Microstructure and high temperature oxidation behavior of laser cladding C22 coating

C22 coating was successfully prepared on TP347H tube by laser cladding. The main goal was to assess the possibility of using laser cladding C22 coating for high temperature oxidation protection of boiler tubes in ultra-supercritical power plant. The microstructure, phase composition, microhardness and high temperature oxidation behavior of C22 coating were investigated. The microstructure evolution, phase constitution and high temperature oxidation behavior of C22 coating and TP347H samples were investigated. The oxidation experiment were carried out at 600 °C, 700 °C, 800 °C for 168 h. The results revealed that C22 coating mainly contain Ni-Cr-Co-Mo solid solution. The average microhardness of coating surface is 1.5 time that of substrate. Coating exhibited superior oxidation resistance at 600–800 °C. A dense and continuous Cr2O3 film was observed in inner layer of coatings. C22 coating can be used as an excellent oxidation resistant coating with wide application prospect. [Display omitted]