Anti-CMAS corrosion mechanism of Al2O3 pore sealing and laser remelting on thermal barrier coatings

The sol-dip-coating method and surface laser remelting technology are applied to form an Al2O3 layer on a YSZ coating surface to effectively block the environmental sediment CMAS. The behaviour and mechanism for CMAS corrosion of the coating are investigated, and the interfacial reliability of the coating and matrix is calculated by using the Monte Carlo method. The bonding force between the Al2O3 sol and YSZ coating can be effectively improved by laser surface treatment. Samples subjected to a laser pretreatment and posttreatment (YL-AL) of the YSZ coating are found to show the best interfacial bonding strength between Al2O3 and YSZ. Furthermore, the YL-AL sample shows a higher CMAS resistance than the laser posttreatment (Y-AL) samples, which effectively combines the chemical resistance of Al2O3 to CMAS and the physical resistance of the laser re-melted densification layer against CMAS penetration.