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. 27, 2015
Filed:
Oct. 04, 2011
Nobuaki Mukai, Yamaguchi, JP;
Nobuaki Mukai, Yamaguchi, JP;
Toyo Kohan Co., Ltd., Tokyo, JP;
Abstract
Provided are a method for production of a hard disk substrate capable of obtaining a smooth surface of a plating film by electroless NiP plating that is not degraded in, but exhibits corrosion resistance against, an acid solution and such a hard disk substrate. The method for production of a hard disk substrate including an electroless NiP plating film, includes the steps of: a first plating step of immersing a substrate in first electroless NiP plating bath containing an additive having a smoothing effect to form a lower layer of the electroless NiP plating film on a surface of the substrate, the lower layer having an average surface roughness smaller than an average surface roughness of the surface; and a second plating step of immersing the substrate on which the lower layer of the electroless NiP plating film is formed in the first plating step in a second electroless NiP plating bath to form an upper layer of the electroless NiP plating film, the upper layer having corrosion resistance against an acid solution. The resulting plating film has a smooth surface that is not degraded in, but exhibits corrosion resistance against, an acid solution.