The Preparation and Microstructure of Nanocrystal 3C-SiC/ZrO₂ Bilayer Films.

The nanocrystal 3C-SiC/ZrO₂ bilayer films that could be used as the protective coatings of zirconium alloy fuel cladding were prepared on a single-crystal Si substrate. The corresponding nanocrystal 3C-SiC film and nanocrystal ZrO₂ film were also dividedly synthesized. The microstructure of nanocrystal films was analyzed by grazing incidence X-ray diffraction (GIXRD) and cross-sectional transmission electron microscopy (TEM). The 3C-SiC film with less than 30 nm crystal size was synthesized by Plasma Enhanced Chemical Vapor Deposition (PECVD) and annealing. The corresponding formation mechanism of some impurities in SiC film was analyzed and discussed. An amorphous Zr layer about 600 nm in width was first deposited by magnetron sputtering and then oxidized to form a nanocrystal ZrO₂ layer during the annealing process. The interface characteristics of 3C-SiC/ZrO₂ bilayer films prepared by two different processes were obviously different. SiZr and SiO₂ compounds were formed at the interface of 3C-SiC/ZrO₂ bilayer films. A corrosion test of 3C-SiC/ZrO₂ bilayer films was conducted to qualitatively analyze the surface corrosion resistance and the binding force of the interface.