DLC (Diamond-Like Carbon) films are being increasingly applied to various industrial products due to their low friction, wear resistance, small surface roughness, and chemical stability. Among these, ta-CNx (tetrahedral amorphous carbon nitride) films are particularly advantageous because they exhibit low friction and high wear resistance in lubricating oil. Such ta-CNx films have the advantage of a reduced friction coefficient with increasing nitrogen content, but at the same time, they face the challenge of a decrease in hardness. To solve this problem, this study aims to develop high-nitrogen-content ta-CNx films with high hardness and excellent wear resistance. The films were deposited using the GSC-FCVA (gas supplying cathode-filtered cathodic vacuum arc) method, which supplies nitrogen gas directly to the graphite target via a T-FAD system. By observing the arc plasma during deposition and evaluating the properties of the deposited ta-CNx films, the study attempts to propose and validate optimal deposition conditions. The results revealed that shortening the deposition time and increasing the substrate cooling time suppressed the reduction in hardness associated with increased nitrogen content in the ta-CNx films. Under the conditions of 10 seconds of carbon ion irradiation and 1500 seconds of cooling time without irradiation, a ta-CNx film with an N/C ratio of 13.5% and a hardness of approximately 35.1 GPa was obtained. Additionally, plasma observations showed that the GSC-FCVA method resulted in a higher proportion of C-N bonds compared to conventional deposition methods.
WAKITA et al. (Wed,) studied this question.