Sulfate-vanadate hot corrosion of neodymium cerate/yttria stabilized zirconia composite coating

Neodymium cerate (Nd2Ce2O7) was laboratory synthesized by solid-state reactions of neodymia and ceria and spray dried to get the feedstock for plasma spraying. Hot corrosion behavior of air plasma sprayed 10% Nd2Ce2O7/yttria stabilized zirconia (YSZ) topcoat was studied in the presence of V2O5 and Na2SO4 salts at 950 degrees C for 10-60 hours. It was observed that due to the presence of relatively higher basic compounds Nd2O3 and CeO2 (form Nd2Ce2O7) than Y2O3 in YSZ changed the reaction dynamics during hot corrosion and the major part of corrosive (NaVO3) was consumed by Nd of Nd2Ce2O7, making NdVO4. The Y2O3 of YSZ contributed in the corrosive reaction partially, relieving majority tetragonal zirconia (t-ZrO2) in topcoat (YSZ). No remarkable cracking was developed in the topcoat even after 60 hours of accelerated hot corrosion, which was attributed to the retention of in-relief t-ZrO2 in YSZ.