| 摘要 |
PROBLEM TO BE SOLVED: To provide an aluminum alloy sheet for magnetic disk, minimal in the occurrence of pits and nodules, and its production. SOLUTION: This alloy sheet is an aluminum alloy sheet having a composition which contains, by weight, 0.05-0.15% Cu, 2-6% Mg, 0.1-0.3% Zn, 0.05-0.12% Zr, and either or both of >0.01-<0.05% Mn and >0.01-<0.05% Cr and also contains, as impurities, Si, Fe, and Ti in the amounts controlled to <=0.1%, <=0.1%, and <=0.02%, respectively, and has the balance Al with inevitable elements and in which the relation of 2Cu+6Zr-3Zn=0.15 to 0.32% is satisfied and the contents of the inevitable elements are regulated to <=0.02%, respectively. It is desirable that, in the surface layer of the aluminum alloy sheet, the number of Mg2 Si and Al-Fe intermetallic compounds, having >5μm major axis, per unit area is regulated to <=20pieces/mm<2> .
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