Patent ID: 8827769
Filing Date: 2014-09-09
Classification: B24B

Abstract:
1. A method of producing a substrate for magnetic recording media comprising: a rough polishing step of polishing a surface of a substrate for magnetic recording media using a first grinder while supplying a polishing liquid containing alumina abrasive grains to the first grinder, wherein the substrate is prepared by forming a NiP plating film on a surface of an Al alloy substrate; and a finish polishing step of polishing the substrate for magnetic recording media following washing, using a second grinder while supplying a polishing liquid containing colloidal silica abrasive grains, after washing the substrate for magnetic recording media, wherein the rough polishing step further comprises a step of stopping supply of the polishing liquid containing alumina abrasive grains and removing alumina abrasive grains from the first grinder by supplying a washing liquid containing no abrasive grains instead at the end of the rough polishing step; the method of producing a substrate for magnetic recording media further comprises an intermediate polishing step provided for polishing the surface of the substrate for magnetic recording media using the first grinder while supplying a polishing liquid containing colloidal silica abrasive grains after the rough polishing step and before the finish polishing step; and an average particle size for the colloidal silica abrasive grains used in the finish polishing step is smaller than an average particle size for the colloidal silica abrasive grains used in the intermediate polishing step.