Development of Wear Resistant Ceramic Coatings by HFPD

The high frequency pulse detonation (HFPD) process has shown to be a cost effective spray technique for the deposition of highly dense and erosion resistant YSZ ceramic coatings. In comparison to the coatings produced by conventional APS, a significant improvement of the wear performance can be achieved by the HFPD process as result of the high coating compactness. This work deals with the deposition of different ZrO₂ and Al₂O₃ based ceramic powders by the HFPD technique, for the development of highly dense and wear resistant ceramic layers. During this development, the gun configuration and the process parameters (gas flows, explosion frequency, spray distance and cinematic conditions) have been optimised to get the best deposition performance. The resulting coatings have been characterised in terms of the microstructure, the microhardness and the sliding wear performance under dry conditions. In comparison to the plasma sprayed coatings produced with equivalent process conditions, the coatings deposited with the HFPD process are significantly harder and their sliding wear resistance is two–three-fold higher for YSZ coatings and five-six-fold higher for Al₂O₃ coatings. Furthermore, the HFPD process is able to produce highly dense and hard functional coatings in one spray pass, suitable for wear protective applications.