The chromising process: a novel development

The industrial application of the chromising process started in about 1935. It enjoyed a steady growth until about 1975 but has since declined in importance, being replaced by novel CVD and PVD processes. Its use for corrosion and oxidisation resistance is very small but there are some applications for wear resistance which exploit the high hardness of chromium carbide. A chance observation in the wear pattern and performance of chromised automotive timing chain link-pins, led to the identification of a diffusion coating structure which had not been previously recognised as having enhanced wear resistance. It was the purpose of this research to examine the nature of this novel structure, to determine how it was occurring in practice and to develop a chromising process which could consistently reproduce the desired end product. [Continues.]