二硫化モリブデンスパッタ膜の大気中における摩擦摩耗特性に及ぼす硫黄対モリブデン組成比の影響

It has been known that molybdenum disulfide exists as a monophase in the S/Mo composition ratio range from about 1.94 to 2.25. In this study, sputtered molybdenum disulfide films having S/Mo ratio from 1.96 to 2.25 have been prepared on surface of JIS SUS440C rollers for cross roller bearings by applying the positive voltages ranging from 0 to 60 V to rollers. Friction coefficient and wear life of molybdenum disulfide films have been investigated by friction test conducted in air atmosphere of 10 % relative humidity. It is found that better lubricating performance which means longer wear life and lower friction coefficient was obtained in the films having S/Mo ratio from 2.06 to 2.15 near the center of the S/Mo composition ratio range of molybdenum disulfide. On the other hand, sudden drop of lubricating performance were appeared near both limit values of the composition ratio range.