| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a magnetic disk substrate which can improve polishing speed in a rough polishing step and reduce the occurrence of roll-off (end face sagging) and residual abrasive particles (projection defect) after polishing.SOLUTION: The manufacturing method of a magnetic disk substrate includes: a step (1) of polishing a polishing target surface of a polished base plate with polishing liquid composition A containing silica particles A, acid, oxidant and water; a step (2) of cleaning the base plate obtained by the step (1); and a step (3) of polishing the polishing target surface of the base plate obtained by the step (2) with a polishing liquid composition B containing silica particles B and water. The steps (1) and (3) are performed by different polishing machines from each other. The silica particles A are non-spherical silica having &Dgr;CV value of 0.0% or more and less than 10.0%, and an average particle diameter (D1) of 150.0 nm or more and 300.0 nm or less. In the non-spherical silica, a ratio (D1/D2) of the average particle diameter (D1) to a particle diameter (D2) in terms of BET specific surface area is 2.00 or more and 4.00 or less. |
