Ngk Insulators, Inc.

Ritsu Tanaka

Hirofumi Yamaguchi

Yukinobu Yura

Kazuyuki Kaigawa

Tsutomu Nanataki

Takaaki Koizumi

Hirotake Yamada

Shuichi Ozawa

Tomio Suzuki

Piezoelectric materials having improved electrical properties, and manufacturing methods of the same, are provided. In (Li, Na, K, Bi)(Nb, Ta)Obased piezoelectric materials, the surface microstructures of sintered bodies include microscopic grains having grain diameters of less than 5 &#x3bc;m, intermediate grains having grain diameters of 5 &#x3bc;m or more and less than 15 &#x3bc;m, and coarse grains having grain diameters of 15 &#x3bc;m or more and 100 &#x3bc;m or less.

(Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material and manufacturing method of the same

A piezoelectric/electrostrictive ceramic sintered body has a microstructure in which a matrix phase and an additional material phase having different compositions coexist and the additional material phase is dispersed in the matrix phase. A residual strain ratio of the additional material phase alone is larger than a residual strain ratio of the matrix phase alone. The matrix phase and the additional material phase have a composition in which a Mn compound containing Mn atoms of 0 parts by mole or more and 3 parts by mole or less and a Ba compound containing Ba atoms of 0 parts by mole or more and 1 part by mole or less are contained in a composite of 100 parts by mole represented by a general formula {Li(NaK)}(NbTaSb)O, where a, x, y, z and w satisfy 0.9&#x2266;a&#x2266;1.2, 0.2&#x2266;x&#x2266;0.8, 0.0&#x2266;y&#x2266;0.2, 0&#x2266;z&#x2266;0.5 and 0&#x2266;w&#x2266;0.1, respectively.

Piezoelectric/electrostrictive ceramics sintered body

A (Li, Na, K)(Nb, Ta)O-based piezoelectric/electrostrictive ceramic composition having large electric field-induced distortion at the time of application of a high electric field is provided. A perovskite oxide is synthesized which contains Li (lithium), Na (sodium) and K (potassium) as A-site elements and contains at least Nb (niobium) and Sb (antimony) out of Nb, Ta (tantalum) and Sb as B-site elements, the ratio of the total number of atoms of the A-site elements to the total number of atoms of the B-site elements being larger than 1, and then a Bi (bismuth) compound is added and reacted. The amount of addition of the Bi compound with respect to 100 molar parts of the perovskite oxide is preferably not less than 0.02 molar part nor more than 0.1 molar part in terms of Bi atoms.

Method of manufacturing piezoelectric/electrostrictive ceramic composition

An alkali niobate-based piezoelectric/electrostrictive ceramics sintered body including, as a main crystal phase, a perovskite type oxide containing at least one type of element selected from the group consisting of Li, Na and K as A site constituent elements and at least one type of element selected from the group consisting of Nb and Ta as B site constituent elements. The number of lattice-strained layers of the piezoelectric/electrostrictive ceramics sintered body is preferably small. A diffuse scattering intensity ratio, which is a ratio of an intensity of diffuse scattering by a lattice-strained layer present near a domain wall to a sum of an X-ray diffraction intensity of a first lattice plane and that of a second lattice plane different in interplanar spacing from the first lattice plane due to crystallographic symmetry reduction is preferably 0.5 or lower.

Piezoelectric/electrostrictive ceramics sintered body having a banded structure

A (Li, Na, K)(Nb, Ta)Obased piezoelectric/electrostrictive porcelain composition obtained by adding a slight amount of a Mn compound to a perovskite type oxide containing Li, Na and K as A-site elements and contains at least Nb out of Nb and Ta as B-site elements, where a ratio of a total number of atoms of the A-site elements to a total number of atoms of the B-site elements is not smaller than 1. A composition of the perovskite type oxide as a principal component is represented by a general formula: {Li(NaK)}(NbTa)O. The A/B ratio 'a' preferably satisfies 1&#x3c;a&#x2266;1.05. The Mn compound as an accessory component is desirably added such that the added amount is not more than 3 parts by mol in terms of Mn atom with respect to 100 parts by mol of said perovskite type oxide.

Piezoelectric/electrostrictive porcelain composition and piezoelectric/electrostrictive element

A (Li, Na, K)(Nb, Ta)O-based piezoelectric/electrostrictive ceramic composition having a large field-induced distortion during application of a high electric field is provided. After synthesizing a perovskite oxide containing Li (lithium), Na (sodium) and K (potassium) as A-site elements and containing at least Nb (niobium) out of the Nb and Ta (tantalum) as B-site elements, a ratio of total number of atoms of the A-site elements to total number of atoms of the B-site elements being higher than 1, a Bi (bismuth) compound is added to the perovskite oxide and the perovskite oxide is reacted with the Bi compound. An addition amount of the Bi compound with respect to 100 molar parts of the perovskite oxide is preferably equal to or greater than 0.01 molar part and equal to or smaller than 0.1 molar part in terms of Bi atoms.

