Study On The EB-PVD Technics For The TPS Outer Layer ZrO₂ Functional Coating

Yttria partial stabilized zirconia ceramic coating was prepared on the matrix of stainless steel by electron-beam physical vapor deposition (EB-PVD) in this paper. The coating phase structure and chemical composition were analyzed by X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS) respectively; the coating surface topography was observed by Scanning Electron Microscopy (SEM) and Atom Force Microscopy (AFM); the residual stress based on the theory computational model was measured and calculated by grazing incidence X-ray analysis (GIXA). The nanohardness and elastic modulus of coating with different thickness was measured by nanoindentation. The thermal shock property was characterized and the coating surface emissivity was measured by radiometer.The result of XRD analysis showed that the coating produced by EB-PVD was Tetragonal phase zirconia with different texture. Size of grain increased with the matrix elevating temperature.The little grain on the coating surface was determined to be the upper surface of columnar crystal by SEM and AFM, and the roughness of the coating surface diminished with increasing distance between the target and the substrate. XPS result indicated that the binding state of top surface Zr-O was Zr⁴⁺, and oxygen-absence was discovered in the internal coating.The residual stress in the coating was press stress which inherited from thermal stress in the process of preparation. The hardness and modulus of the coating was relevant to the thickness. The thinner the thickness of the coating, the better the deformation coordination between the substrate and the coating becomes.The thermal shock performance reduced as the coating thickness increased, but the anti-erosion property was improved. The emissivity test result indicated that the emissivity increased after the surface coating.