ABRASIVE MATERIAL COMPOSITION AND METHOD FOR POLISHING MAGNETIC DISK SUBSTRATE

摘要

Provided is an abrasive material composition with which it is possible to not only achieve a high polishing rate without requiring the use of alumina particles but also obtain satisfactory surface smoothness and edge surface shape. The abrasive material composition comprises colloidal silica, pulverized wet-process silica particles, and a water-soluble high-molecular-weight compound, wherein the water-soluble high-molecular-weight compound is a copolymer having a constituent unit derived from an unsaturated aliphatic carboxylic acid and a constituent unit derived from an unsaturated amide.