LASER CLADDING OF COLMONOY 6 PARTICLES ON INCONEL 625 SUBSTRATE: MICROSTRUCTURE AND CORROSION RESISTANCE

Abstract

Inconel 625 (IN 625) is a widely recognized nickel-based superalloy due to its high tensile strength, better fabricability, capability to prevent crack formation, acceptable corrosion resistance, etc. However, during the long-term usage, the formed oxide layers are converted into dichromates which reduce the anti-corrosion behavior. This study attempts to improve the anti-corrosion characteristics of IN 625 by cladding it with Colmonoy 6 particles. Further, the corroded morphology, microstructure, hardness and roughness were analyzed. Results showed that the cladded specimens are rich in dendritic and interdendritic areas. These areas are reported to contain rich carbides and borides of Cr that are formed after cladding. These precipitates paved the way for improving the hardness of the Colmonoy-6-cladded layer (7.54 GPa) when compared with the base material (4.49 GPa). A strong and continuous passive film was reported on the cladded samples during the corrosion test which protects the cladded layer. Further, EIS study also reported that the Colmonoy-6-cladded specimens experience higher polarization resistance values due to the stable passive film and lower [Formula: see text] values from the surface roughness measurements. Among the base and cladded samples, the 27-h cladded sample provides better corrosion resistance with greater [Formula: see text] (142,940). In addition, this sample has the minimum roughness ([Formula: see text]m) value than the other samples.