Hitachi, Ltd.

Yasuo Matsushita

Kousuke Nakamura

Mitsuru Ura

Yukio Takeda

Tokio Ohkoshi

Ken Takahashi

Satoru Ogihara

Kunihiro Maeda

Seiichi Yamada

Tadamichi Asai

Tetuo Kosugi

Ryutarou Jimbou

Yukio Takahashi

Satoshi Shimada

Kazuji Yamada

Fumiyuki Kobayashi

Yoshiyuki Yasutomi

Hiromitsu Nagae

Koji Harada

Michitaka Shimazoe

Tokio Okoshi

Composite ceramic materials and a method of the same are disclosed, in which a ceramic material mainly containing silicon nitride, and at least one compound selected from a group consisting of nitrides, carbides, borides, silicides, oxides and oxynitrides of elements belonging to IIIa, IIIb, IVa, IBb, Va, VIa and VIII are combined to form a sintered body, and particles and whiskers of the ceramic material and compound are interlocked with each other and fixed so that the sintered body has a porosity of 5 to 30%. In the above composite ceramics, the particle of the compound are coupled with each other through the whisker or particle of the ceramic material. Accordingly, the composite ceramics are small in charge rate of size due to sintering, and are excellent in tenacity, heat resisting property and thermal shock resisting property. Further, the resistivity of the sintered body can be varied by changing the mixture ratio of ceramic material and compound.

Composite ceramics and method of making the same

A semiconductor device with a semiconductor element encased in a hollow ceramic package. The portion of the package at which the semiconductor element is disposed is formed from SiC admixed with Be or a compound of Be.

Ceramic packaged semiconductor device

A semi-conductor device comprising sintered aluminum nitride having a high thermal conductivity, which comprises at least 65% by weight of aluminum nitride, and at least one of beryllium, a beryllium compound, lithium and a lithium compound.

Sintered aluminum nitride semi-conductor device

An ignition distributor for an internal combustion engine with reduced electric discharge energy and suppressed radio noise generation comprises a rotor electrode capable of rotary motion and a plurality of stationary electrodes arranged substantially in a circle around the rotor electrode through an electric discharge clearance therebetween, where the rotor electrode is made of a sintered mixture comprising zirconium oxide and an electroconductive inorganic compound having a specific resistance of not more than 10.sup.6 .OMEGA.cm as main components. The sintered mixture can be ZrO.sub.2 and an oxide selected from ZnO, NiO and CoO; or ZrO.sub.2, aluminum oxide and an oxide selected from ZnO, CoO, Al.sub.2 TiO.sub.5 and SrTiO.sub.3 or a carbide selected from ZrC, TiC and TaC.

Ignition distributor for internal combustion engine

Disclosed are semiconductor devices in which an electrical insulating substrate is made of a sintered silicon carbide body having thermal conductivity of at least 0.4 cal/cm.multidot.sec.multidot..degree.C. at 25.degree. C., electrical resistivity of at least 10.sup.7 ohm.multidot.cm at 25.degree. C. and coefficient of thermal expansion of 3.3.about.4.times.10.sup.-6 /.degree.C. at 25.degree. C. to 300.degree. C.

Semiconductor device having electrically insulating substrate of SiC

An ignition distributor for an internal combustion engine with reduced electric discharge energy and suppressed radio noise generation comprises a rotor electrode capable of rotary motion and a plurality of stationary electrodes arranged substantially in a circle around the rotor electrode through an electric discharge clearance therebetween, where the rotor electrode is a sintered mixture comprising an aluminum compound and/or a boron compound and silicon carbide and having a specific resistance of 10 to 10.sup.6 .OMEGA.cm at room temperature.

An electrically conductive sintered ceramics of the present invention comprises, as the main ingredients thereof, (a) silicon carbide, (b) an inorganic compound which exhibits a positive resistance-temperature coefficient, and preferably (c) a sintering assistant. The electrically conductive sintered ceramics obtained exhibits a positive resistance-temperature coefficient as a whole. A ceramic heater of the invention makes use of the electrically conductive sintered ceramics in an electrically conductive portion thereof. A sintered product which exhibits a positive resistance-temperature coefficient helps to prevent the occurrence of thermal runaway or thermal destruction.

