Tribological Study of High Performance Bio-Lubricants Enhanced with Ionic Liquids for Use in Wind Turbines.

摘要

Wind power is one of the fastest growing power sources worldwide. Large installations of wind power generation are prominent in Asia, Europe and the United States. The gear boxes and bearings of large wind turbines continue to be huge liabilities and fail well short of their 20 year design life. These mechanical failures impose long and expensive repairs. The reliability of wind turbine drive systems may be improved through advances in lubrication. Furthermore, increasing environmental regulations and public policy have ushered in the need for development and implementation of environmentally friendly lubricants. Over the past decade, ionic liquids have emerged as high performance fluids and lubricant additives due to their unique characteristics. Ionic liquids have the ability to form stable ordered layers in liquid state and have been shown to have the potential to be used as high-performance lubricants; however, most of the ionic liquids currently used in lubrication are composed of halogen-containing anions. It is well known that these anions will decompose in presence of water, liberating highly toxic and corrosive species. There is an urgent need to design halogen-free and hydrolytically stable ionic liquids to avoid this negative effect. In this study, the tribological behavior of two phosphonium-based ionic liquids, is investigated as additives of a commercially available bio-oil in steel-steel contact. One of the ionic liquids is halogen-free and will be compared to an ionic liquid that contains halogens. Bio-oil and ionic liquid mixtures containing 0.5 ,1 and 2.5 wt.% of both ionic liquids are studied using a pin on disk tribometer and compared to a commercially available, fully formulated lubricant over a range of three speeds. Results showed, that under the fastest speed tested, At the optimal concentration of 1% [THTDP][NTf2], a wear reduction of 74% was achieved with respect to the base Biotelex. A 66% reduction was observed with respect to the Mobilgear. Similarly, the optimal concentration of 2.5% [THTDP][Phos] displayed a 68% wear reduction compared to the base Biotelex and a 58% reduction compared to the Mobilgear.