ALUMINA POWDER, PROCESS FOR PRODUCING THE SAME AND POLISHING COMPOSITION

摘要

Production of an alumina powder characterized by having a single or multiple crystal structure selected from the group consisting of gamma , delta and theta -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 alpha -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 bohemite structure and having a length of one side of 10 to 50 nm. Preparation of a polishing composition comprising the alumina powder, water and a polishing accelerator.