Ngk Spark Plug Company, Limited

Other

Katsuya Yamagiwa

Masato Yamazaki

Takeshi Mitsuoka

Kazushige Ohbayashi

Takayuki Matsuoka

Takeshi Araki

Masahiko Okuyama

Izumi Hirabayashi

Kohei Ito

Manabu Sato

Jun Otsuka

Hideto Yamada

Toshiaki Kurahashi

Takashi Kasashima

Kazuhisa Itakura

Kazuaki Kitamura

Yukihiro Hamaguchi

Takashi Oba

Kohji Okada

Tomohiro Hirata

Masahiko Matsumiya

Yasuhiro Fujii

Hideaki Hiramitsu

Manabu Horiguchi

Ryotaro Tawara

Yuko Hisano

Toshihiro Matsuno

Chisato Murase

A lead-free piezoelectric ceramic composition mainly includes a first crystal phase (KNN phase) and a second crystal phase (NTK phase). In the first crystal phase (KNN phase), a plurality of crystal grains formed of an alkali niobate/tantalate perovskite oxide having piezoelectric characteristics is bound to each other in a deposited state. The second crystal phase (NTK phase) is formed of a compound containing titanium (Ti) and fills spaces between the crystal grains in the first crystal phase.

Lead-free piezoelectric ceramic composition, method for producing same, piezoelectric element using lead-free piezoelectric ceramic composition, ultrasonic processing machine, ultrasonic drive device, and sensing device

A lead-free piezoelectric ceramic composition includes a first crystal phase of alkali niobate/tantalate type perovskite oxide having piezoelectric properties and a second crystal phase of A-Ti&#x2014;B&#x2014;O composite oxide (where the element A is an alkali metal; the element B is at least one of Nb and Ta; and the contents of the element A, the element B and Ti are not zero). Examples of the second crystal phase are those represented by ATiBO, and x preferably satisfies 0&#x2266;x&#x2266;0.15.

Lead-free piezoelectric ceramic composition, piezoelectric element comprising same, knock sensor, and process for production of lead-free piezoelectric ceramic composition

There are provided a piezoelectric ceramic composition that includes a bismuth layer-structured compound, which contains Na, Bi, Co and Ln (lanthanoide), as a main component and a piezoelectric ceramic composition that includes a compound, which contains Na, Bi, Ti, Co and Ln (lanthanoide) and has a NaBiTiOtype crystal structure, as a main component, wherein the piezoelectric ceramic composition has an atomic ratio of 0&#x3c;Ln/(Na+Bi+Ln)&#x2266;0.04.

Piezoelectric ceramic composition and piezoelectric device

The present invention provides a piezoelectric ceramic composition having a high thermal resistance and a high piezoelectric distortion constant and a piezoelectric element using the piezoelectric ceramic composition. The piezoelectric ceramic composition of the present invention contains Na, Bi, Ti, Cr and O, wherein the content ratio of Na, Bi, Ti and Cr in terms of oxides thereof falls within the following composition range: aNaO-bBiO-cTiO-dCrOwhere a, b, c and d are mole fractions; 0.030&#x2266;a&#x2266;0.042; 0.330&#x2266;b&#x2266;0.370; 0.580&#x2266;c&#x2266;0.620; 0&#x3c;d&#x2266;0.017; and a+b+c+d=1. The piezoelectric ceramic composition preferably has a main crystal phase of bismuth layer-structured ferroelectric, more preferably NaBiTiOcrystal. The piezoelectric element of the present invention includes a piezoelectric body formed of the piezoelectric ceramic composition and at least a pair of electrodes held in contact with the piezoelectric body.

Piezoelectric ceramic composition and piezoelectric element made by using the same

A piezoceramic material according to an embodiment of the present invention has a composition represented by Pb{ZrTiSn(SbNb)}Owhere 1.000&#x2266;m&#x2266;1.075, 0.470&#x2266;x&#x3c;0.490, 0.020&#x2266;y&#x2266;0.040, 0&#x3c;n&#x3c;1.000 and 0&#x3c;z&#x2266;0.025 and a crystallite size of 30 to 39 nm.

Piezoceramic material, piezoelectric element and non-resonance knock sensor

There is provided a piezoelectric ceramic composition that contains Na, Bi, Ti and Co wherein the composition ratio of Na, Bi, Ti and Co in terms of oxides thereof is in the following composition range (1):NaO-BiO-TiO-CoO&#x2003;&#x2003;(1)where a, b, c and d are mole fractions; 0.03&#x2266;a&#x2266;0.042; 0.330&#x2266;b&#x2266;0.370; 0.580&#x2266;c&#x2266;0.620; 0&#x3c;d&#x2266;0.017; and a+b+c+d=1.

An aqueous solution of mixed metal acetate including one kind or more of element selected from lanthanide series and yttrium, barium and copper is mixed with trifluoroacetic acid to prepare a solution of mixed metal trifluoroacetate. From a solution of mixed metal trifluoroacetate obtained thus, purified mixed metal trifluoroacetate of which total content of water and acetic acid is 2% by weight or less is prepared. With purified mixed metal trifluoroacetate, an oxide superconductor of excellent performance may be prepared.

Preparing method of oxide superconductor, raw material for oxide superconductor, and preparing method of raw material for oxide superconductor

A dielectric composition is based on a BaO&mdash;MgO&mdash;Nb O system material (BMN system material) having a dielectric constant, &egr;, of about 30, a large Q-value (no-load quality coefficient) and a comparatively small absolute value of the temperature coefficient (&tgr; ) of its resonance frequency but containing no expensive Ta. The dielectric material has a composite perovskite crystal structure as the main crystal phase, wherein a predetermined amount of KNbO is added to a BMN system material. The high frequency characteristics can be further improved by partially replacing Nb with Sb and partially replacing the B site of the perovskite crystal structure with Sn.

Dielectric composition for high frequency resonators

Method of preparing oxide superconductor with purified mixed metal trifluoroacetate

A process for producing a high purity and dense calcium phosphate coating film with bioaffinity on a high strength base, such as a base for a substitute for a hard tissue in a living body, comprising (1) dissolving (a) a salt containing phosphorus, a salt containing calcium, and a chelating agent capable of coordinating to either one or both of the metallic ions of these salts or (b) a chelate compound containing at least one of phosphorus and calcium and a salt containing the other in a solvent to prepare a sediment-free coating solution, (2) coating a base with the coating solution, (3) drying the coated base, and (4) calcining the coated base.

Formation of calcium phosphate coating film and production of substitute

A biocompatible implant material is disclosed comprising (i) particles connected each other and (ii) vacant spaces comprising three-dimensionally interconnected pores present among the particles, wherein the particles have an average size of 10 to 800 .mu.m and the pores have a size of 2 to 800 .mu.m, and the process for producing the biocompatible implant material which comprises granulating a raw powder having an average particle size of 5 .mu.m or smaller to give raw granules having an average particle size of 10 to 800 .mu.m, mixing the raw granules with a combustible substance having an average particle size of 2 to 1,600 .mu.m, pressing the mixture into a shape at a pressure of 1 to 100 kg/cm.sup.2, and then firing the shape.

Process for producing biocompatible implant material by firing a mixture

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Komaki, Japan

Katsuya Yamagiwa