潤滑油中におけるCN_x膜の超低摩擦現象の発現(機械要素,潤滑,工作,生産管理など)

抄録

Recent investigations have confirmed that CN_x (Carbon Nitride) coating showed superlow friction coefficient when it slid against a Si_3N_4 ball in N_2. However, superlow friction was not kept when it lubricated. It was considered that lubricant oil swept the transfer film. To clarify superlow fiction possibility of CN_x coating using under PAO (poly-alpha-olefins), we prepared 4 different friction pairs as (a) as-deposit CN_x vs. a Si_3N_4 ball, (b) as-deposit CN_x vs. CN_x transfer layer on a Si_3N_4 ball, (c) CN_x surface rubbed under N_2 blowing vs. a Si_3N_4 ball, and (d) CN_x surface rubbed under N_2 blowing vs. CN_x transfer layer on a Si_3N_4 ball. We investigated the effect of running-in, or to do the effect of CN_x transfer layer, on friction coefficient under PAO. In the case of using CN_x surface rubbed under N_2 blowing to friction test, the lowest friction coefficient was obtained approx. 0.017 in PAO. In order to know the differences of CN_x coatings' surface energy, which was before and afer rubbing under N_2 blowing, we measured contact angles of water and CH_2I_2 droplet on as-deposit CN_x and inside of wear track to calculate hydrogen bond component and dispersion force component. The CN_x coating after sliding under N_2 blowing indicated higher dispersion force component value than as-deposit CN_x. It seemed to be a hydrophobic surface. We assumed that the hydrophobicity made the CN_x low friction coefficient surface rather than as-deposit CN_x.