Factors influencing the penetration depth of molten volcanic ash in thermal barrier coatings: Theoretical calculation and experimental testing

Abstract

Volcanic ash (VA) corrosion is a critical factor accelerating the failure of thermal barrier coatings (TBCs). The service life of the TBCs corroded by molten VA is controlled by its penetration depth. Here theoretical model as well as experimental testing is carried out to systematically investigate the factors influencing the penetration depth of VA. The results demonstrate that the most significant factor is the temperature, followed by the infiltration time and VA amount, while both exhibit more obvious effect than the surface roughness of TBCs. Furthermore, a theoretical approach to inhibit the penetration of VA is also proposed based on Cassie model. Keywords: Thermal barrier coatings, Volcanic ash, Modeling, Infiltration