Other

Sumitomo Electric Industries, Limited

Yoshida Kogyo K.k.

Osaka University

I. Sumitomo Electric Industries, Ltd.

Yoshinari Miyamoto

Mitsue Koizumi

Osamu Yamada

Akira Yamakawa

Osamu Komura

Eiji Kamijo

Masaaki Honda

Hirohiko Nakata

Hideki Moriguchi

Toshio Teramoto

Ichiro Matsubara

Hiroshi Yamashita

Hiroyuki Takemura

Kiyotaka Matsuura

Manshi Ooyanagi

Kimiaki Tanihata

A metallic base material is covered with a coating layer of intermetallic compound, or a plurality of metallic base materials are welded to each other with an intermetallic compound, with reduced energy consumption within a short period of time. First metallic substance in powdery form is piled up on metallic base material Second metallic substance in molten form is delivered onto piling layer of the first substance. Thus, under the control of reaction initiation temperature, coating layer (or building up coating layer) of intermetallic compound having a thickness of hundreds of microns (&mgr;m) to millimeters (mm) is formed on the base material by the self-exothermic reaction between the first substance and the second substance. This method is also useful in the welding of a plurality of metallic base materials to each other with an intermetallic compound. The first substance can be constituted of, for example, Ni, Co or Fe. The second substance can be constituted of, for example, Al or Ti. Each base material may be constituted of a metal common with or homologous to the first substance or second substance. The first substance and the second substance can be used in powdery form or molten form, provided that at least one thereof is used in molten form. The first substance may contain a ceramic for imparting reinforcement.

Coating method by intermetallic compound

A coated diamond which is dense and excellent in adherence and enables diamond to exhibit its superior characteristics, a manufacturing method and a composite material of the coated diamond are achieved. The coated diamond includes a diamond ( ) and an SiC film ( ) coating the diamond ( ). The SiC mentioned above is substantially formed of &bgr;-SiC and a value of ratio I (220)/I (111) is at least 0.38 and at most 0.55, I (220) representing peak intensity of Miller index (220) of SiC and I (111) representing peak intensity of Miller index (111) thereof.

Coated diamond, manufacturing method and composite material thereof

Process for preparing NbN superconducting material, characterized in that a bulk Nb is placed in powder including at least one metal which can be nitriding-burned, and then the powder is heated to be nitriding-burned in pressurized N.sub.2 atmosphere so that the bulk Nb is nitrided by the nitriding-burning of the powder.

Process for preparing NbN superconducting material

A high strength Si.sub.3 N.sub.4 composite composed of a sintered body consisting mainly of Si.sub.3 N.sub.4 in which SiC whiskers with a small aspect ratio, preferably an average aspect ratio of 15 to 100, is contained in the sintered body and thereby a considerable improvements can be obtained in the mechanical properties, such as strength, toughness and mechanical shock resistance. The composite is produced by mixing the SiC whiskers with Si.sub.3 N.sub.4 powder and then sintering the resulting mixture by a hot isostatic pressing without using a sintering aid.

High strength Si.sub.3 N.sub.4 composite containing SiC whiskers and

The present invention relates to a pressure self-combustion sintering method for obtaining a ceramic sintered body. Conventionally, in order to sinter ceramics by the pressure self-combustion sintering method, a mixture comprising metallic elements and non-metallic elements has been inserted into an airtight vessel and then a filament formed of W, Mo and the like as a heat source for starting a reaction has been placed within said airtight vessel followed by heating by adding energy to this heat source from outside of the airtight vessel and applying an isostatic pressure to the mixture comprising metallic elements and non-metallic elements to start a synthetic reaction of ceramics from one end of said mixture, thereby carrying out a chain synthetic sintering of ceramics by a reaction heat. However, this method requires drawing a power supply lead wire formed of a filament made of W, Mo and the like out of the airtight vessel for the filament formed of W, Mo and the like placed within the airtight vessel while maintaining a airtightness. It has been said that this is remarkably difficult industrially. Accordingly, the pressure self-combustion sintering method has never been practically used industrially. The present invention was achieved by finding that the problems of the conventional method can be solved by covering an exterior of the airtight vessel, into which the mixture comprising metallic elements and non-metallic elements is inserted, with the mixture comprising metallic elements and non-metallic elements in place of using the filament formed of W, Mo and the like as the heat source, that is ignition agent.

Pressure self-combustion sintering method

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

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Hyogo, Japan

Yoshinari Miyamoto