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 ZrB2 middle layer and SiC Weight percentage on the erosion behavior of SiC/ZrB2– SiC/ZrB2 functionally gradient coating were investigated. For this purpose, SiC gradient coating was prepared via the reactive melt infiltration method (RMI). Afterwards ZrB2–SiC layers containing 10, 20 and 30 wt% SiC and, ZrB2 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 ZrB2–SiC layer between SiC and ZrB2 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/ZrB2-20% wt. SiC/ZrB2 coating had the lowest erosion rate.