Thermal cycling behavior and hot corrosion performance of the plasma sprayed Er2Si2O7 coatings deposited on Cf/SiC composites

Abstract Rare-earth based disilicates are promising coating materials for C f /SiC composites. In this study, Er 2 Si 2 O 7 coating was deposited on the C f /SiC substrate by atmospheric plasma spraying using the solid-state reaction synthesized powders. Sintered Er 2 Si 2 O 7 coupons derived from the synthesized powders were subjected to dilatometric studies showing the average value of 4.3 ppm/°C for the coefficient of thermal expansion. The coated C f /SiC coupons were thermally cycled between 400 °C and 1500 °C on a burner rig facility until failure of coating. Meanwhile, hot corrosion performance of the free standing plasma sprayed Er 2 Si 2 O 7 coating coupon was evaluated by using molten vanadate salt with loading of 15 mg/cm 2 at 800 °C. Analytical techniques such as X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy were applied to study the microstructural characteristics of the powders and coatings before and after thermal cycling and hot corrosion tests. Coatings’ degradation as a result of thermal cycling and hot corrosion tests was investigated in terms of microstructure and microchemistry transformations.