POLISHING MATERIAL, POLISHING COMPOSITION, AND POLISHING METHOD

PROBLEM TO BE SOLVED: To provide a polishing material capable of polishing surfaces of an alloy and a metal oxide with a sufficient polishing speed and obtaining a high-quality mirror surface; a polishing composition; and a polishing method.SOLUTION: A polishing material contains alumina which has a rate of transformation to alpha-alumina of 80% or more and 50% particle diameter in cumulative particle diameter distribution based on the volume of 0.15 μm or more and 0.35 μm or less. A polishing composition contains the polishing material and has a pH of 7 or less. The polishing material and the polishing composition are used in polishing the polishing object containing at least one of an alloy and a metal oxide.SELECTED DRAWING: None 【課題】合金や金属酸化物の表面を十分な研磨速度で研磨可能であり高品位な鏡面を得ることが可能な研磨材、研磨用組成物、及び研磨方法を提供する。【解決手段】研磨材は、α化率が８０％以上で且つ体積基準の積算粒子径分布における５０％粒子径が０．１５μｍ以上０．３５μｍ以下であるアルミナを含有する。研磨用組成物は、この研磨材を含有し、ｐＨが７以下である。この研磨材及び研磨用組成物は、合金及び金属酸化物の少なくとも一方を含有する研磨対象物の研磨に使用される。【選択図】なし