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:
Mar. 29, 2016
Filed:
Apr. 02, 2013
Toyo Kohan Co., Ltd., Tokyo, JP;
Toyo Kohan Co., Ltd., Tokyo, JP;
Abstract
An object of the present invention is to obtain a hard disk substrate that can have a smooth surface of a plating film through electroless NiP plating and does not have deteriorated corrosion resistance against acid solutions. A method for producing a hard disk substrate of the present invention is a method for producing a hard disk substrate with an electroless NiP plating film, the method including immersing a substrate in a first electroless NiP plating bath containing an additive with leveling action, thereby forming a lower layer of the electroless NiP plating film on a surface of the substrate, the lower layer having smaller average surface roughness than the surface; and immersing the substrate that has the lower layer of the electroless NiP plating film formed thereon through the first plating step in a second electroless NiP plating bath, thereby forming an upper layer of the electroless NiP plating film, the upper layer having corrosion resistance against acid solutions and having a thickness of greater than or equal to 4 μm.