This study was conducted to improve four characteristics as objectives:（1） high current efficiency, （2） surface brightness, and （3） hardness of chromium-carbon （Cr-C） alloy layers during electrochemical deposition from Cr（III） ions, （4） reproducibility the Cr-C layer formation repeated plating with a electroplating bath. A malonic-acid-containing sulfuric acid bath （sulfuric II） prepared by add...