Kyocera Corporation

Katsushi Sakaue

Shigenobu Nakamura

Takeshi Okamura

Masaki Terazono

Mitsuo Kondo

Masahiro Sato

Takero Fukudome

Takaaki Hira

Katsura Hayashi

Yasushi Migita

Hirotaka Tsuyoshi

Susumu Ono

Hitoshi Atari

Shigenobu Nakaumra

Ryuusuke Tsuyoshi, Legal Representative

Shoji Kosaka

Junji Ohe

Ichio Kiyofuji

Naohito Higashi

A multi-layer piezoelectric element having high durability which allows it to increase the amount of displacement of a piezoelectric actuator under high voltage and high pressure and does not undergo a change in the amount of displacement during continuous operation in a high electric field and under a high pressure over a long time period is provided. The multi-layer piezoelectric element comprises a stack of at least one piezoelectric layer and a plurality of internal electrodes consisting of first and second internal electrodes placed one on another, a first external electrode formed on a first side face of the stack and connected to the first internal electrode and a second external electrode formed on a second side face of the stack and connected to the second internal electrode, wherein the bonding strength between the piezoelectric layer and the internal electrode is weaker than the bending strength of the piezoelectric layer.

Multi-layer piezoelectric element and method for manufacturing the same

To provide a multi-layer piezoelectric device having excellent durability in which the amount of displacement does not change even when the piezoelectric actuator is subjected to continuous operation over a long period of time under a high voltage and a high pressure, the multi-layer piezoelectric device comprises a stack formed by stacking piezoelectric layers and internal electrodes alternately one on another and external electrodes formed on a first side face and on a second side face of the stack, wherein one of the adjacent internal electrodes is connected to the external electrode formed on the first side face and the other internal electrode is connected to the external electrode formed on the second side face, while content of alkali metal in a range from 5 ppm to 300 ppm is contained.

Multi-layer piezoelectric device

Multi-layer piezoelectric element

A laminated piezoelectric device obtained by alternately laminating the piezoelectric layers containing Pb and the conducting layers containing palladium as a conducting component, wherein the piezoelectric layer formed between the two conducting layers has layer regions where Pb and Pd are mixed together in the interfacial portions thereof relative to the conducting layers, the layer regions having a thickness of not larger than 3% of the thickness of the piezoelectric layer. The laminated piezoelectric device is formed by co-firing the Pb-containing piezoelectric layers and the palladium (Pd)-containing layers, the piezoelectric layers therein having a large insulation resistance and good piezoelectric characteristics.

Laminated piezoelectric device

In order to provide a multi-layer electronic component in which the occurrence of delamination between the ceramic layer and the internal electrode is restricted and a method for manufacturing the same, the multi-layer electronic component of the present invention comprises a stack formed by stacking piezoelectric layers and internal electrodes one on another alternately and a pair of external electrodes formed on two opposing side faces of the stack, wherein the internal electrode consists of a first internal electrode connected to the external electrode formed on one of the two side faces and a second internal electrode located between the first internal electrode and connected to the external electrode formed on the other one of the two side faces, and wherein the internal electrodes and the piezoelectric layers are faced in proximity so that a space between them is 2 &#x3bc;m or less over an area occupying 50% or more of the active region where the first internal electrode and the second internal electrode oppose each other.

Multi-layer electronic component and method for manufacturing the same, multi-layer piezoelectric element

A multi-layer piezoelectric element having excellent durability in which the amount of displacement does not change even after subjecting to continuous operation over a long period of time under a high voltage and a high pressure is provided. The multi-layer piezoelectric element comprises a stack formed by stacking piezoelectric layers and internal electrodes alternately one on another and external electrodes the proportion of silver contained in electrically conductive material of the internal electrode near the junction with the external electrode is higher than the proportion of silver contained in electrically conductive material of the internal electrode located inside of the stack.

Electrostatic chuck

A sintered product of silicon nitride has a crystal phase of RE,Si,N,O,or RE,AlSi,O,N,(RE is an element of the Group 3a of periodic table) precipitated on the grain boundaries of the silicon nitride crystal phase, and exhibits a high strength over a wide temperature region of from normal temperature to a temperature of as high as 1000&deg; C., as well as excellent oxidation resistance and static fatigue property. The sintered product of silicon nitride is very useful as parts for heat engines, such as parts for engines and parts for gas turbines.

Sintered product of silicon nitride

A silicon nitride sintered body containing a .beta.-silicon nitride crystal phase and further containing at least a rare earth element component and an aluminium component in a grain boundary phase, wherein the intensity ratio (X2/X1) of the Si peak X.sub.2 at 521 cm.sup.-1 to the Si.sub.3 N.sub.4 peak X.sub.1 at 206 cm.sup.-1, as detected by a Raman spectrochemical analysis method, is 0.2 to 3. A very minor amount of Si (elemental silicon), as detected by the Raman spectrochemical analysis method, is precipitated in the sintered body, and by this precipitation of Si, strength and toughness are markedly increased.

Silicon nitride sintered body

The whiskers-reinforced ceramics of the present invention is prepared from alumina powder activated by dry milling, with which Ti-based whiskers are mixed, by molding and sintering said mixture. By the present invention the bending strength of the sintered body can be increased without impairing the effect of improving the fracture toughness which is imparted by the incorporation of Ti-based whiskers, since the particle size of alumina crystal in the sintered body can be controlled to 3 microns or less.

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Kirishima, Japan

Katsushi Sakaue