Abstract: Thermal barrier coatings (TBCs) have successfully been used in gas turbine engines for increasing operation temperature and improving engine efficiency. Over the past thirty years, a variety of TBC materials and TBC deposition techniques have been developed. Recently, nanostructured TBCs emerge with the potential of commercial applications in various industries. In this paper, TBC materials and TBC deposition techniques such as air plasma spray (APS), electron beam physical vapor deposition (EB-PVD), laser assisted chemical vapor deposition (LACVD) are briefly reviewed. Nanostructured 7–8 wt pct yttria stabilized zirconia (7-8YSZ) TBC by air plasma spraying of powder and new TBC with novel structure deposited by solution precursor plasma spray (SPPS) are compared. Plasma spray conditions, coating forming mechanisms, microstructures, phase compositions, thermal conductivities, and thermal cycling lives of the APS nanostructured TBC and the SPPS nanostructured TBC are discussed. Research opportunities and challenges of nanostructured TBCs deposited by air plasma spray are prospected.

Key words: zirconia, thermal barrier coating, plasma spray, nanostructure