Preparation of fine-grained MgO and Gd2O3 stabilized ZrO2 thin films by electron beam physical vapor deposition co-evaporation

Abstract

Thin films of ZrO2 doped with MgO and Gd2O3, 1–1.5 μm in thickness are formed onto nickel substrates by reactive thermal evaporation using a dual-hearth electron gun. X-ray diffraction patterns of the deposits show changes in the crystallographic structure and average particle size as a function of the dopant content. A mixture of monoclinic and tetragonal phases gradually disappears to become a single cubic phase with increasing dopant molar fraction. The average crystallite size deduced from diffraction line broadening decreases as the dopant content increases. This observation is strongly confirmed by scanning electron micrographs which reveal a smooth surface topography. Fine-grained materials obtained here are interpreted in terms of high nucleation rate and kinetically limited grain growth. It appears that composition, crystallographic structure, and microstructure relations are of paramount importance in ZrO2-based films prepared by electron-beam evaporation.