Adsorbability and spreadability of calcium-magnesium-alumino-silicate (CMAS) on Al-modified 7YSZ thermal barrier coating

A dense alpha-Al2O3 overlay was in-situ synthesized on 7YSZ TBC to mitigate the CMAS attack. The adsorbability and spreadability of CMAS on as-sprayed and Al-modified TBCs were investigated. The results show that compared to the as-spared TBC, the Al-modified TBC has lower adsorption mass and smaller spreading area. When the Al-modified 7YSZ coating was subjected to CMAS attack, the presence of large amounts of Al2O3 will accelerate the formation of MgAl2O4 spinel and induce the generation of CaAl2O4 spinel apart from gehlenite Ca2Al2SiO7. Therefore, it can be concluded that Al-modified 7YSZ TBC has better CMAS corrosion resistance than as-sprayed TBC.