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:
Sep. 23, 1980
Filed:
Oct. 19, 1978
Pravin K Patel, Los Angeles, CA (US);
David H Johnston, Redondo Beach, CA (US);
John Makaeff, deceased, late of Los Angeles, CA (US);
Poly Disc Systems, Inc., Torrance, CA (US);
Abstract
A new and improved magnetic recording disk can be prepared by interposing between an aluminum substrate disk and a recording alloy layer a support layer located on the substrate disk and a shield layer located between the support layer and the recording layer. The support layer is a hard, semi-crystalline nickel alloy layer having magnetic properties which is of such a character that if it is contacted by a recording head during the use of the disk it will tend to form a powder which will not interfere with subsequent use of the disk or recording head. The shield layer is of a nonmagnetic metal and serves to reflect signals from the recording head so that they do not reach the support layer. The support layer is created by forming an electroless nickel alloy deposit in the substrate and subsequently heating this deposit at a temperature which will not cause warpage of the substrate but which cause the deposit to change to a desired physical form while concurrently causing diffusion of nickel into the substrate. Such diffusion has the effect of increasing the amount of the alloying element in the support layer and firmly bonding the support layer to the substrate.