Yttria-stabilized zirconia thick coatings deposited from aqueous solution in a low pressure plasma reactor

A low pressure plasma process has been developed which enables deposition of oxide layers from micro droplets introduced into a reactor. With this process, up to 50 μm thick porous yttria-stabilized zirconia (YSZ) coatings have been deposited. Zirconyl and yttrium nitrates (ZrO(NO3)2 and Y(NO3)3) dissolved in water were used as precursors. These precursors are introduced as micrometric droplets into a plasma discharge. After interacting with the plasma, the droplets are deposited onto the substrate to form the YSZ coating. The velocity and diameter of the solution droplets injected into the reactor were studied with an on-line Particle Dynamics Analyser to propose a mechanism for the formation of the coating. The structure and composition of the coatings have been characterized by Scanning Electron Microscopy (+ EDX) and X-ray Diffraction. The results obtained show that the deposited 7YSZ coatings exhibit a morphology compatible with TBC applications.