Modelling of dry ice blasting and its application in thermal spray

Dry ice blasting, as an environmentally–friendly method, was used during atmospheric plasma spraying for improving coating properties. This process is believed to be capable of reducing the porosity and the oxide of the coating and increasing the deposition efficiency, etc. Considering dry ice pellets are carried and accelerated by compressed air through a convergent–divergent nozzle, the computational fluid dynamic approach was first employed in this study to evaluate the effects of nozzle geometry, accelerating gas conditions as well as properties of pellets, on the pellet velocity variation and further to optimise the process. Moreover, the experiment with a steel powder was then carried out and the results indicate that a denser coating with a lower content of oxide can be achieved with the application of dry ice blasting during the plasma spraying.