Improving the Corrosion Resistance of Thermal Barrier Coatings against CMAS by Depositing top ceramic layer of Enhanced Splat Bonding

The corrosion resistance of the ceramic coatings against CMAS deposit at high temperature is significantly affected by the microstructure of the coatings. Enhancing the bonding ratio between the splats in coatings significantly reduces the inter-connected pores and then obstructs the penetration of the CMAS. In this study, La₂Zr₂O₇ coatings with different lamellar bonding ratios were deposited by changing deposition temperature. The microstructure and properties of the La₂Zr₂O₇ coatings with CMAS deposited on after thermal exposure at 1250°C for different durations were characterized. It was clearly revealed that by adjusting the microstructure and designing a ceramic layer with high bonding ratio on the top of the conventional ceramic layer, the corrosion resistance of the thermal barrier coating could be enhanced. Moreover, by designing multilayer-structured TBCs composed of a porous layer and well-bonded layer, the TBCs with high CMAS corrosion resistance and low thermal conductivity can be achieved.