Sumitomo Electric Industries, Limited

Other

Agency of Industrial Science and Technology

Rikagaku Kenkyusho

Director General Agency of Industrial Science and Technology

I. Sumitomo Electric Industries, Ltd.

Eiji Kamijo

Matsuo Higuchi

Tatsuya Nishimoto

Akira Yamakawa

Osamu Komura

Masaaki Honda

Osamu Yamada

Mitsue Koizumi

Yoshinari Miyamoto

Fumio Ono

Ikuji Uemura

Masaya Miyake

Hisao Takeuchi

Yoshinobu Takeda

Koichi Okita

Kazuhito Murakami

Shohei Isomura

Yoji Kawami

Noboru Wakabayashi

Ryohei Nakane

Eiichi Torigai

Katsuhito Tani

Katsuto Tani

The present invention relates to a method of sintering ceramics and ceramics obtained by said method. According to the present invention, the synthesis and sintering of ceramics can be simultaneously carried out by utilizing the reaction heat generated when at least one metallic element selected from metallic elements of IIb, IVb, Vb and VIb groups of the Periodic Table is combined with at least one nonmetallic element such as B, C N and Si without heat or by preliminarily heating the ceramics at temperatures remarkably lower than the usual sintering temperature ceramics thus-produced are superior in abrasion resistance and corrosion resistance. Furthermore, according to the present invention, particles of the same kind of metal as that used in constructing the ceramics comprising the above described metallic elements and nonmetallic elements are dispersed in a matric comprising said ceramics to obtain metal dispersed reinforced ceramics in which both the matrix and the metallic particles are strongly and chemically bonded to each other. According to the latter procedure, ceramic materials having high temperature characteristics, high corrosion resistance and high abrasion resistance, as well as high toughness and high impact resistance can be obtained.

Method of sintering ceramics and metal dispersed reinforced ceramics

The present invention relates to a method of sintering ceramics and ceramics obtained by said method. According to the present invention, the synthesis and sintering of ceramics can be simultaneously carried out by utilizing the reaction heat generated when at least one metallic element selected from metallic elements of IIIb, IVa, Vb and VIb groups of the Periodic Table is combined with at least one nonmetallic element such as B, C, N and Si without heat or by preliminarily heating the ceramics at temperatures remarkably lower than the usual sintering temperature ceramics, thus-produced are superior in abrasion resistance and corrosion resistance. Furthermore, according to the present invention, particles of the same kind of metal as that used in constructing the ceramics comprising the above described metallic elements and nonmetallic elements are dispersed in a matrix comprising said ceramics to obtain metal dispersed reinforced ceramics in which both the matrix and the metallic particles are strongly and chemically bonded to each other. According to the latter procedure ceramic materials having high temperature characteristics, high corrosion resistance and high abrasion resistance, as well as high toughness and high impact resistance can be obtained.

Dispersed reinforced ceramics

The present invention relates to a method of hot rolling copper or copper alloys such as copper wires and coppr plates. The present invention has succeeded in remarkably prolonging useful life of the tools used for hot rolling, and improving the surface quality of the rolled products by replacing the conventional methods of hot rolling copper using tools made of cemented carbide, die steel, high-speed steel, etc. by a method using tolls made essentially of Si.sub.3 N.sub.4. Si.sub.3 N.sub.4 tools used in the present invention contain at least one kind of sintering aid selected from the group consisting of Al.sub.2 O.sub.3, AlN, MgO, Y.sub.2 O.sub.3 and ZrO.sub.2, have a sintering density of 90% or more, Rockwell hardness of 88 or more and an average particle diameter of 2.mu. or less, and contain .beta.-type Si.sub.3 N.sub.4 as a main ingredient.

Method of hot rolling copper

A novel method of hot rolling iron and iron alloy rods, using a hot rolling tool comprising .beta.-Si.sub.3 N.sub.4 and a sintering aid selected from the group consisting of Al.sub.2 O.sub.3, AlN, MgO, Y.sub.2 O.sub.3 and ZrO.sub.2, and having a sintered density of 90% or more, Rockwell hardness of 88 or more and a mean particle size of 2.mu. or less.

