The formation of chromium carbide during chromizing

The carbides formed during the chromizing of various types of carbon and chromium steels are considered in terms of the ternary phase diagram. A correlation is found between the carbide or carbides formed and a diffusion couple model. In low chromium, high carbon steels, an intermediate layer is formed which seems to be a (Fe,Cr)₃C cementite phase. The carbide which is formed on low carbon constructional steels depends on the detailed carbon and chromium profiles. Data found in the literature support the present interpretation.