Abstract
The aim of this study is to improve the surface properties of carbon fiber reinforced polymers (CFRP) to facilitate the deposition of a ceramic erosion-resistant coating by air plasma spraying (APS). To avoid mechanical damage induced by grit blasting, the CFRP substrate was chemically etched to remove the majority of superficial epoxy, which is responsible for the poor adhesion of ceramic coatings. Chemical etch times of around 5 min were found to be the most effective, although remaining regions of epoxy interfered with the formation of alumina coatings. To overcome the problem, plasma spray parameters were adjusted, resulting in high-velocity, partially melted alumina particles capable of removing epoxy left on substrate surfaces. Using a combination of chemical etching and the modified spraying process, continuous 50 µm thick alumina coatings are achievable on polymer-matrix composite substrates.
