Anti-oxidant mechanism of TiAlN/SiN decorative films on borosilicate glass by magnetron sputtering

Abstract

The black TiAlN decorative film was prepared on the borosilicate glass by the magnetron sputtering in equipment with multiple vacuum chambers. The transparent SiN protective layer was deposited on the surface of the TiAlN film to keep the black color invariant at the high temperature. The structure of the TiAlN/SiN film was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The coating adhesion was measured by scratch tester. The TiAlN film has a columnar crystal structure with a thickness of 200 nm, and the top SiN layer is amorphous with a thickness of 100 nm. The coated borosilicate glass with the TiAlN/SiN films still retains the black color after oxidation at 600 °C in atmosphere. While the oxidation temperature elevates to 700 °C, the color of the TiAlN/SiN films begins to change. The top SiN layer plays a role as the barrier against oxygen diffusion into the inner TiAlN layer. The thin self-formed aluminum oxide layer was generated on the surface of the SiN layer and it contributes to the improvement of anti-oxidant property of the inner TiAlN layer. However, the thick self-formed aluminum oxide layer leads to the color change of the black TiAlN film. The thermal oxidation benefits the improvement of the adhesion for the TiAlN/SiN films with glass substrate.