MN-ZN TWO-LAYER PLATING STEEL SHEET WITH AN EXCELLENT CORROSION RESISTANCE, ADHESION AND PLATING PROPERTIES AND PROCESS THEREFOR

摘要

The steel sheet having excellent corrosion resistance and adhesion property comprises a lower Zn layer of above 5 g/m2 and a upper Mn layer of 2-50 g/m2. The plating method comprises; (a) placing Mn vaporising source charged with Mn in a vacuum chamber; (b) evacuating the vacuum chamber to less than 1 x 10-4 torr; (c) heating the conventional Zn- plated steel sheet as a substrate in a range of 50 to 300 deg.C; (d) degassing the vaporising source by introducing a current; and (e) vacuum depositing the Mn onto the Zn-plated substrate by opening the covered shutter of Mn vaporising source.