Suspension plasma spraying: Process parameters and resulting coating architecture

Due to the large volume fraction of the internal interfaces, finely structured coatings (nano- or submicronsized) should exhibit better properties than the ones structured at a microscale. Suspension plasma spraying (SPS) appears as a technology permitting to manufacture such coatings and consisting in injecting within a plasma jet a liquid suspension of solid particles. Compared to plasma spraying of micron-sized particles, SPS exhibit several major differences: i) a more pronounced sensitivity to arc root fluctuations requiring to adapt operating parameters; ii) a shorter spray distance; iii) a higher thermal flux transmitted from the plasma jet to the substrate. Several operating parameters, including suspension characteristics and suspension injection parameters, play relevant roles in the suspension processing and the resulting coating architecture.