COLORED CONVERSION FILMS OF MO-S-CU CLUSTER COMPOUNDS ON A COPPER SURFACE

Conversion films of Mo-S-Cu cluster compounds with a metallic luster o f various colors have been obtained on a copper surface; their colors have been changed by heat treatment. Accelerated corrosion and tarnish tests indicate that PMTA passivation enhances the anticorrosive abili ty of the conversion films and the stability of their colors. FT-IR, X PS and AES determinations were made to investigate these conversion fi lms before and after being heated. The results show that the colors of the heated and unheated films are probably caused by Mo-S-Cu bonds an d a statistical distribution and overlapping of various molecular laye rs inasmuch as the films are complicated multicomponent and multilayer systems. The disparity of colors before and after heating treatment i s caused by change of composition and structure of the films.