Tribological Properties Of Plant Leaf-surface Wax As Lubricant Additives And Simulation Analysis

With the increasingly severe environmental problems, environmentally friendly lubricant has attracted more attention of researchers around the world. But there are no studies on the plant leaf-surface wax as lubricant additives by now. So in this paper, Poly Alpha Olefin(PAO) and lithium grease were selected as base oil, and leaf-surface wax extracted from Ammopiptanthus mongolicus, Hoya carnosa (L.f.)R. Br, Solanum melongena and other seven kinds of plant leaves as additives to investigate their lubricating properties. The main conclusions are as follows.1. Leaf-surface wax extracted from Ammopiptanthus mongolicus, Hoya carnosa(L.f.)R. Br, Cedrus deodara(Roxb.) G. Don, Reaumuria soongorica, Solanum melongena and other leaf-surface wax possess excellent lubricating properties as lubricant additives. For steel-aluminum contact, Ammopiptanthus mongolicus, Hoya carnosa(L.f.)R.. Br, Cedrus deodara(Roxb.) G. Don, etc. can reduce friction and wear effectively, provide a good protection to the surface of the friction pair, which proves that they all possess good tribological properties. For steel-steel contact, Cedrus deodara(Roxb.) G. Don, Hoya carnosa(L.f.)R. Br, Allium fistulosum L.var. giganteum Makion, Ammopiptanthus mongolicus, Brassica oleracea L. and other additives can also reduce friction and wear effectively, showing excellent friction reduction and anti-wear properties. For steel-copper contact, Ammopiptanthus mongolicus, Reaumuria soongorica, Hoya carnosa(L.f.)R. Br, Cedrus deodara(Roxb.) G. Don and other several additives have good friction reduction properties. The main reason for plant additives excellent tribological properties, determined by XPS, is the formation of protective film mainly containing polymeric ester, metal oxides, hydroxides, carbonates and phosphate, which can effectively protect worn surface and greatly improve lubrication properties. So we can make a conclusion that plant-surface wax is excellent novel versatile environmentally friendly lubricant additives with good development and important research significance.2. The results of GC/MS for Ammopiptanthus mongolicus show that the main components of the wax are non-polar fraction and polar fraction. The latter mainly includes fatty acids, fatty alcohols, fatty ketones, esters and pentacyclic triterpene alcohol, etc., which play an important role in reducing friction and wear to protect the worn surface.3. ANSYS was used to simulate the wear process, analyze the stress distribution and predict the wear volume. The results suggest that the simulation curve and experimental curve can coincide perfectly.