Patent ID: 8349470

Claim:
A multi-layer metal sheet comprising a core layer of aluminum alloy having first and second sides, wherein said first side of said core layer has an interlayer made of a Zn-containing aluminum alloy positioned between a Zn-containing outer layer and the core layer, the alloy of the outer layer being more electronegative than the alloy of the interlayer, and the alloy of the core being less electronegative than the interlayer, and wherein said interlayer is made of an alloy which comprises about 0.9 to 2.0 wt % Mn, about 0.002 to 0.7 wt % Cu, up to 0.4 wt % Fe, 0.5 to 2.0 wt % Si, up to 7.0 wt % Zn, and the balance aluminum and unavoidable impurities, if any; and said outer layer is made of an Al—Zn alloy which contains a minimum of 3 wt % Zn.