The Development and Characterization of Novel Yttria-Stabilized Zirconia Coatings Deposited by Very Low Pressure Plasma Spray

In this investigation, very low pressure plasma spraying (VLPPS) was used to produce yttria-stabilized zirconia (YSZ) coatings through both liquid and vapor deposition. Coatings created by liquid deposition were found to have a microstructure consisting of dense splats, while vapor-deposited layers exhibited a columnar structure similar to coatings produced by e-beam PVD. Columnar microstructure formation was dependent on substrate temperature and vapor flux continuity. Clear evidence of competitive crystal growth was observed in well-defined columnar coatings. Microstructures consisting of layers of splats and columns were also observed.