Sumitomo Chemical Company, Limited

Hideaki Murakami

Hidekimi Kadokura

Hiroshi Umezaki

Kazuhiko Nakano

Norio Matsuda

Mitsutoshi Murase

Toshiyuki Mizoe

An aluminum nitride powder obtained by firing and reacting a mixture of alumina and carbon in a nitrogen-containing atmosphere is disclosed, the aluminum nitride powder having an oxygen content of not more than 2.0% by weight, an iron content of not more than 20 ppm, a silicon content of not more than 100 ppm, and a titanium content of not more than 20 ppm and having has a tapped density of at least 1.0 g/cm.sup.3. An aluminum nitride powder containing from 0.01% to 10% by weight of a sintering aid is also disclosed, the aluminum nitride powder having an oleophilic surface and having a tapped density of at least 1.0 g/cm.sup.3. The aluminum nitride powder of the present invention has excellent moldability, has a high tapped density, is less in formation of coagulated particles, and has a sharp particle size distribution.

Aluminum nitride powder and process for preparation of the same

In a furnace which allows a feed powder or granules in a stack of trays on a base plate to be reacted with a reactive gas, the improvement wherein each of the trays has a cutout or an opening providing a passage for the reactive gas or the produced gas both at the top of one side wall and in the bottom wall to the opposite side of the tray, the base plate having an opening through which the reactive gas is introduced or the produced gas is discharged.

Furnace structure for ceramic powder production

When an abrasive having an oleophilic surface used in a magnetic recording medium obtained by subjecting an inorganic powder having a Mohs hardness of 5 or above and an average particle size of 2 .mu.m across or below to a dry contact treatment with a dispersing agent having an oleophilic group under grinding conditions giving an impact value of 1G or greater is used in combination with a magnetic powder as a magnetic recording layer of magnetic recording medium, the wear at a magnetic head can be prevented and still characteristics can be improved.

Abrasive, production thereof and use thereof in magnetic recording medium

A method for producing .gamma.-form lithium aluminate powders usable as a material for an electrolyte tile of molten carbonate fuel cells which comprises mixing aluminum alkoxide with one member selected from the group consisting of the lithium salts of inorganic and organic acids, lithium hydroxide and lithium oxide in the presence of a non-aqueous solvent, carrying out reaction with addition of water of 1.5 to 20 moles (including water of crystallization contained in the lithium compound) based on 1 mole of aluminum alkoxide with stirring, and removing the solvent to obtain a solid matter which is then calcined at a temperature in a range of from 650.degree. C. to 1000.degree. C.

Method for producing lithium aluminate powders

A magnetic recording medium comprising a substrate and a magnetic layer formed on the substrate and comprising an inorganic powder having an average primary particle size of 0.35 .mu.m or less, an angle of repose of 40.degree. or more and a Mors hardness of 5 or more as a reinforcing material, and a magnetic powder, is excellent in wear resistance and durability of the magnetic layer and improves wear and injury of a magnetic head.

Magnetic recording medium

When an abrasive having an oleophilic surface used in a magnetic recording medium obtained by subjecting an inorganic powder having a Mohs hardness of 5 or above and an average particle size of 2 .mu.m across or below to a dry contact treatment with a dispersing agent having an oleophilic group under grinding conditions giving an impact value of 1 G or greater is used in combination with a magnetic powder as a magnetic recording layer of magnetic recording medium, the wear at a magnetic head can be prevented and still characteristics can be improved.

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Niihama, Japan

Hideaki Murakami