Preparation and corrosion resistance of Inconel 625 laser cladding coating for high temperature supercritical carbon dioxide environment

This study investigated the development of laser cladding Inconel 625 coating to enhance the corrosion resistance of low alloy steel in high temperature supercritical carbon dioxide (S-CO 2 ). An orthogonal experiment was used to optimize laser cladding process parameters, followed by systematic investigations into the microstructure, bonding strength, and corrosion performance of the laser cladding coatings. Results indicated that the optimized laser cladding Inconel 625 coating exhibited superior surface quality and excellent metallurgical bonding with the substrate. The microstructure of the laser cladding coating consisted of γ-phase and Laves phase, featuring planar, cellular, columnar, and equiaxed dendrites from the bottom to the surface. After 1000 h of exposure to high temperature S-CO 2 , the 15CrMo steel substrate formed a duplex oxide layer that failed to prevent carbon penetration, accompanied by severe spallation of the oxide scale. In contrast, the laser cladding coating developed a dense and continuous Cr 2 O 3 oxide layer, while an underlying amorphous SiO 2 layer effectively inhibited carbon diffusion, demonstrating excellent resistance to S-CO 2 corrosion. This laser cladding Inconel 625 coating technology can be applied in S-CO 2 systems to improve the corrosion resistance of alloys prone to oxidation/carburization.