For reducing the frictional losses on the sliding surfaces of mounting parts and improving the wear resistance in order to extend the life of
the component, diamond–like carbon (DLC) film coating has been considered, in recent years. However, reduction of the long processing time
involved is desirable for mass production. For achieving this, the effect of mixing hydrocarbon gas and hydrogen gas in the deposition process
is compared, and the differences in the resulting DLC films are determined in this study. DLC films are deposited on Si wafers through radio
frequency plasma chemical vapor deposition (RF–PECVD), with a mixture of methane gas and hydrogen (dilution gas) as the raw material. In
addition, DLC films are prepared by mixing acetylene gas with hydrogen gas for comparison, and the effect of the hydrogen gas mixture on the
deposition rate, composition, and hardness of the films is confirmed. When hydrogen gas is mixed with methane gas, the deposition rate
increases with the increase in the ratio of hydrogen gas in the raw material, and the percentage of sp3 bonds increases; however, the hardness
and elastic modulus decrease. Furthermore, the adhesiveness deteriorates with the increase in the hydrogen gas
ratio.