High-temperature corrosion behaviour of plasma sprayed lanthanum magnesium hexaluminate coating by vanadium oxide

摘要

Plasma sprayed lanthanum magnesium hexaluminate (LaMgAl11O19, LaMA) coating degraded by molten V2O5 at 710-1050 degrees C was studied. LaVO4, Mg0.388Al2.408O4 and gamma-Al2O3 were the main corrosion products at 710 degrees C and 800 degrees C, while the corrosion products were LaVO4, MgAl2O4, alpha-Al2O3 at 950 degrees C and 1050 degrees C. AlVO4 as an important intermediate corrosion product had strong influences on the formations of gamma- or alpha-Al2O3 at different temperature regions. Recrystallization and hot corrosion happened to LaMA coating simultaneously at 950 degrees C and 1050 degrees C. However, at 800 degrees C, LaMA coating underwent the most serious degradation along the coating thickness direction due to the presence of amorphous phase. (C) 2014 Elsevier Ltd. All rights reserved.