A method and system for planarizing or polishing a substrate, particularly a memory or rigid disk, are provided. The method comprises abrading at least a portion of the surface with a polishing system comprising (i) a polishing composition comprising water, an oxidizing agent, and about 0.04 M or higher phosphate ion or phosphonate ion, and (ii) abrasive material. The present invention also provides a system for planarizing or polishing a substrate comprising (i) a polishing composition comprising water, an oxidizing agent, and about 0.04 M or higher phosphate ion or phosphonate ion, and (ii) silica particles.