Method of using aluminum alloy as substrate for magnetic discs with enhanced magnetic recording density
US4826737A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1986 |
| Grant date | May 2, 1989 |
| Priority date | — |
| Expiry date | Jul 7, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12764
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.