Hot corrosion behaviour of plasma sprayed YSZ/LaMgAl11O19 composite coatings in molten sulfate–vanadate salt

Hot corrosion studies of thermal barrier coatings (TBCs) with different YSZ/LaMgAl11O19 (LaMA) composite coating top coats were conducted in 50 wt.% Na2SO4 + 50 wt.% V2O5 molten salt at 950 °C for 60 h. Results indicate that TBCs with composite coating top coats exhibit superior oxidation and hot corrosion resistances to the TBC with the traditional YSZ top coat, especially for which has a LaMA overlay. The presence of LaMA can effectively restrain the destabilization of YSZ at the expense of its own partial degradation. The hot corrosion mechanism of LaMA coating and the composite coatings have been explored.

► New YSZ/LaMgAl11O19 (LaMA) composite coatings have been developed.
► The presence of LaMA slows down the degradation of YSZ in molten salt environment.
► LaMA coating can be degraded by molten sulfate–vanadate salt attack.
► The hot corrosion mechanism of LaMA coating has been proposed for the first time.
► Bilayered or graded YSZ/LaMA modes may be the good selections for advanced coatings.