Wetting and spreading behavior of molten CMAS on the laser textured thermal barrier coatings with the assistance of Pt-modification

Gadolinium zirconate (Gd2Zr2O7, GZO) is a promising next-generation material for thermal barrier coatings (TBCs). The molten CMAS (calcium-magnesium-aluminium silicates) will react with GZO and quickly produce dense Ca4Y6(SiO4)6 phase, which can prevent the further penetration of the molten CMAS. However, the large thermal expansivity difference between the dense reaction production and the GZO substrate leads to the delamination of the production layer when encountering the thermal shock effect. Therefore, it is essential to reduce the accumulation of molten CMAS. In this paper, the surface texture was fabricated on the surface of EB-PVD (electron beam physical vapor deposition) GZO-TBCs. And then a thin layer of Pt film was deposited on the laser-textured surface. The purpose is to increase the wetting contact angle between the molten CMAS and TBCs, thus decreasing the accumulation of the CMAS. The results show that the stable contact angle of the molten CMAS on the laser-textured GZO-TBCs increased from the original 16 degrees to 66.3 degrees, but the surface texture was completely corroded after high-temperature wetting. By introducing a thin layer of Pt film over the laser-textured coatings, a stable contact angle of 111.6 degrees was achieved. This is because Pt film successfully prevents the molten CMAS react with GZO.

Automated summary

In this study, a surface texture was fabricated on the surface of EB-PVD GZO-TBCs, and then a thin Pt film was deposited on the laser-textured surface to increase the contact angle between the molten CMAS and TBCs, reducing the accumulation of CMAS.