Laser hybred plasma spray processes : tools to adjust coating structural characteristics

International audienceFive groups of closely interrelated operating parameters (power parameters, feedstock injection parameters, geometric parameters, kinematics parameters and environmental parameters) have to be optimized and controlled during Atmospheric Plasma Spraying (APS) to control the coating structure and its properties in service. Nevertheless, in some cases, the multiple possible combinations of operating parameters do not permit to reach the required coating structural characteristics. Auxiliary systems, such as lasers, can help to decouple interrelated effects and introduce new degrees of freedom to the process. Combining a plasma torch with a laser beam forms a hybrid process. In such a case, several strategies can be implemented, depending on the one hand on the laser irradiation characteristics and, on the other hand, on the location of the laser F irradiation area in regards with the particle impact footprint on the surface. This paper intends to develop several works carry out on laser hybrid plasma spray processes. Substrate surface and coating interface ablation, substrate surface and coating layers preheating and coating layers remelting are presented. Mechanisms resulting from laser irradiation are detailed and some resulting coating structures analyzed