Innovative and emerging processes in plasma spraying : from micro- to nano-structured coatings
Résumé
In the context of nanometre-sized structured materials and the perspectives of their technological applications, plasma spray technology is developing to master the coating microstructure at a nanometre scale level. This paper is an attempt to describe (i) the latest advances in the control of the conventional plasma spray process that requires the monitoring of both the plasma jet fluctuation level and particle processing and (ii) the innovative plasma spray processes that have recently emerged. The latter can be ranked in two classes: the processes that use a liquid feedstock where coatings are essentially formed by the impact of molten particles and droplets; and the processes that generally use a powder feedstock where coatings are generated by the condensation of a vapour with possible inclusion of nanometre-sized particles. Their potential applications are briefly presented and it is concluded that they should develop into viable technologies in the near future.