Synthesis And Research On The Property Of Lubricant Additive

From the point of view of energy saving and raise economic benefit, we usedmolybdenum and grapite mineral to prepare composited lubricant additive, which wasdomestically rich. Six kinds of organic molybdenum/modified graphite composited lubricantadditive have been prepared in this work. The performance of six kinds of lubricant additiveswas studied, and the specific results were listed as follows:Firstly, three kinds of oil-souble organic molybdenum, MoDTP, MoDTC and MoOEA,were synthesized and analysised by FTIR. The synthesis process of MoDTP and MoDTC hadbeen mature, while the synthesis process of MoOEA had not been reported. Optimizationconditions for synthesizing MoOEA were oleic acid di-ethylanide: sodium molybdate=1:0.5,DMF as promote agents, and pH=5.Secondly, expanded graphite (EG) was prepared by method oxidised with ammoniumpersulfate?and its dispersibility in base oil was taken as the evaluation factor. The resultsshowed that the larger the expansion volume was, the better in dispersibility. So expansionvolume was taken as evaluation factor in preparing EG. Optimization condition for preparingEG was1:0.75:11for the ratio of expanded graphite: ammonium persulfate: sulfuric. Underthe condition, the expansion volume reached200mL/g when reaction time lasted30min. Thegrapheme was prepared by Hummer's Method. And it was found that the dispersity ofgrapheme (GE) was good in the base oil.Thirdly, the physicochemical quality of various materials prepared in this work wasstudied. These composited additives in liquid paraffin were of good solubility anddispersibility because liquid paraffin was a kind of mineral oil with low viscosity and contained a small amount of polar ingredient which finally increases solubility anddispersibility. The results showed that base oil containing organic molybdenum had higheroxidation stability; the organic molybdenum containing S and P raised corrosion on copper toa certain extent, but the corrosion would not happen while S and P were not contained inorganic molybdenum. When EG or GE was added, the corrosion of copper sheet would bealleviated because EG or GE forms protective film on the surface of copper sheet, whichimproved the corrosion resistance of base oil. Friction coefficient tended to be stable when a2%of organic molybdenum was added into base oil. Friction coefficient tended the minimumvalue when organic molybdenum (2%) and modified EG or GE (0.1%) were contained in thecomposited additives.Finally, the research on friction coefficient and wear scar diameter of the abovementioned additives was carried out by four-ball machine under different loads. Scarmorphology of samples ball was surveyed, and friction mechanism was briefly discussed. Theexperimental result showd that the coefficient of friction could effectively decrease underhigh and medium load with the organic molybdenum additive; when adding EG or GE,wearing of the ball surface could be mitigated, and the lubricating property of the oil wasfurther improved. Experimental results also showed that chemical reaction occured betweenorganic molybdenum compounds and contact surface in the process of friction. Thus MoO3,MoS2and boundary lubricating film composed of iron oxides were produced, and thelubricating film functioned well in anti-friction and anti-wear. EG and GE were of smallerdiameter, so they could quickly fill grooves on the surface weared and teared, and it furtherimproved the lubrication performance together with organic molybdenum additives.