Study On The Properties Of Multi-scale Tribological Materials

In this thesis, we mainly studied the tribological materials of the relationshipbetween the molecular structure and tribological performance. The56kinds of fattyacid ester compounds as well as ultra high molecular weight polyethylene(UHMWPE) modified by different concentration of15kinds of inorganiccompound were investigated by quantitative structure tribo-abliltyrelationship(QSTR) model. The major conclusions of this thesis are as follows:1. Loading capacity of octoate base oils were related to the number of estergroups. In the case of the same ester groups, the more number of ester groups inmolecules, the higher loading capacity the material had. During the long frictiontest under294N, the wear scar diameter(WSD) and coefficient of firction(COF) ofbutyloctanoat,1,2-propylene glycol dioctanoate,1,4-octylic acid butyl ester werelower than trioctanoin and pentaerythritol tetraoctanoate, it proved that anti-wearand friction-reducing of octoates were concerned with ester molecule structure andthe number of ester groups.2. The long carbon chain fatty acid esters firction properties was studied byfour ball machine test, the loading capacity of esters significantly associated withthe increasing of carbon chain of fatty acids. Under the low load (196N-294N), theWSD and COF of fatty acid triglycerides decreased with the increasing of carbonchain of fatty acid, the friction-reducing effect of long carbon chain fatty acidtriglycerides were more stable than medium long carbon chain fatty acidtriglycerides. Under the moderate load (392N-490N), fatty acid triglycerides can beseized more easily than fatty acid butanediol esters, long carbon chain fatty acidtriglycerides are easier seizure than medium long carbon chain fatty acidtriglycerides under high temperature. Under the high load (588N), fatty acidtriglycerides were easy to be seized, the tribology properties of fatty acidbutanediol esters are superior to the fatty acid triglycerides.3. In the study of56kinds of lubricating esters in the QSTR, the estermolecules having the same number of ester groups, the branched alkyl chain longer,the better the performance of the friction-reducing was. Through the use of esterstructural parameters and tribological performance parameters establishedBPNN-QSTR model, q2was used to characterize the model predictive accuracy, R2was employed as robust indicators, the findings showed that the models had createdgood predictive ability.4. Using different concentrations of inorganic modified UHMWPE, thefriction-reducing performance of modified UHMWPE with5%WS2,10%WS2,15%ZrO2and5%AlN were superior to that of pure UHMWPE; the anti-wearperformance of modified UHMWPE with5%ZnO,5%Ag2S,10%Ag2S,15%Al2O3 and10%SiO2were better than that of pure UHMWPE. The small molecular dipolemoment and the large volume of inorganic compounds can enhance thefriction-reducing properties of modified UHMWPE; the small dipole moment andthe large entropy will improve the anti-wear performance of modified UHMWPE.