The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 13, 2015
Filed:
Mar. 11, 2011
Shoji Sakaguchi, Nagano, JP;
Masaoki Miyakoshi, Yamanashi, JP;
Jun Natsume, Nagano, JP;
Fuji Electric Co., Ltd., Kawasaki, JP;
Abstract
A method of manufacturing a perpendicular magnetic recording medium substrate is capable of reducing the waviness of all wavelength components and a recording medium is capable of reducing contact with a magnetic head to improve the flying stability of the magnetic head. The method includes two polishing operations. The first operation includes polishing a substrate having a Ni—P-based alloy underlayer with a first porous material that includes 0.1 wt % to 25 wt % of alumina, titania, silica, and zirconia abrasive while supplying a first slurry liquid including an organic or inorganic acid and a first abrasive to the underlayer of the substrate. The second operation includes polishing a surface of the underlayer polished in the first polishing with a second porous material while supplying a second slurry liquid including an organic or inorganic acid and a second abrasive with a grain diameter smaller than that of the first abrasive.