Patent ID: 8226841

Claim:
A method of chemically-mechanically polishing a substrate comprising: (i) contacting a substrate with a polishing pad and a chemical-mechanical polishing composition comprising: (a) alpha alumina, (b) fumed alumina, (c) silica, (d) an oxidizing agent that oxidizes nickel-phosphorous, (e) about 0.1 wt. % to about 2 wt. % of oxalic acid, (f) about 0.1 wt % to 0.75 wt. % tartaric acid, (g) a nonionic surfactant, (h) optionally, a biocide, and (i) water, wherein the polishing composition has a pH of about 2 to about 4, (ii) moving the polishing pad relative to the substrate with the chemical-mechanical polishing composition therebetween, and (iii) abrading at least a portion of the substrate to polish the substrate, wherein the substrate comprises a nickel-phosphorous-coated aluminum disk.