Simulation and Analysis of Residual Stresses in Functionally LZS/CMAS Gradient Coatings on 316L Steel Surface

Based on the high temperature stability, corrosion resistance and wear resistance of glass ceramics, the gradient coatings of Li₂O-ZnO-SiO₂ and CaO-MgO-Al₂O₃-SiO₂ were designed and fabricated to improve the corrosion resistance of 316L steel which was selected as candidate materials of pump impeller in lead-cooled fast reactor and to extend its service time.The coating falls off from 316L steel matrix because of their physical property difference.The influence of gradient coating layer number N, thickness H and component distribution index p of Li₂O-ZnO-SiO₂ and CaO-MgO-Al₂O₃-SiO₂ on the thermal stress between gradient coatings and substrate were simulated with ANSYS finite element software, which were compared with that of monolayer coating.The results show that the residual thermal stress of gradient coatings is alleviated significantly.When the gradient layer number N=3, thickness H=0.6 mm and component distribution index p=0.6 are taken, the effect of residual thermal stress relaxation is better.The simulation analysis results can provide theoretical guidance for the optimization and design of the gradient coatings.