Thermal barrier coatings deposited by laser CVD

The ceramic coating is a key issue for thermal barrier coatings (TBCs) in gas turbine technology. Atmospheric plasma spray (APS) and electron-beam physical vapor deposition (EBPVD) are commonly employed in practical applications. An alternative route, chemical vapor deposition (CVD), is a candidate process for TBCs. Although CVD has been understood to be too slow to obtain thick coatings, a laser CVD process has achieved an extremely high deposition rate (660 μm/h) for yttria-stabilized zirconia (YSZ) coatings. The high deposition rates have caused a large number of nano-pores in grains leading to a significantly smaller thermal conductivity of 0.7 W/mK. This paper briefly reviews the process for TBCs, and introduces laser CVD for thick oxide coatings.