Abstract: An aluminium alloy sheet for various discs having good platability is described. The alloy consists essentially of 2 to 6 wt % of Mg, 0.1 to 0.5 wt % of Zn, 0.03 to 0.40 wt % of Cu, 0.01 to 0.30 wt % of Fe and the balance of Al.

Abstract: An aluminum alloy material having a surface suitable for zinc phosphate processing prepared by a process comprising the steps of (1) cleaning the aluminum alloy surface, and (2) forming a composite film layer comprising Zn metal, Ni or Mn metal, and silicon oxide on the surface of the aluminum alloy.

Abstract: Disclosed herein are: (1) a formable bake-hardening type aluminum alloy sheet, containing 0.2-0.7 wt % of Fe, 0.05-0.5 wt % of Cu, 0.5-2.5 wt % of Mg, 0.5-2.0 wt % of Mn and optionally 0.05-1 wt % of Zn under the condition of Fe wt % +(Mn wt %.times.1.07)+(Mg wt %.times.0.27).ltoreq.3.0, and intermetallic compounds of less than 45 microns in size and an areal rate of 0.5-5% as observed from the surface of a rolled sheet and an average crystal grain width smaller than 25 microns; and (2) a method for producing such bake-hardening type aluminum alloy sheets.

Abstract: A method for treating surfaces of magnetic disk substrates of aluminum alloy with an anodic oxide film on the surfaces thereof, the method comprising: dissolving part of the anodic oxide film by an etching treatment to broaden micro pores of the anodic oxide film to a diameter greater than 170 .ANG..

Abstract: According to the present invention, a metal sheet is prepared by subjecting an Al slab, containing at least one element capable of peritectic reaction with Al, such as Ti, Zr and Mo, the amount of the element incorporated in the slab being 0.05 to 0.4% by weight when one element is incorporated and when two or more elements are incorporated, the amount of at least one element incorporated therein being 0.05 to 0.4% by weight and the total amount of the elements incorporated being not higher than 0.5% by weight, to a soaking heat treatment, hot-rolling the slab and then cold-rolling the hot-rolled slab. According to the present invention, the properties required for such metal sheet, namely the strength and formability, can be remarkably improved, and by the hardening treatment, the adherence between fins and tubes can be improved and the heat transfer efficiency can be remarkably elevated in the heat exchangers. Thus, according to the present invention, practically applicable hard thin fins can be provided.