Abstract: The silicon carbide powder is a powder of silicon carbide having an ?-type crystal system, where the number of small corner portions among corner portions on a surface of a primary particle of silicon carbide constituting the powder of silicon carbide is 2.5 or less per one primary particle. The small corner portion is a corner portion, among corner portions present in a contour of the primary particle in a projection image of the primary particle, where twice a curvature radius of the corner portion is 1/5 or less of a Heywood diameter of the projection image of the primary particle.

Abstract: There is provided a polishing composition, containing abrasive grains and an acid represented either by R2—R1—SO3H (wherein R1 is a linear alkylene or hydroxyalkylene group having 1 to 4 carbon atoms, and R2 is a hydroxy group, a carboxy group, or a sulfonic acid group when R1 is the linear alkylene group, or R2 is a carboxy group or a hydroxymethyl group when R1 is the linear hydroxyalkylene group), or by C6H5—R3 (wherein R3 is a sulfonic acid group or a phosphonic acid group). The acid contained in the polishing composition is preferably isethionic acid or benzenesulfonic acid. The polishing composition is mainly used in the application of polishing silicon oxide materials including glass substrates for hard disks, synthetic quartz substrates for photomasks, and low-dielectric-constant films such as silicon dioxide films, BPSG films, PSG films, FSG films, and organosiloxane films of semiconductor devices.

Abstract: Provided is a polishing composition containing an abrasive and water. The abrasive content in the polishing composition is no less than 0.1% by mass. The abrasive contains zirconium oxide particles. The zirconium oxide particles have a specific surface area of from 1 to 15 m2/g. The zirconium oxide particles preferably have a purity of no less than 99% by mass. The polishing composition is used in, for example, polishing a hard and brittle material, such as sapphire, silicon nitride, silicon carbide, silicon oxide, glass, gallium nitride, gallium arsenide, indium arsenide, and indium phosphide.

Abstract: There is provided a polishing composition, containing abrasive grains and an acid represented either by R2—R1—SO3H (wherein R1 is a linear alkylene or hydroxyalkylene group having 1 to 4 carbon atoms, and R2 is a hydroxy group, a carboxy group, or a sulfonic acid group when R1 is the linear alkylene group, or R2 is a carboxy group or a hydroxymethyl group when R1 is the linear hydroxyalkylene group), or by C6H5—R3 (wherein R3 is a sulfonic acid group or a phosphonic acid group). The acid contained in the polishing composition is preferably isethionic acid or benzenesulfonic acid. The polishing composition is mainly used in the application of polishing silicon oxide materials including glass substrates for hard disks, synthetic quartz substrates for photomasks, and low-dielectric-constant films such as silicon dioxide films, BPSG films, PSG films, FSG films, and organosiloxane films of semiconductor devices.