High temperature wettability between CMAS and YSZ coating with tailored surface microstructures

In the present work, the wetting behavior of molten calcium-magnesium-aluminum-silicate (CMAS) on femtosecond laser ablated YSZ coatings is comparatively studied. The results suggest that femtosecond laser ablated coating possesses smaller initial contact angle compared with as-sprayed or polished YSZ coatings, but lower spreading rate and larger equilibrium contact angle. This difference can be attributed to: 1) restricted CMAS spreading by the ablated squares through pinning the solid-liquid-vapor triple-phase contact line; 2) retarded CMAS penetration by microrod-shaped structure inside the ablated squares. This study provides an effective method to improve the CMAS resistance of YSZ coating by femtosecond laser.