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°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.