Tribochemical effect of impurities in zinc dialkyldithiophosphate in engine oil

Abstract

Institute, Hefei Tr i b oc h e m i c a I Effect of I m p u r i t i e s in Zinc Dialkyldithiophosphate in Engine OilThis study deals with the effects of alcohols and ketones, two substances usually found in commercial zinc dialkyldithiophosphate (ZDDP), on the tribological behaviour of ZDDF! Experimental results show that two alcohol and ketone compounds, namely 2-ethylhexanol and methyl isopropyl ketone, respectively, have a n influence on the lubricity, wear resistance, and friction-reducing properties of ZDDF! 2-Ethylhexanol can increase the extreme-pressure properties of ZDDP (the loadcarrying capacity of a lubricating oil being enhanced from 710 to over 1100 N). At the same time, the alcohol can also improve the wear resistance of ZDDP However, this alcohol is detrimental to the antifriction properties of ZDDP, the friction coefficient of a lubricating oil being increased from 0.0919 to 0.1010. The antioxidative ability of ZDDP is weakened to some extent. The presence of a ketone, with a carbonyl group, greatly decreases the load-carrying capacity of ZDDP, which goes down from 710 N to 597.8 N on the addition of 1.5 wt.% methyl isopropyl ketone to ZDDF! The mechanisms of the influence of the alcohol and ketone on ZDDP are also investigated.Abstract alcohol, ketone, tribochemical performance, ZDDP, impurity

Current Knowledge on Friction, Lubrication, and Wear of Ethanol-Fuelled Engines—A Review

“…Another relevant point to be addressed is that one of the raw materials used to produce ZDDP is alcohol, meaning that some alcohol is unavoidably retained in commercial ZDDP during industrial production. Hu, et al [57] explored the effects of alcohol on ZDDP additives in engine oil, reporting that alcohol increased its load-carrying capacity. They attributed this to the adhesion of polar hydroxyl groups on the metal surface and formation a protective film, although no evidence for this was provided.…”

Preparation and tribological properties of the N‐containing heterocyclic borate esters and Cu microparticles as lubricant additives in base oil

“…However, conventional lubricant additives like zinc alkyl dithiophosphates possess considerable advantage, such as oxidation resistance, corrosion and abrasion resistance, and are widely used in lubrication area . Since sulfur and phosphorus usually cause catalyst poisoning and the zinc ion can produce chemical corrosion, there is a growing trend to develop additives with zero or low sulfur and phosphorus content (low SAPs or SAPs free). As a result, the traditional lubricating oil additives are facing great challenges, and the demands of green lubricating oil additives are growing when the environmental problems are more and more serious .…”