POLISHING AGENT COMPOSITION AND METHOD FOR POLISHING MAGNETIC DISK SUBSTRATE

摘要

Provided is a polishing agent composition which enables both the achievement of high polishing rate and the achievement of good surface smoothness at the same time without using alumina particles. A polishing agent composition which contains a colloidal silica having an average particle diameter of 5-200 nm and pulverized wet-method silica particles having an average particle diameter of 0.1-1.0 μm. The value of the ratio of the average particle diameter of the wet-method silica particles to the average particle diameter of the colloidal silica is 2.0-30.0.