Investigation of the effect of substrate on formation of chromium- and vanadium carbide coatings by thermal reactive diffusion

In this research, the effect of substrate on the formation of chromium- and vanadium carbide coating was studied by thermal reactive diffusion. The substrate of H13 steel was coated in two kinds of metal and oxide bath with molar ratio of Cr/V=3 for 14 hour at 1000˚C. Carbide coatings including chromium carbide (Cr3C2, Cr7C3), vanadium carbide (V8C7) and the complex carbide phase of Cr2VC2 were formed on H13 steel. The thickness of the carbide coating was 8.5±0.5 µm and 6.5±0.5 µm, respectively in metal bath and oxide bath. The amount of vanadium- to chromium- rich regions in the carbide coating was less than the ratio of vanadium to chromium content in the metal bath. The results of coating in the present study was compared to the results of coating in a similar condition on Ck45 steel. The type of substrate had an important role on the coating thickness and the phase distribution of vanadium- and chromium- rich regions. However, the element distribution in the coating was not affected by the kind of substrate.