Patent ID: 8932110
Filing Date: 2015-01-13
Classification: B24B,C09G,C09K,G11B

Abstract:
1. A method of manufacturing a perpendicular magnetic recording medium substrate, comprising: first polishing a surface of an underlayer made of a Ni—P-based alloy with a first porous material, having an abrasive mixed in the first porous material prior to the first polishing in an amount that is in a range of from 3 wt % to 20 wt % of the weight of the first porous material, while supplying a first slurry liquid including an organic acid or an inorganic acid and a first further abrasive to the underlayer, the underlayer being of a substrate, and the abrasive mixed in the first porous material prior to the first polishing being an abrasive selected from a group consisting of alumina, titania, silica, and zirconia, and having an average grain diameter ranging from 5 nm to 300 nm and smaller than that of the first further abrasive; and second polishing the surface of the underlayer polished in the first polishing with a second porous material while supplying a second slurry liquid including an organic acid or an inorganic acid and a second further abrasive with an average grain diameter smaller than that of the first further abrasive.