Phase stability and initial phase high-temperature corrosion behavior of non-stoichiometric lanthanum cerium oxide thermal barrier coatings

Abstract

Three different compositions of lanthanum cerium oxide thermal barrier coatings with varied cerium oxide (1.8CeO 2 , 1.9CeO 2 and 2.0CeO 2 ) compositions were synthesized and plasma sprayed to achieve free-standing coatings. The phase stability studies showed that the coatings are stable at 1400 degrees C after 100 h. The hightemperature corrosion was performed in the presence of sulfate-vanadate (50 wt%Na 2 SO 4 +50 wt%V 2 O 5 ) at 1000 degrees C for 4 h. The result depicts LaVO 4 as the major corrosive product formed in all three compositions along with CeVO 4 , LaCeVO 4 and CeO 2 . The hot corrosion test result gives information that the composition of CeO 2 greatly influences the hot corrosion resistance. The increase in CeO 2 percentage increases the resistance against the infiltration of molten sulfate-vanadate compounds. This investigation provides a feasible way to understand the coating composition for better hot corrosion resistance in sulfate-vanadate mixtures.