The effect of the SiC content on the high duration erosion behavior of SiC/ZrB2– SiC/ZrB2 functionally gradient coating produced by shielding shrouded plasma spray method

Abstract

In this research, the effect of the ZrB 2 middle layer and SiC Weight percentage on the erosion behavior of SiC/ZrB 2 – SiC/ZrB 2 functionally gradient coating were investigated. For this purpose, SiC gradient coating was prepared via the reactive melt infiltration method (RMI). Afterwards ZrB 2 –SiC layers containing 10, 20 and 30 wt% SiC and, ZrB 2 as the outer layer were applied on SiC coated graphite via solid shielding shrouded plasma spraying (SSPS). To investigate the erosion resistance of the coating, the specimens were subjected to oxy-acetylene and propane flame. The results showed that by applying the ZrB 2 –SiC layer between SiC and ZrB 2 coating, due to the gradual change of the coefficient of thermal expansion mismatch and reduction of thermal stresses, erosion resistance improves, so that the coating with 20 wt% SiC with mass and linear erosion rate, −0.072 × 10 −4 g.cm −2 .s −1 , 0.0166 μm s −1 respectively had the best erosion resistance under oxy propane flame. In the oxyacetylene flame test, a similar result was obtained to the oxy propane test and the SiC/ZrB 2 -20% wt. SiC/ZrB 2 coating had the lowest erosion rate.