Nitrided Silicon-Carbon Coatings Structure and Properties

Abstract

The paper considers structural and physicomechanical properties of silicon-carbon coatings deposited from a gaseous medium in doping with nitrogen ions. The analysis of the coatings by X-ray photoelectron spectroscopy shows that nitriding of silicon-carbon coatings promotes the formation of silicon nitride and compounds such as CNx and SixOyNz. A 1.5–2-fold increase in the content of sp2 -hybridized carbon and silicon carbide atoms is found to prevent silicon oxidation. Thermal annealing of the resulting silicon-carbon coatings increases the content of the graphite phase and silicon oxide.It is shown that doping of the working gas with nitrogen (Ar57 % + N43 %) leads to the formation of a more finely dispersed structure as compared to that when using argon only. During thermal annealing in air, the decreased carbon concentration and increased oxygen concentration can be observed due to silicon and carbon oxidation followed by desorption of carbon and oxygen compounds. In addition, annealing leads to nitrogen desorption from the coating. Nitriding of silicon-carbon coatings increases the dispersion of their structure, and heat-resistant compounds CNх, Si3N4 improve heat resistance and thermal stability of coatings, and increase microhardness and friction coefficient in friction units.