フィルタードアークデポジション法により成膜された炭素系硬質薄膜の摩擦摩耗特性に及ぼすTaの影響

抄録

Low friction and high wear resistance without lubricant is desired thinking of the widespread of friction condition. DLC(Diamond like carbon) coating is one of the material to obtain these properties. Among them, Ta-doped carbon nitride (CNx:Ta) coating is the most promising material, because it showed ultra-low friction (μ<0.01) in dry air. But the hardness of conventional CNx:Ta coating in our laboratory was only 1.6-11.3 GPa of nano-indentation hardness, and we need to improve the hardness for improving wear resistance. For the deposition of high hardness CNx:Ta coatings, we developed a dynamic mixing deposition method combining the filtered arc deposition system, nitrogen ion beam source and tantalum arc plasma gun. We deposited four kinds of DLC coatings, ta-C, ta-CNx, ta-C:Ta and ta-CNx:Ta. Nano-indentation result gave the hardness from 39.87(ta-CNx:Ta) to 44.98 GPa(ta-C). Friction coefficients of these coatings were same at the test with normal load of 1.0 N, but it varied at the test with normal load of 5.0 N, from 0.365 to 0.062. Also the wear differed in the test with normal load of 1.0 N, ta-C and ta-CNx:Ta coatings didn't peel off while ta-CNx and ta-C:Ta coatings peeled off. In order to know the effect of transfer layer on the friction coefficient, we did EDS analysis. The result showed that transfer layer of low friction coatings had more carbon and less oxygen than that of high friction coatings.