Initial phase hot corrosion mechanism of gas tunnel type plasma sprayed thermal barrier coatings

摘要: Abstract The hot corrosion resistance of the top layer in TBC is one main constructive factors which determines lifetime coatings under critical operating environments. In present study, 8 wt% yttria stabilized zirconia (8YSZ), lanthanum zirconate (La 2 Zr O 7 ) and equal weight percentage its composite (50%8YSZ + 50% La were prepared by using gas tunnel type plasma spray torch at optimum spraying conditions. performances above thermal barrier examined against 40 wt%V 5 –60 wt%Na SO 4 corrosive ash 1173 K for 5 h open air atmosphere. After hot-corrosion testing, coating surface was studied a scanning electron microscope to observe microstructure X-ray diffraction techniques used identify phase compositions. results showed that LaVO YVO are products along with ZrO transformation from tetragonal monoclinic phases 8YSZ respectively. formation mechanism varied each among these, composition 50%8YSZ + 50%La exhibited least degradation V –Na environment compared other coatings.