Abstract
Plasma spraying with axial powder injection inside the anode nozzle is a method considered to markedly enhance deposition efficiency and reduce plasma power compared to the most general method of injecting powder at the nozzle exit. However, powder injecting inside the nozzle will also likely cause problems from powder deposition on the nozzle wall and clogging of the particle feed channels. In this study, spherical stainless steel 316 and angular alumina powders with a mean size of 20-40 μm are used to deposit coatings via axial powder injection. The effect of powder feed rate, gas flow rate, and plasma power on deposition efficiency and particle clogging are investigated. The results show that particle clogging can be avoided by reducing powder feed rate and increasing the velocity of the plasma jet.
