Enhancing anti corrosion properties of plasma-sprayed ZrO2-25 wt% CeO2-2.5 wt%Y2O3 thermal barrier coatings via nanostructure engineering

The current research aimed to enhance the corrosion resistance of (i) the CaO-MgO-Al2O3-SiO2 (CMAS) and (ii) the hot corrosion of the Na2SO4-55 wt%V2O5 environments. Conventional thermal barrier coatings (TBCs) with a composition of ZrO2-25 wt%CeO2-2.5 wt%Y2O3 (micro-CYSZ) were replaced by nanostructured coatings (nanoCYSZ) with a similar composition. This replacement was achieved by applying the desired coatings using the atmospheric plasma spraying (APS) process on IN738LC/CoNiCrAlY. Corrosion and hot corrosion tests were conducted in the CMAS and Na2SO4-55 wt%V2O5 environments at 1100 degrees C and 950 degrees C with 4-h cycles. In terms of resistance to CMAS corrosion and hot corrosion in the Na2SO4-55 wt%V2O5 environment, the nano-CYSZ coating exhibited better performance compared to the micro-CYSZ with a similar composition. The use of nanostructuring, including the formation of dual structures consisting of unmelted nano-sized particles and melted particles in the top layer of the TBC, resulted in delaying the penetration of molten salts and consequently improving the resistance to the CMAS and Na2SO4-55 wt%V2O5 environments.