Manufacture of aluminum-alloy substrate for magnetic disk

Abstract

Abstract PURPOSE:To develop an Al-alloy substrate for high-density magnetic disk minimal in coarse intermetallic compound content and also reduced in memory error, by subjecting a molten Al-Mg-Zr alloy to rapid solidification into sheet- like state and then by applying cold rolling to the above under specific conditions. CONSTITUTION:The molten Al alloy containing 3-5.5% Mg and 0.01-0.10% Zr as essential components and also containing Fe and Si as impurity elements by <=0.10% and <=0.10%, respectively, is subjected to rapid solidification at >=50 deg.C/sec cooling rate into a plate of 2-10mm thickness so as to allow impurities such as Fe, Si, etc., to enter into solid solution, so that precipitation of coarse intermetallic compounds is inhibited and an Al-alloy plate having extremely fine structure is formed. The above plate is cold-rolled at 30-85% draft to be formed into sheet-like state of 2mm thickness and the resulting cold-rolled sheet is annealed at 240 deg.C for 1hr. In this way, the Al-alloy substrate for high-density magnetic disk minimal in the content of intermetallic compounds as coarse as >=5mum grain size and reduced in memory error can be obtained.

Inventors

• 👤 Teruo Uno
• 👤 宇野　照生
• 👤 Seiichi Hirano
• 👤 平野　清一
• 👤 Yoshio Watanabe
• 👤 良夫 渡辺

Bibliographic Details