Method of hot rolling for iron and iron alloy rods

A method for manufacturing a fiber reinforced silicon carbide or silicon nitride ceramic sintered body having silicon carbide or silicon nitride ceramic whiskers dispersed therein, which method involves mixing together silicon carbide or silicon nitride ceramic powder, whisker formation agents made up of at least one material selected from metal Si or an inorganic compound containing Si, an organic containing Si, amorphous silicon ceramic powder or a mixture of SiO.sub.2 and carbon, or Si, sintering additives, and a whisker accelerating amount of a whisker formation accelerator selected from Fe, Ni, Co, Cr, V, Ti, Ta, W or Mo; molding the mixture into a predetermined shape; heat treating the molded body at a temperature of 1300.degree. C. to 1750.degree. C. to produce silicon carbide or silicon nitride whiskers in the molded body and thereafter densifying and sintering the molded body at sintering temperatures in a non-oxidizing atmosphere. The silicon carbide and silicon nitride ceramics produced by said method have excellent heat-resistance characteristics and excellent impact and corrosion resistance, thus making these ceramics eminently suitable for structural materials where these properties are required.

Manufacturing method for fiber reinforced silicon ceramics sintered body

Less dispersion and more homogenized ceramics are produced by sintering ceramic materials, in particular, containing silicon nitride or silicon carbide as a predominant component with other assistants or additives, machining the surface of the resulting sintered compact and then subjecting the sintered compact to a heat treatment for homogenizing in a non-oxidizing atmosphere such as nitrogen or argon gas at a temperature of from the mass-transfer temperature at which the mass-transfer takes place in the interior of the ceramics to blunt the fine point of a crack to the sintering temperature of the ceramics.

Process for the production of ceramics

An electrically-conductive sintered compact of silicon nitride which is machinable by electrical discharge machining and a process to produce the same. TiN and/or TiC powder is added to a powder of silicon nitride in an amount 15-40% by volume to act as a conductivity-supplying agent while 0.01-3.0% by volume MgO and/or Al.sub.2 O.sub.3 powder is added as a sintering assistant. The mixed powders are then preformed in a desired shape and sintered in a nonoxidizing environment at 1,600.degree. C.-2,000.degree. C. to obtain a compact of silicon-nitride machinable by electrical discharge machining due to its electrical conductivity being at least 1 S.multidot.cm.sup.-1.

Electrically-conductive sintered compact of silicon nitride machinable

A novel thin film magnetic head is provided characterized by the use of a new substrate material excellent in mechanical property as well as machinability. This substrate is composed of a ceramic compact comprising 4 to 45% by volume of Component A, 55 to 96% by volume of Component B and at most 3% by volume of unavoidable impurities:

Thin film magnetic heads and substrates therefore

A ceramic compact having a high transverse rupture strength is provided by a low cost sintering method. This ceramic compact comprises 55 to 96% by volume of a first component, 4 to 45% by volume of a second component and at most 3% by volume of unavoidable impurities:

Ceramic compacts

A process and an apparatus for manufacturing a fine powder of metals or ceramics are proposed in which a mixed gas of volatile metal compound and/or evaporated metal and a reaction gas is reacted in a discharged state while heating by laser beam.

Process and apparatus for manufacturing fine powder

The invention relates to an aqueous electrolytic cathode and/or anode in which an aqueous solution of alkaline metal hydroxide is used or an active nickel or nickel alloy electrode having greater stability and smaller overvoltage under the condition of high current density for use in electrolysis of aqueous solution of alkaline metal halide, and the method for producing the same. Electrode material consisting of nickel or nickel alloy or electrode material of multiple layers comprising said electrode material coated with nickel or nickel alloy powder is forcibly subjected to oxidization and reduction treatments in repetition under a selected treatment temperature and atmosphere so that the surface area is expanded by the production of surface openings, thereby enabling to obtain an electrode having the said high properties.

Electrode and the method for producing the same

A process for continuous production of porous metal in a tape form is disclosed which comprises the steps of treating a non-conductive porous tape to give its skelton surface electrical conductivity and then moving the porous tape in an electrolytic bath in close contact with a moving cathode immersed in said bath to electroplate it to a predetermined thickness.

Process for continuous production of porous metal

A catalyst for concentrating hydrogen isotopes for use in performing hydrogen isotopes exchange between gaseous hydrogen and liquid water, the catalyst comprising a support of porous polytetrafluoroethylene having a total specific surface area of 2 to 80 m.sup.2 /g as a result of mixing therewith 0.5 to 15% by weight of fluorocarbon or a porous styrene polymer or styrene/divinylbenzene copolymer having a specific surface area of at least 150 m.sup.2 /g, and deposited on the support particles of at least one element selected from Group VIII of the Periodic Table. A method for producing a support of porous polytetrafluoroethylene for such catalyst is also disclosed.

Catalyst for concentrating hydrogen isotopes and process for producing a

A method for producing a tubular multi-layered porous barrier comprising the step of depositing fine powder onto at least one of the inner and outer surfaces of a sintered tubular porous support member in a layer of uniform thickness to form a fine powder layer and pressurizing said powder layer against said support member to form a porous barrier layer on the support member.

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Itami, Japan

Eiji Kamijo