Feather-like Structured YSZ Coatings at Fast Rates by Plasma Spray Physical Vapor Deposition

A variety of yttria-stabilized zirconia (YSZ) coatings have been attained by plasma spray physical vapor deposition (PS-PVD) with fine YSZ powders at high power. The coating structures were found to change significantly with the powder feeding rates but less with the substrate temperature and the rate of the substrate rotation, and a porous feather like structure was attained at 500 Torr (666.6 millibar) and a rate of >200 μm/min. Such a coating produces porosity reaching >50%, thermal conductivity as small as 0.5 W/mK and lower infra-red transmittance compared to the sprayed splat coating with identical thickness.