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:
May. 02, 1989
Filed:
Jul. 07, 1986
Kazuo Yamada, Mishima, JP;
Masahiro Tsuchiya, Susono, JP;
Hideaki Kakita, Susono, JP;
Reijiro Maruyama, Tokyo, JP;
Yoshinobu Okada, Numazu, JP;
Yo Takeuchi, Susono, JP;
Mitsubishi Aluminum Kabushiki Kaisha, Tokyo, JP;
Abstract
A substrate for a magnetic disc prepared from an aluminum alloy which consists essentially of from 3.0 to 5.0 percent, preferably from 3.5 to 4.5 percent, Mg, from 0.5 to 3.0 percent, preferably from 0.5 to 1.7 percent, Zn, and the balance Al and inevitable impurities. The inevitable impurities contain not more than 0.10 percent Si, not more than 0.10 percent Fe, not more than 0.01 percent, Mn, not more than 0.01 percent Cr, not more than 0.01 percent Ni, and not more than 0.01 percent Ti. The aluminum alloy substrate may also contain from 0.3 to 2.0 percent, preferably from 0.5 to 1.0 percent, Cu, and/or from 0.02 to 0.5 percent, preferably from 0.05 to 0.2 percent, Zr. The aluminum alloy substrate for a magnetic disc has a structure wherein fine and uniform intermetallic compounds are present in the matrix metal, with almost no non-metallic inclusions present therein, and which has high hardness and high strength, thereby making it possible to provide a magnetic disc (1) having improved surface smoothness and (2) of reduced thickness. The disc substrate can be coated to provide high density magnetic recording.