Piezoelectric/electrostrictive ceramic composition manufacturing method

A piezoelectric/electrostrictive ceramic sintered body has a microstructure in which a matrix phase and an additional material phase having different compositions coexist and the additional material phase is dispersed in the matrix phase. A residual strain ratio of the additional material phase alone is larger than a residual strain ratio of the matrix phase alone. The matrix phase and the additional material phase have a composition in which a Mn compound containing Mn atoms of 0 parts by mol or more and 3 parts by mol or less and a Sr compound containing Sr atoms of 0 parts by mol or more and 1 part by mol or less are contained in a composite of 100 parts by mol represented by a general formula {Li(NaK)}(NbTaSb)O, where a, x, y, z and w satisfy 0.9&#x2266;a&#x2266;1.2, 0.2&#x2266;x&#x2266;0.8, 0.0&#x2266;y&#x2266;0.2, 0&#x2266;z&#x2266;0.5 and 0&#x2266;w&#x2266;0.1, respectively.

A dielectric device of higher performance is provided. An electron emitter, to which the dielectric device is applied is provided with: an emitter including a dielectric; and an upper electrode and a lower electrode to which drive voltage is applied in order to emit electrons. The emitter is formed by the aerosol deposition method or the sol impregnation method.

Dielectric electron emitter comprising a polycrystalline substance

A piezoelectric/electrostrictive device which exhibits an excellent piezoelectric characteristic and which has only a small dependence on a temperature is provided. The piezoelectric/electrostrictive device includes a piezoelectric/electrostrictive portion made of a piezoelectric ceramic, and electrodes electrically connected to the piezoelectric/electrostrictive portion. The piezoelectric ceramic reversibly transits to a tetragonal phase and an orthorhombic phase at a phase transition point as a boundary. The piezoelectric/electrostrictive portion is formed by a polarization treatment performed under the conditions that a treatment temperature ranges from a first temperature which exceeds the phase transition point of the piezoelectric ceramic to a second temperature which is 50&#xb0; C. higher than the first temperature.

Piezoelectric ceramic and method of manufacturing the same

A piezoelectric/electrostrictive porcelain composition is provided, including at least Nb, Ta, and one or more alkali metal elements, wherein a molar ratio of the Nb, Ta, and alkali metal element is represented by a non-stoichiometric composition ratio.

Piezoelectric/electrostrictive porcelain composition and method of manufacturing the same

A monomorph type piezoelectric/electrostrictive device includes a piezoelectric/electrostrictive body, which is composed of a non-lead based piezoelectric/electrostrictive crystalline body containing at least Nb, Ta, and one or more types of alkali metal element, which has a cubic crystal structure at a temperature higher than the phase transition point and at least any one of tetragonal and orthorhombic crystal structures at a temperature lower than the phase transition point, and which is curved to a large extent by a polarization treatment to take on a curved shape at a temperature lower than the phase transition point without application of a voltage after the polarization treatment. In the polarization treatment, an electric field is increased at a speed of from 0.1 (kV/mm)/sec or more to 5 (kV/mm)/sec or less, with applying the maximum electric field of from 2 kV/mm or more to 1.0 kV/mm or less.

Monomorph type piezoelectric/electrostrictive device and method for manufacturing the same

A dielectric device of higher performance is provided. An electron emitter, to which the dielectric device is applied is provided with: an emitter including a dielectric; and an upper electrode and a lower electrode to which drive voltage is applied in order to emit electrons. The emitter is formed by the aerosol deposition method or the sol impregnation method, and the surface roughness of the upper surface thereof is controlled in the range from 0.1 to 3 in Ra.

Electron emitter comprised of dielectric material mixed with metal

A method and apparatus ( ) are used for manufacturing a wire structure wherein a wire ( ) is three-dimensionally aligned at prescribed pitches. The method comprises the steps of providing one or more frame bodies ( ) which have a prescribed thickness, peripherally of a rotary shaft ( ). By rotating rotary shaft ( ) about a rotation axis thereof, wires ( ) are wound, at prescribed pitches, around frame bodies ( ). Another frame body ( ) is stacked on at least one existing frame body and wire ( ) is wound thereon at prescribed pitches. The above steps are repeated to yield a wire structure having a wire aligned three-dimensionally and accurately at prescribed pitches.

Method and device for three-dimensional arrangement of wire and method of manufacturing conductive material

A process for forming a ceramic thin film on a surface of a ceramic body, including the steps of preparing an annular body from a ceramic green sheet, inserting the ceramic body into the annular body, and firing the thus assembled annular body and ceramic body, whereby the annular body is shrunk and joined to the ceramic body.

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Nagoya, Japan

Ritsu Tanaka