abstract |
Provided is a polishing composition for a magnetic disk substrate for achieving not only reduction in waviness of a substrate but also reduction in halation after polishing without decreasing productivity. The polishing composition for a magnetic disk substrate contains colloidal silica, a water-soluble polymer, and water. The water-soluble polymer compound is a copolymer containing a monomer having a carboxylic acid group, a monomer having an amide group, and a monomer having a sulfonic acid group as essential monomers. The water-soluble polymer compound has a weight average molecular weight of 1,000 to 1,000,000. |