Ceramic/fluoropolymer composite coatings by thermal spraying-a modification of surface properties

Al2O3-TiO2/fluoropolymer (PTFE or PFA) composite coatings are characterized by a well-melted ceramic matrix in which rounded polymer particles are randomly distributed. The as-sprayed polymer particles kept at the coatings surface can however be spread thanks to a thermal treatment at 350 °C during 15 min. Unlike the PFA, a large PTFE loss was noticed during the spraying process. Thus, the highest polymer/ceramic ratio is observed in the coatings made with the separated injection of the Al2O3-TiO2 and PFA powders. The lowest friction coefficient is also measured for this coating.