| 摘要 |
PURPOSE:To manufacture a vertical magnetic disk of high quality in simplified stages by using a lightweight alpha-type Ti alloy having high strength as the material of a substrate and by directly forming a vertically magnetizable Co-Cr film on the Ti alloy substrate without forming a surface-treated layer such as an Ni-P layer and an intermediate layer such as a thin Ti layer. CONSTITUTION:A substrate for a vertical magnetic disk is made of a lightweight alpha-type Ti alloy having high strength and a hexagonal columnar structure and suitable for the satisfactory C-axis orientation of a Co-Cr film. Since the Ti alloy has high strength, a surface-treated layer is made unnecessary, an excellent surface state required by a high density substrate for a magnetic disk can be provided by direct polishing, and waving is perfectly prevented. A Ti alloy is classified roughly into three kinds, that is, alpha type, alpha+beta type and beta type, and only the alpha type Ti alloy is suitable for the C-axis orientation of a Co-Cr film. A polyimide or polyester layer may be formed on the Ti alloy substrate to improve further the C-axis orientation of the Co-Cr film. |
