Investigation of Wear and Corrosion Characteristics of Stellite-6 and Stellite-21 Layers Deposited by Co-Axial Laser Cladding

Layers of Stellite-6 and Stellite-21 were deposited on tool steel substrates using co-axial laser cladding process with a goal to obtain hard, wear and corrosion resistant coatings. Clad-layers of the two types of Stellite alloys were investigated and compared in terms of microstructure, hardness and sliding wear resistance. Corrosion tests were also performed to study their corrosion behaviour. Micrographs indicated that both the Stellite grades form dendritic structure. However, there were certain differences in composition of dendritic and interdendritic regions of tungsten (W) containing Stellite-6 and molybdenum containing Stellite-21. Stellite-6 clad-layer was found to be slightly harder than Stellite-21 clad-layer near the top surface. Wear resistance of Stellite-21found to be marginally higher than that of Stellite-6 due to lower coefficient of friction. However, Stellite-21layer was found to be more corrosion resistant. Hence, for application involving mechanical loading and wear, both Stellite-6 and Stellite-21 could be a good choice as a clad-material on engineering components; but if the component is going to be subjected to mechanical loading and wear under corrosive environment Stellit-21 could be a better choice.