Abstract
Our previous experiments with low-cost steel substrates confirmed that individual steps of conventional thermal barrier coating (TBC) deposition may influence fatigue properties of the coated samples differently. In this study, testing was carried out for TBC samples deposited on industrially more relevant Hastelloy X substrates. Samples were tested after each step of TBC deposition process: as-received (non-coated), grit-blasted, bond-coated (NiCoCrAlY) and bondcoated + top-coated (yttria-stabilized zirconia - YSZ). Conventional atmospheric plasma spraying (APS) with gas stabilized plasma torch was used for deposition of both bond coat and top coat. In addition, for one half of the samples, bond coat was prepared by consecutive combination of HVAF (High Velocity Air Fuel) and APS processes. Samples were tested both in as-sprayed condition and after 100 hours annealing at 980 °C, which simulated in-service conditions. Obtained results showed that different fatigue performance may be expected for various stages of the TBC deposition as well as due to the variation of the deposition process and sample temperature history.
