| 摘要 |
PROBLEM TO BE SOLVED: To provide a polishing composition suitable for applications such as primary polishing of a magnetic disk substrate.SOLUTION: The polishing composition contains first silica abrasive grains having an average aspect ratio As1 and second silica abrasive grains having an average aspect ratio As2 larger than that of the first silica abrasive grains. The average minor axis Dmin1 of the first silica abrasive grains is 30-60 nm, and the average minor axis Dmin1 of the first silica abrasive grains and the average minor axis Dmin2 of the second silica abrasive grains satisfy a relation of 1<(Dmin2/Dmin1)<3. |
