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.

Date of Patent:
Apr. 30, 2002

Filed:

Aug. 30, 1999
Applicant:
Inventors:

Kurata Awaya, Tochigi, JP;

Kazuyoshi Nishizawa, Tochigi, JP;

Kiyoshi Tada, Tochigi, JP;

Assignee:

Showa Denko K.K., Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B 5/66 ; C03C 1/900 ; C25D 5/00 ;
U.S. Cl.
CPC ...
G11B 5/66 ; C03C 1/900 ; C25D 5/00 ;
Abstract

Magnetic disk substrates are produced by subjecting glass substrates to at least steps of degreasing, etching, sensitization with tin chloride, activation and sensitivity-enhancing treatment in that order, then plating the pretreated substrates with a nickel/phosphorus film, and thereafter polishing the plated substrates. In the process, the substrates being processed are washed with hot pure water at a temperature of not lower than 50° C. for a period of from 20 to 90 seconds, after the sensitization step but before the activation step, and heated at a temperature of not lower than 70° C. for a period of from 5 to 100 minutes, after the sensitization step but before the nickel/phosphorus-plating step.


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