Nissan Chemical Industries Limited

Riken Corporation

Toshio Kasai

Isao Ota

Tohru Nishimura

Takao Kaga

Kenji Tanimoto

Hitoshi Ohmori

Kiyomi Ema

Nobuhide Itoh

Masayuki Ishii

Toshiaki Uno

Kenichiro Horio

Toshiro Karaki-Doy

Production of an alumina powder characterized by having a single or multiple crystal structure selected from the group consisting of &ggr;, &dgr; and &thgr;-forms, a primary particle size of 10 to 50 nm, a mean secondary particle size of 100 to 500 nm, and a granular primary particle shape, or an alumina powder characterized by having an a-form crystal structure, a primary particle size of 60 to 150 nm, a mean secondary particle size of 200 to 500 nm, and a granular primary particle shape, using as a raw material an alumina hydrate comprising rectangular plate-like primary particles having a boehmite structure and having a length of one side of 10 to 50 nm; and preparation of a polishing composition comprising the alumina powder, water and a polishing accelerator.

Alumina powder, process for producing the same and polishing composition

According to the present invention, a process is provided for producing crystalline ceric oxide particles having a particle diameter of 0.005 to 5 &mgr;m, which comprises the steps of reacting a cerium (III) salt with an alkaline substance in an (OH)/(Ce ) molar ratio of 3 to 30 in an aqueous medium in an inert gas atmosphere to produce a suspension of cerium (III) hydroxide, and blowing oxygen or a gas containing oxygen into the suspension at a temperature of 10 to 95&deg; C. and at an atmospheric pressure.

Polishing abrasive of crystalline ceric oxide particles having surfaces modified with hydroxyl groups

The method disclosed here comprises the steps of (a) mixing metal powder, a resin, abrasive grains, and a solid reducing agent at the normal (room) temperature through the melting point of the reducing agent to form a mixture and (b) molding and baking the mixture at the melting point of the reducing agent through that of the metal powder. The solid reducing agent is a fatty acid, preferably stearic acid having a volume ratio of 5 to 20% with respect to the metal powder. With is, it is possible to make metal-resin bond grindstones that give such high-quality mirror surfaces that have conductivity fit for ELID grinding and are not liable to have chippings or scratches and also have an Rmax value of approximately 3 nm or less.

Metal-resis bond grindstone and method for manufacturing the same

A polishing composition for an aluminum disk includes water, an alumina abrasive agent and a polishing accelerator. The polishing accelerator is preferably basic aluminum nitrate. A process for polishing an aluminum disk using the polishing composition is also provided.

Polishing composition for aluminum disk and polishing process therewith

According to the present invention, a process is provided for producing crystalline ceric oxide particles having a particle diameter of 0.005 to 5 .mu.m, which comprises the steps of reacting a cerium (III) salt with an alkaline substance in an (OH)/(Ce.sup.3+) molar ratio of 3 to 30 in an aqueous medium in an inert gas atmosphere to produce a suspension of cerium (III) hydroxide, and blowing oxygen or a gas containing oxygen into the suspension at a temperature of 10 to 95.degree. C. and at an atmospheric pressure.

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Urawa, Japan

Toshio Kasai