Numerical and experimental studies of substrate melting and resolidification during thermal spraying

A good understanding of melting and resolidification of the substrate will help us to achieve better bonding. A numerical model is developed to investigate the solidification of the droplet, and melting and resolidification of the substrate. The molybdenum powder spraying onto three different substrates: a stainless steel, brass (70%Cu) and aluminum by atmospheric plasma spraying has been investigated. The maximum melting depth of the substrate has been measured and compared with the numerical prediction. Experimental results show that the material properties of the splat and substrate and melting temperature of the substrate play the important roles on substrate melting. A dimensionless parameter, temperature factor, has been proposed and served as an indicator for substrate melting.