Flash Boiling Atomization of High-Concentration Suspensions in Suspension Plasma Spraying

This study aims to investigate the advantage of using flash boiling atomization as a new method of feedstock injection in suspension plasma spraying (SPS) and compare the results with continuous jet injection at ambient temperature that is currently used in SPS. In conventional methods, clogging is the main obstacle for the injection of suspension with concentrations beyond 40 wt.%. In this work, we demonstrate that flash boiling atomization enables the injection of suspensions with solid concentrations up to 70 wt.%. The chosen suspension was water based, and the average diameter for the dispersed titania particles was 500 nm. Coating characterization, phase composition, deposition efficiency, deposition rate and thickness per pass were investigated for different suspension concentrations. It was shown that using suspensions with high solid contents leads to a significantly higher deposition weight per pass and thickness per pass and results in a different coating microstructure.