Dense YSZ Coatings Fabricated by Plasma Spray-Physical Vapor Deposition

In the present work, YSZ coatings were deposited on graphite substrates by plasma spray-physical vapor deposition (PS-PVD) in order to study the influence of spray distance on microstructure and durability. Four coating samples were examined in detail via SEM and XRD analysis. The results show that the as-sprayed YSZ has a dense lamellar-columnar microstructure with low porosity. Both monoclinic and tetragonal zirconia were detected in the coatings along with ZrO₂-x, the latter indicating that oxygen loss occurred at short spraying distances. Coating hardness and Young’s modulus were also measured and were found to vary with spraying distance as well.