Influence of the Powder Morphology and Plasma Spray Process Parameters on the Structure and Properties of Al₂O₃ Based Plasma Sprayed Coatings Available to Purchase

In this investigation, alumina powders prepared by different methods were sprayed on carbon steel substrates using a conventional plasma torch with radial injection. The spraying process and powder injection parameters were varied and the injection behavior of the powder was studied. Changes in particle acceleration, deceleration, and impact were measured with novel spray diagnostic equipment and are correlated with the structure and properties of the coatings obtained. Dense coatings were achieved with several agglomerated-and-sintered Al₂O₃ powders, although higher impact velocities and temperatures were recorded for the larger and denser fused-and-crushed particles.