高湿窒素ガス環境下における窒化炭素膜の低摩擦発現

抄録

In this study, friction coefficient of 0.018 in averaged value could be achieved under humid nitrogen gas condition (0.5-40 %RH) with frictional pair of amorphous carbon nitride (CN_X) coatings. The coatings investigated were deposited onto Si₃N₄ ball and disk substrates by ion beam mixing (IBM) method. We performed friction tests of CN_X/CN_X under nitrogen gas condition. When CN_X-coated Si₃N₄ disk is rubbed by Si₃N₄ ball under ambient air and then the ball was changed to CN_X-coated one, friction coefficient of 0.019 in averaged value was achieved at the end of friction tests under 0.4 N load conditions. We investigated further concerning humidity and load dependence on friction properties, and finally we could find that friction properties are classified into three types in relation to friction coefficient and friction profile (TypeI; Stable friction coefficient µ_s is over 0.05, TypeII; Friction coefficient increases rapidly just after start of friction test but it dropped out and µ_s reached below 0.05, TypeIII; Friction coefficient is below 0.05 from the beginning). In case of TypeIII, friction coefficient less than 0.02 maintained with gradual increase of relative humidity.