| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing aluminum hard disk substrate using a polishing method, capable of achieving a high polishing speed without using alumina abrasive grains and providing favorable surface smoothness.SOLUTION: In manufacture of the aluminum hard disk substrate, after nickel-phosphorous plating, polishing is performed in two or more stages. A rough-polishing step before a final stage is performed using a first polishing agent composition including wet-process silica obtained via a pulverization step, a first colloidal silica, and water. The final-stage finish polishing is performed using a second polishing agent composition including a second colloidal silica, a phosphorous-containing compound, and water. Then, an average grain size of the first colloidal silica is smaller than that of the wet-process silica, and the average grain size of the second colloidal silica is smaller than that of the first colloidal silica. Further the first polishing agent composition and the second polishing agent composition have pH values of 0.1-4.0.SELECTED DRAWING: None |
