POLISHING COMPOSITION

摘要

For aluminum disks and glass-made hard disks, those disks having a mean waviness of less than 3 .ANG. are being desired in order to increase th e density of memory capacity. The present invention provides polishing compositions that can give smoothly polished surfaces for the disks. The polishing compositions are polishing compositions for aluminum disks or substrates having silica on the surface thereof, which contain colloidal silica particle groups having different particle size distributions and have a SiO2 concentration of 0.5 to 50% by weight.