Patent ID: 7553345

Claim:
A polishing composition for a Ni-P plated substrate, comprising: water, an abrasive consisting essentially of alumina, wherein said alumina comprises α-alumina and θ-alumina, an organic acid comprising citric acid, a surfactant comprising diisobutylene-maleic acid copolymer and salts thereof, and a salt of a sulfur-containing inorganic acid comprising ammonium sulfate, wherein said alumina is contained in an amount of from 3 to 25% by weight of the polishing composition, said organic acid is contained in an amount of from 0.1 to 8% by weight of the polishing composition, said surfactant is contained in an amount of from 0.005 to 0.5% by weight of the polishing composition, and said salt of a sulfur-containing inorganic acid is contained in an amount of from 0.05 to 5% by weight of the polishing composition; and wherein said polishing composition has a pH of from 2 to 5.