材料期刊网

A new process has been developed for colouring stainless steel. Various colour films could be obtained by using alternating voltage (AV) passivation in hot sulphuric acid solution. Unlike the INCO process, this process is operated in a bath containing no chromic acid, which is toxic to the environment. The desired colours can be obtained by adjusting the alternating electric field parameters. Corrosion tests show that the coloured film has a higher corrosion resistance than chemically coloured film. The coloured steel may be subjected to metal forming operations without detriment to the film; the coloured film also shows excellent wear resistance.