X. Chang, Chinese Academy of Science, Beijing, China
Thermal barrier coatings (TBCs) , consisting of yttria-partially-stabilized Zirconia (YSZ) top coat and metallic bond coat, are mostly effective to protect the metallic components of the hot section of gas turbines against the high temperature environment. In the paper, the bond coats have been fabricated in different thermal spray processes (vacuum arc spay, high velocity oxygen flame spraying, low-pressure plasma spray, plasma spray, explosive spray) and with and without a post-spray heat treatment. The cohesion strength, high temperature oxidation and corrosion properties and microstructure evolution of different bond coats were investigated. Nanostructured YSZ has been prepared by atmospheric plasma spraying. The microstructure of the coating was characterized by XRD, SEM and TEM. The results showed that ZrO2 coating possessed the laminate structure and poorly consolidated structure. Compared with original nano powder, the grain size of the coating was coarsen, but still were nano-scale. The cohesion strength and thermal impact of the as-spray nano YSZ coating were much higher than the conventional counterpart. The NiCrAlY/nano-structured YSZ has been successfully applied in transition ducts, combustors and static vanes of gas turbine engine.