Electrically conductive sintered ceramics and ceramic heaters

Sintered aluminum nitride having a high thermal conductivity, which comprises at least 65% by weight of aluminum nitride, and at least one of beryllium, a beryllium compound, lithium and a lithium compound, and a semi-conductor device using the same.

Sintered aluminum nitride and semi-conductor device using the same

Electroconductive ceramic materials with high density, high mechanical strength, high endurance to repeated current supply and excellent thermal shock resistance can be obtained by mixing 5 to 70 parts by weight of Al.sub.2 O.sub.3 or alumina ceramic materials containing 95% by weight or more of Al.sub.2 O.sub.3 and 30 to 95 parts by weight of at least one electroconductive material selected from of ZrB.sub.2, ZrC, ZrN, ZrSi.sub.2, TaB.sub.2, TaC, TaN, TaSi.sub.2, TiB.sub.2, TiC, TiN, Mo.sub.2 B.sub.5 and MoSi.sub.2 adding a molding binder, molding the mixture and sintering the molded mixture. The electroconductive ceramic is usable for heaters, glow plug heaters, electrical gas ignitors, kerosine gasifying burners, and electrodes or conductors for water processing or dialysis.

Electroconductive ceramics

A semiconductor device with a semiconductor element encased in a hollow ceramic package. The portion of the package at which the semiconductor element is disposed is formed from a SiC-based substrate containing Be or a compound of Be with a thin SiO.sub.2 layer being capable of reacting with glass provided thereon and with a glass layer or a thin film circuit on the SiO.sub.2 layer.

A high-temperature thermistor comprising, a polycrystalline sintered body consisting essentially of 0.1-8 weight percents of at least one kind selected from the group consisting of Be, BeO, Be.sub.2 C, B, BN, B.sub.2 O.sub.3 and B.sub.4 C which weight percents are calculated as the amount of only Be or B single substance from net amount, the balance SiC, and the inevitable impurities having not more than 2 weight percents of SiO.sub.2, not more than 0.1 weight percent of Al, not more than 0.2 weight percents of Fe, not more than 1 weight percent of Si, and not more than 0.4 weights percents of free carbon, a pair of electrode provided on the surfaces of the sintered body, and lead wires each connected to the respective electrodes, and a method of producing same.

High temperature thermistor

From 0.1 to 3.5% by weight of beryllium oxide powder, calculated as beryllium, is added to silicon carbide powder containing up to 0.1% by weight of aluminum, up to 0.1% by weight of boron and up to 0.4% by weight of free carbon, and the mixed powder is pressure-molded. The resulting molded article is heated to a temperature of 1,850.degree. C. to 2,500.degree. C. till there is obtained a sintered body having at least 90% relative density of silicon carbide. Thus, the sintered body having thermal conductivity of at least 0.4 cal/cm.sec..degree. C. at 25.degree. C., electrical resistivity of at least 10.sup.7 Ohm.cm at 25.degree. C. and coefficient of thermal expansion of 3.3.about.4.times.10.sup.-6 /.degree.C. at 25.degree. C. to 300.degree. C. can be obtained.

Electrically insulating substrate and a method of making such a substrate

A semiconductor pressure transducer includes a monocrystalline semiconductor diaphragm, the outer edges of which are fixed. When subjected to pressure, the transducer produces radial strains of opposite polarity in a central portion thereof and a portion surrounding the central portion close to the edge of the strain inducing region. The diaphragm contains a plurality of elongated resistances formed of semiconductor material of the same conductivity type which are electrically isolated from the diaphragm, per se. Resistances of an individual set which lie in proximity to one another are combined in the form of a bridge. The longitudinal direction of resistances forming one set of opposing arms of the bridge extend along axes of the same crystal system as the longitudinal direction of the elongated resistances forming the other set of opposing arms of the bridge. However, the longitudinal directions of the separate sets of resistances forming the opposing arms of the bridge lie in directions so that they do not orthogonally intersect each other.

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Hitachi, Japan

Yasuo Matsushita