Study on instant droplet and particle stages during suspension plasma spraying (SPS)

Suspension plasma spraying (SPS) is a new process in the field of the atmospheric plasma spraying (APS). The SPS process uses a heterogeneous mixture of liquids and particles. Thus it is possible to process particles with a size between ten to a few hundred nanometres. This leads to completely new or at least improved material features and structures. Notwithstanding the process and the involved mechanisms that lead from a suspension droplet to a molten ceramic droplet and its influence on the generated coating are not yet completely understood. Because of the liquid in the suspension and much smaller particles the process in the plasma is much more complex compared to the APS process. Based on empiric studies including in-flight monitoring of the particles as well as splat and coating analyses a new schematic of the single stages during suspension plasma spraying and their influence on the coating structure will be introduced.