Life time dependency on the pre-coating treatment of a thermal barrier coating under thermal cycling

A thermal barrier coating system consisting of the single crystalline Ni-based superalloy CMSX 4, a Pt aluminide bond coat and an EB-PVD processed ceramic top coat was thermally cycled in order to study the influence of three different treatments prior the deposition of the ceramic top coat. Besides the standard treatment, one type of treatment was annealing in vacuum, while the other was annealing in an O containing ArH atmosphere; in both cases for 4 h at 1080 °C. ed to the standard treatment, annealing in vacuum almost doubled and annealing in ArH atmosphere almost tripled the cyclic life time of the ceramic coating. The improvement was related to the creation of a defined alumina scale before and during TBC deposition.