Abstract
Black colored steel sheet, produced by treating with Cr(VI) treatment and resin on Zn-Ni electroplated steel sheet with a blackening process, has been successfully used for office automation equipment, audio equipment and household electrical appliances. Recently, in reply to the social requirement of eliminating Cr(VI), which is one of the environmentally un-friendly materials, Cr(VI) free treated blackening Zn-Ni electroplated steel sheet has been developed. Newly developed Cr(VI) free type black colored steel sheet consists of over 1μm. thick organicinorganic composite film on black treated Zn-Ni electroplated steel sheet. This Cr(VI) free type black colored steel sheet shows the same appearance, corrosion resistance, change of color after press formation, friction coefficient, surface electrical resistance and resistance to alkaline degrease reagent to comparison with those of Cr(VI) type black colored steel sheet.
