CMAS corrosion and thermal cycle of Al-modified PS-PVD environmental barrier coating

摘要

Environmental barrier coatings (EBCs) with a tri-layer structure consisting of silicon, mulltite and Yb2SiO5 were deposited by plasma spray-physical vapor deposition (PS-PVD) on SiC/SiC ceramic matrix composite (CMC). To improve the calcium-aluminum-magnesium-silicates (CMAS) corrosion resistance of EBCs, a novel method called "Al-modification of EBCs surface" was proposed, wherein an Al film was first deposited on surface of Yb2SiO5 top coating by magnetron sputtering, and afterwards the vacuum heat treatment was carried out on the Al-deposited EBCs samples. The thermal cycle performance of both as-sprayed and Al-modified EBCs was characterized from 1300 degrees C to the temperature of environmental water. Moreover, the CMAS corrosion property of both types of EBCs at 1300 degrees C has been compared with each other. And the corrosion mechanism between CMAS and Al-modified EBCs has been investigated. The results show that the Al-modified EBCs have a better thermal cycle and CMAS corrosion performance than that of as-sprayed EBCs.