Investigation of Single Layer and Bilayer of Plasma Transferred Arc (PTA) Coatings of Fe-Cr-V Powder

This paper presented an investigation result of single layer and bilayer of PTA coating of two different Fe-Cr-V powder commercially available and an improvement of the surface hardness by adding 35% of WC. In case of single layer, the microstructure was uniform across the thickness and also the hardness, while microstructure of the bilayer was obviously separated between interlayer and topcoat. The bilayer coating microstructure was changed, and approaching the topcoat, the microstructure was similar to single layer. The hardness of bilayer was decreased due to the dilution. After adding WC into the powder, the microstructure was changed and it could be seen that WC particles distributed across the coating. The hardness was increased due to dilution of some WC. Moreover, in all cases, PTA process offered coating with no crack and no re-precipitated with only small pores. However, adding WC could result in bigger pore size.