Surface treatment of metallic sheet was developed with respect to a copper substrate and a blacked chromium compound layer, wherein the treated surface of the chromium compound layer is covered with fine, upright, scaly protrusions.The developed copper sheet kept excellent adhesion strength to a resin layer even after high temperature treatment or high moisture treatment, which was considered to be come from an anchor effect of said layer structure.A blacked chromium compound layer showed high resistance to the salt spray test and it also showed excellent adhesion stability with substrate in deep drawing or bending deformation. The above characteristic of blacked chromium compound layer was considered to be come from thin thickness of amorphous layer, wherein the elemental ratio of oxygen/chromium changes in moving out from the boundary between the substrate and the surface layer. The developed copper sheet has a possibility to be applied high performance electronic and electrical components.
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