| abstract |
(57) [Summary] [PROBLEMS] The following (1) to-newly discovered by the present inventors. Provided is a polishing composition capable of suppressing the occurrence of surface defects having the feature (3). (1) It occurs on a part of or the entire surface of the magnetic disk substrate. (2) 5 nm depth This is a collection of small scratches before and after. (3) The direction of the scratch extends substantially along a specific direction (in most cases, the radial direction of the magnetic disk substrate). SOLUTION: (A) at least one kind selected from formic acid, acetic acid, succinic acid, malic acid, maleic acid, malonic acid, butyric acid, oxalic acid, iminodiacetic acid, dl-mandelic acid and 1-glutamic acid acid salt; ) A polishing composition was prepared from silica and (C) water. |