Thermal Stability of A Novel Ti-Si-C-N Superhard Nanocomposite Coating at Elevated Temperature
新型Ti-Si-C-N纳米复合超硬薄膜的高温热稳定性

Superhard nanocomposite Ti-Si-C-N coatings were deposited on substrate of high speed steel using an industrial pulsed d.c. plasma chemical vapor deposition set-up. Dependence of Si and C contents and annealing at elevated temperatures on the microstructure and hardness of Ti-Si-C-N coatings were investigated. Detailed microstructure examined by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) suggested that the Ti-Si-C-N coatings was a nanocomposite structure composed of nanocrystalline Ti(C,N) and amorphous carbon and Si3N4. And the crystalline size and microhardness of coatings showed high thermal stability even at 1000° C when Si and C contents were higher of 12.1 at.% Si, 32.9 at.% C. The possible origin of high thermal stability of superhard nanocomposite Ti-Si-C-N coatings is explained by spinodal decomposition that occurs during deposition.