The polyalkylene glycol (PAG) lubricants are widely used as gear, bearing and compressor oils. Indeed, the base PAG oil can be used as additive in engine oil or transmission oil as well as compressor lubricant in refrigerant systems. They are designed to provide outstanding benefits in terms of efficiency, long oil life, and equipment protection. These fully synthetic lubricants were developed for use under operating conditions beyond the capabilities of other synthetic lubricants and mineral oils. Their low pour points ensure excellent low-temperature fluidity. On the other hand the main disadvantage of the PAG oils is the marked hygroscopicity, i.e. they absorb and bind moisture from the ambient air. In this paper the results from tribological testing of PAG oil featuring 46 cSt at 40°C with solid (graphene oxide) and liquid (ionic liquids) additives are proposed. Moreover, in this study the influence of the absorbed moisture from ambient air has been taken into account. Preliminary experiments with ball-on-flat setup by using reciprocatory tribometer have been carried out on the base oil PAG 46 blended with 1-Ethyl-3-methylimidazolium acetate or graphene oxide, alternatively. In this way the influence of each additive has been investigated. Based on this information the aim of this research is to test the hybrid formulations and to verify potential improvements on anti-friction and anti-wear PAG 46 behaviour in broad range of lubrication regimes. The experimental tests have been carried out by using rotational disc tribometer in ball-on-disc configuration. Additional experiments after samples exposure to ambient air and ensuing moisture absorption were executed. The results highlight that in most cases the absorbed moisture do not introduce detrimental effects on the tribological performances of the tested oil samples. Rather, water content reduces wear of the sliding steel surfaces in the whole testing spectrum and in many cases the frictional dissipation.
|Titolo:||TRIBOLOGICAL EFFECTIVENESS OF GRAPHENE OXIDE AND IONIC LIQUIDS IN PAG OIL: COULD ABSORBED WATER PLAY BENEFICIAL ROLE?|
|Data di pubblicazione:||2016|
|Appare nelle tipologie:||1.1.2 Articolo su rivista con ISSN|