ALL libraries (COBIB.SI union bibliographic/catalogue database)
  • Comparison of the effects of the lubricant-molecule chain length and the viscosity on the friction and wear of diamond-like-carbon coatings and steel
    Velkavrh, Igor ; Kalin, Mitjan
    For steel contacts it is usual for the longer molecular chain lengths of saturated linear hydrocarbons and their acids and alcohols to reduce the coefficient of friction in the boundary-lubrication ... regime. However, the effect of these lubricant properties on DLC contacts is still unknown. Since the boundary- lubrication mechanisms between DLC coatings and conventional additives do not appear to be as effective as with metals, other potential mechanisms, even though based on weaker interactions or the oilʼs physical andrheological properties, may thus be very relevant. In this study we focus on the influence of the base oilʼs chain length and viscosity on the friction and wear in DLC/DLC contacts, and we compare this behaviour with conventional steel/steel contacts, using several simple linear hydrocarbons, i.e., alkanes, and complex branched hydrocarbons, i.e., polyalphaolefins. The results show that in both the steel/steel and DLC/DLC contacts the wear decreases with a longer molecular chain length and a higher viscosity of the oil. However, in DLC/DLC contacts the coefficient of friction increases when oil with a longer molecular chain length or a higher viscosity is used, and decreases with the lower oil viscosity and shorter chain lengths, which is just the opposite to conventional steel/steel behaviour. These results are analysed and discussed in view of lubricant cohesive energy, surface tension, shear strength, viscosity and chain length.
    Source: Tribology international. - ISSN 0301-679X (Vol. 50, 2012, str. 57-65)
    Type of material - article, component part
    Publish date - 2012
    Language - english
    COBISS.SI-ID - 12266267