Title:
磁気ディスク基板用研磨剤組成物
Document Type and Number:
Japanese Patent JP7219101
Kind Code:
B2
Abstract:
The present invention provides a polishing composition, which can achieve high polishing speed without using alumina abrasive grains, while achieving good surface smoothness by reducing shallow pits and reducing waviness, and also achieve reduction of sags on the edge. The polishing composition for magnetic disk substrates contains colloidal silica having an average primary particle size of 10 to 150 nm, pulverized wet-process silica having an average particle size of 200 to 500 nm, and water. Among all silica particles, the colloidal silica accounts for 20 to 80% by mass, and the pulverized wet-process silica particles account for 20 to 80% by mass. And, the proportion of the colloidal silica with a particle diameter of 30 to 70 nm is from 10 to 90% by volume. Furthermore, the ratio of the average primary particle size of the pulverized wet-process silica particles to the average primary particle size of colloidal silica is from 2.0 to 15.0, and the concentration of total silica particles is from 2 to 40% by mass.
Inventors:
Tohru Iwata
Application Number:
JP2019011481A
Publication Date:
February 07, 2023
Filing Date:
January 25, 2019
Export Citation:
Assignee:
Yamaguchi Seiken Industry Co., Ltd.
International Classes:
G11B5/84; B24B37/00; C09K3/14
Domestic Patent References:
| JP2004204155A | ||||
| JP2019008846A |
Foreign References:
| WO2015146941A1 |
Attorney, Agent or Firm:
Ippei Watanabe
Koike Shigeru
Yoshio Nagaoka
Koike Shigeru
Yoshio Nagaoka