Structural stabilization of EBC with thermal energy reflection at high temperatures

Structural stability of an environmental barrier coating (EBC) with thermal energy reflection function that has a periodic layered structure consisting of Y2Ti2O7 (YT) and Al2O3 is essential to maintenance of the EBC performance at high temperatures. The effect of adding Al to YT layer on the structural stability was investigated using model samples in which Al2O3 layer was formed on both the YT and Al-doped YT (AYT) substrate by aerosol deposition (AD). Exposure to heat selectively dissipated the Al2O3 layer on the YT substrate near the interface between the layer and the grain boundaries of the substrate. In contrast, the Al2O3 layer on the AYT substrate remained intact upon heating when Al was added at the solid solution limit. The Al2O3 layer was found to exhibit a pronounced degree of (0001) basal plane texture. An increase in the impact velocity of particles during AD effectively developed the basal fiber texture.