| 摘要 |
PROBLEM TO BE SOLVED: To provide an aluminum alloy substrate for a magnetic disk in which a surface having high flatness and high smoothness can be obtained without micro-waves generated on the surface even after NiP plating, and with which the density of a magnetic disk can be increased, and to provide a production method therefor. SOLUTION: The substrate comprises, by mass, 3.0 to 6.0% Mg, 0.01 to 0.2% Cu, 0.25 to 1.0% Zn and 0.02 to 0.2% Cr, and the balance Al with inevitable impurities. Among the inevitable impurities, the content of Fe is controlled to≤0.05%, the content of Si is controlled to≤0.05%, and each content of the other inevitable impurity elements is controlled to≤0.02%. The number of Al-Mg-Zn based intermetallic compounds with the maximum width of≥0.02μm and the maximum length of≥0.1μm present in the grain boundaries is controlled to one or more pieces on the average per mm. COPYRIGHT: (C)2004,JPO
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