Stress design of a laminated MoSi2/Cr coating under particle impact and high temperature environment

A protective laminated MoSi2/Cr coating was deposited on SiC coated carbon/carbon composites by plasma spraying. Under particle impact environment, the Cr interface layer could relax stress concentration and rapidly relieve impact stress by 30% in the laminated coating layer by layer, thus keeping inner layers intact according to the experiment and simulation results. Under thermal shock condition, sudden change of thermal stress induced by the Cr interface layer could also help change the crack propagation path, thus keeping the coated sample without mass loss after 30 thermal cycles between 1500 degrees C and room temperature. After 157 h oxidation at 1500 degrees C in static air, the Cr interface layer could also inhibit the formation of penetrating cracks and convert the oxidation mechanism of parabolic mass loss law in MoSi2 coating to linear mass loss law at the final oxidation stage.