Sumitomo Chemical Company, Limited

Sumitomo Aluminum Smelting Company, Limited

Tadanori Hashimoto

Koichi Yamada

Kazuhiko Nakano

Norio Matsuda

Akiko Nakazono

Kazuo Horinouchi

Hiroshi Yoshitake

Masaaki Hama

Shigenao Hata

Hiroyuki Yokoyama

Osamu Kobayashi

Yoshinori Furumi

A method for producing .alpha.-form silicon nitride having a central particle diameter of 0.3 to 1.0 .mu.m (.alpha.-Si.sub.3 N.sub.4) of high-grade and fine powder for its sintered body excellent in heat-stability and mechanical strength which comprises heat-treating at 1,450.degree.-1,550.degree. C., in an atmosphere containing nitrogen, a mixture prepared by adding one of additives:

Method for producing .alpha.-form silicon nitride

A method for producing an inorganic sintered body, comprising the steps of:

Method for producing an inorganic sintered body

A composition for forming a transparent conductive film obtained by mixing an organic solution comprising an indium salt of inorganic acid and a tin salt of an inorganic acid with a non-aqueous silica sol. The composition of the present invention shows excellent stability with a lapse of time and good wettability to a substrate plate. A transparent conductive film obtained shows a strong adhesion strength to a substrate plate and has a two-layered structure.

Composition for forming a transparent conductive film

An indium tin oxide sol composition comprising about 0.5 to about 30% by weight of indium oxide, tin oxide in an amount of about 0.5 to about 30% by weight, as converted to a basis of tin, based on indium in the indium oxide, and a dispersing agent, which sol composition is obtained by contacting a solution of an indium salt of an inorganic acid containing a tin salt of an inorganic acid with an ion-exchange resin is disclosed. The indium tin oxide sol composition has a high purity and forms an excellent transparent conductive film.

Indium tin oxide sol composition

When an abrasive having an oleophilic surface intended for use in magnetic recording media, said abrasive being obtained by subjecting an inorganic powder material having a Mohs hardness of 5 or above and an average particle size of 2 .mu.m or below to a wet contact treatment with an aqueous solution or an organic solvent solution containing a dispersing agent having an oleophilic group and drying the treated powder material, is used together with a magnetic powder material in the magnetic recording layer of a magnetic recording medium, the wear of the magnetic head can be prevented and the still characteristics of the recording medium is improved.

Abrasive used in magnetic recording medium and production thereof

A method for producing a high-grade fine powder of .alpha.-form silicon nitride (.alpha.-Si.sub.3 N.sub.4) for use as sintered bodies excellent in heat-stability and mechanical strength which comprises heat-treating, in an atmosphere containing nitrogen, a mixture prepared by adding additive:

Method for producing .alpha.-form silicon nitride fine powders

An electrode for aluminum reduction cells wherein an electrode base, at least in that portion which is brought into contact with a molten salt bath, is coated with a composition comprising at least 50% by weight of electronic conductive oxide ceramics, or said portion of the electrode is made of said composition.

Electrodes for aluminum reduction cells

An electrode for aluminum reduction cells wherein an electrode base at least in its portion that is brought into contact with a molten salt bath is coated with a composition comprising at least 50% by weight of electronic conductive oxide ceramics, or said portion of the electrode is made of said composition.

Aluminum production method with electrodes for aluminum reduction cells

An inorganic composition which is capable of forming a coating film or adherent layer excellent in water resistance, weatherability, heat resistance, chemical resistance, adhesion, surface smoothness, hardness and gloss and which consists essentially of (A) a calcined borate-type mixture obtained by calcining at a temperature of about 300.degree. to about 1,500.degree. C a mixture comprising (i)(a) a borate of a metallic element of Groups II to VIII of the Periodic Table or (i)(b) at least one boric acid compound selected from the group consisting of boric acid and boron oxide and at least one phosphoric acid compound selected from the group consisting of phosphoric acid, phosphorus pentoxide, and metal phosphates and (ii) at least one polyvalent metal compound selected from the group consisting of polyvalent metal oxides, hydroxides, carbonates, phosphates, silicates, sulfates, and nitrates, and (B) a water-soluble silicate.

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Osaka, Japan

Tadanori Hashimoto