide powder is composed of porous hollow particles which have a very thin shell thickness of dozens of nanometers, and makes the catalyst support which is amorphous and exhibits a large specific surface area. Hence, the catalyst support can maintain the large specific surface area even after a high-temperature durability test. Furthermore, the composite oxide powder includes the co-metallic element which is composited in such a highly dispersed manner that the agglomerated sulfates are less likely to be produced. Therefore, the catalyst support is inhibited from being poisoned by sulfur.

Catalyst support and catalyst and process for producing the same

The present invention provides a hollow oxide particle including a shell wall constituting a hollow room, and the shell wall has a thickness of 20 nm or less. The shell wall may be mainly composed from at least one selected from the group consisting of alumina, spinel, iron oxides, yttrium oxides, and titanium oxides. A process for producing the hollow oxide particle comprises the steps of: forming a Water in Oil (W/O) type emulsion including aqueous microspheres having a each diameter of 100 nm or more, by adding an organic solvent to an aqueous solution dissolving and/or suspending at least one of metal salts and metal compounds; and forming the hollow oxide particle by atomizing the Water in Oil (W/O) type emulsion to burn. When the hollow oxide particle is brought into contact with a water-containing solution, a surface of the shell wall may have a minutely irregular surface.

Hollow oxide particle and process for producing the same

The present method is to produce an active material powder formed of a spinel oxide containing lithium or a layer-structured oxide containing lithium for a lithium secondary battery which is uniform in composition, fine in particle size and free of oxygen defects, and which is unlikely to cause capacity deterioration resulted from repetitive charge/discharge cycles at a high current density. A suspension 1 prepared by suspending an ingredient of the active material powder in a combustible liquid or an emulsion prepared by emulsifying a solution of the ingredient in the combustible liquid is sprayed in a droplet state 15 together with an oxygenic gas 2. The combustible liquid contained in the droplet 15 is burned to have the ingredient therein reacted and to evaporate the solvent. As a result, active material powder 4 formed of the spinel oxide containing lithium is obtained. An active material powder formed of the layer-structured oxide containing lithium is obtained by re-heating the oxide powder that has been generated by spraying and burning the droplet.

Method of producing active material powder for lithium secondary battery

Disclosed is a method for producing oxide powders and complex oxide powders having an oxygen amount smaller than the stoichiometric amount. The method comprises: spraying a combustible liquid that contains at least one raw material of metals capable of having a plural number of valences and compounds of such metals; and firing the raw material to give a powder of an oxide of at least one of said metals. The oxygen amount in the atmosphere in which the combustible liquid containing said raw material is sprayed and fired is smaller than the total of the oxygen amount necessary for the complete combustion of said combustible liquid and the oxygen amount necessary for the conversion of said raw material into an oxide that is the most stable in air at room temperature.

Method for producing oxide powder

A process for producing a powder of composite oxide which includes cerium and zirconium, or which includes cerium, zirconium and further a rare-earth element other cerium. The process includes: dissolving nitrate, sulfate and/or acetate of constituent elements of the composite oxide into water in a predetermined ratio; and spraying and heating a resulting aqueous solution to oxidize the constituent elements of the composite oxide for converting them into a powder of a composite oxide. The thus produced composite oxide powder is micro-fine, homogeneous, and heat resistant.

Process for producing composite oxide powder containing cerium and

A silicon nitride sintered body composed of .alpha.'-silicon nitride and .beta.'-silicon nitride, which are present in the ratio of 0.05-0.50 to 0.50-0.95 in terms of the peak strength ratio of X-ray diffraction, and have very small crystal grain size and specific compositions. The sintered body has high strength and high toughness and is superior in oxidation resistance.

Growing community of inventors

Nagoya, Japan

Kazumasa Takatori