Laser Treatment of Columnar YSZ Coatings Produced by Suspension Plasma Spraying

Thermal barrier coatings (TBCs) protect turbine engine components allowing them to operate at high temperatures, significantly improving turbine power and fuel efficiency. Suspension plasma spraying (SPS), a modern coating technique, is gaining attention for its ability to create columnar microstructures that balance porosity, reduce thermal stresses, and lower thermal conductivity. However, the columnar structure can also facilitate the penetration of calcium–magnesium–alumino-silicates (CMAS), which leads to TBC deterioration. To mitigate this, a laser post-treatment process has been proposed to remelt the top layer of TBCs, forming a barrier that prevents or reduces CMAS infiltration. In this study, columnar yttria- stabilized zirconia (YSZ) topcoats were deposited by SPS. A laser treatment was used to create a remelted layer at the surface of the SPS coatings. The influence of key laser parameters, such as scanning speed and laser power, on the microstructure of the remelted top layer of the columns in the SPS coatings was investigated. It is hypothesized that such a process could significantly improve the durability and performance of SPS deposited TBCs by minimizing CMAS penetration.