Crystallinity Influence on Mechanical Properties and Oxidation Resistance of Zirconium Silicon Nitride Thin Films

Zirconium silicon nitride thin films containing 8 at. % Si (Zr₃₉Si₈N₅₃) were codeposited via reactive magnetron sputtering at room temperature and at high substrate temperatures to produce amorphous and crystalline coatings. The main purpose was to investigate the dominant factor that determines the mechanical and thermal properties for these thin films: the crystallinity or the silicon content. Samples were characterized by RBS, SEM-FEG, GIXRD, nanohardness, and high-temperature oxidation. Crystalline Zr₃₉Si₈N₅₃ samples exhibited changes in preference grown orientation and reduction in crystallite size when compared to Zr₄₆Si₂N₅₂ samples (used for comparative purposes). These structural modifications caused a hardness value increase superior to 35% when compared to amorphous Zr₃₉Si₈N₅₃ samples, confirming the direct influence of crystallization on this mechanical property. All crystalline samples failed under high temperature tests, whereas only amorphous Zr₃₉Si₈N₅₃ samples demonstrated resistance to oxidation at 600 °C, indicating that a high silicon content combined with an amorphous structure plays a primary role for improving the oxidation resistance in Zr-Si-N thin films.