Study On Carbon Nanomaterials As Lubricating Oil Additives

The combination of different dimensions of carbon nanomaterials exhibits excellent lubricating property,it can significantly enhance the enhancement friction reduction and anti-wear properties of lubricating oil.However,the single preparation of carbon nanomaterials suffer from drawbacks such as long preparation period and high economic cost,and it is difficult to solve the dispersion stability problem due to different preparation processes.In this paper,two-dimensional nanographene sheets and zero-dimensional amorphous spherical carbon mixed carbon nanomaterials were prepared by using new type of electric arc furnace.The dispersion stability of carbon nanomaterials was improved by using the vacuum impregnation method,and it was used as lubricant additives to improve enhancement friction reduction and anti-wear properties of lubricating oil.The carbon nanomaterials were prepared by using electric arc furnace and characterized by TEM,TG,BET and porosimeter.It was found that carbon nanomaterials consist of nanographene sheets and amorphous spherical carbon.The specific surface area,the average pore diameter,and the total pore volume of carbon nanomaterials were as follows:123.150 m~2/g,22.144 nm,0.606 cm~3/g.The diameter and the number of layers of the nanographene sheet were as follows:100-200 nm,4-8 layers,and the diameter of amorphous spherical carbon nanoparticles is about 10-50 nm.The content of amorphous spherical carbon nanoparticles is11.35%,and the rest is attributed to nanographene sheet.Dissolving carbon nanomaterials with different dispersing agents prepared carbon nanomaterials lubricating oils with different dispersing agents.The dispersion stability of dispersant was tested by static sedimentation method,and the optimum dispersant was selected.The influences of the amount of optimum dispersant on the viscosity of the lubricating oil was tested by viscometer.The results demonstrated that the high molecular weight succinimide dispersant(HK11)exhibited good dispersion performance,the viscosity of the lubricating oil increased to 110.90 mm~2/s with an increase of the addition of HK11 to 4 wt.%,which exceeded the viscosity of the 500SN base oil used in the range of 90-110 mm~2/s.Different HK11concentration modification of carbon nanomaterials as lubricant additives were prepared by vacuum impregnation method.The dispersion stability was tested by static sedimentation and centrifugal absorbance,and it suggested that the modification of carbon nanomaterials as lubricant additives prepared by 0.03 g/ml HK11 dispersant solution showed the best dispersion stability.TG,FT-IR,XPS and Raman results indicated that the surface of the modification of carbon nanomaterials as lubricant additives adsorbed HK11 dispersant.The modification of carbon nanomaterials as lubricant additives was added into base oil with different addition amount.The influences of the modification of carbon nanomaterial on the viscosity of the lubricating oil was tested by viscometer and a four-ball machine.The results showed that the modification of carbon nanomaterials additives had little effect on the viscosity of the lubricating oil,and the viscosity of the lubricating oil increased 2.52%with an increase of the addition of additive to 0.09 wt.%,which was in accordance with the viscosity range of the 500SN base oil Subsequently,the average friction coefficient decreased 27.73%on average with the addition of the modification of carbon nanomaterials to 500SN base oil.The average friction coefficient was 0.078 with the addition of the modification of carbon nanomaterials at an optimal content of 0.025 wt.%,which decreased 34.45%,and the diameter of the wear spot was 0.582 mm,which decreased 3.64%.It was indicated that the modification of carbon nanomaterials lubricating oil additives exhibited excellent lubricating performance.0.025 wt.%of the modification of carbon nanomaterials additives were added into the shell commodity oil 15w-40.The anti-wear effect of modification of carbon nanomaterials additives in commercial oil was studied by four-ball friction and wear test.The results showed that the diameter of the wear spot decreased from 0.368 mm to 0.342 mm,which was reduced7.06%,it was attributed to improve the anti-wear properties of commercial oils.