Influence of Ytterbia Content on Residual Stress and Microstructure of Y₂O₃--ZrO₂ Thin Films Prepared by EB-PVD

Y₂O₃ stabilized ZrO₂ (YSZ) thin films with different Y₂O₃ molar contents (0, 3, 7, and 12mol%) are deposited on BK7 substrates by electron-beam evaporation technique. The effects of different Y₂O₃ contents on residual stresses and structures of YSZ thin films are studied. Residual stresses are investigated by means of two different techniques: the curvature measurement and x-ray diffraction method. It is found that the evolution of residual stresses of YSZ thin films by the two different methods is consistent. Residual stresses of films transform from compressive stress into tensile stress and the tensile stress increases monotonically with the increase of Y₂O₃ content. At the same time, the structures of these films change from the mixture of amorphous and monoclinic phases into high temperature cubic phase. The variations of residual stress correspond to the evolution of structures induced by adding of Y₂O₃ content.