Study On Friction And Wear Properties Of PTFE Matrix Composites In Humid Conditions

With the rapid development of tribology in aerospace high-tech and marine exploration,the tribological problem in terminal condition is more and more urgent to be solved.China has a vast territory,and its geographical conditions and climate types are complex and diverse,so the humidity of different geographical environments varies greatly,and the humidity in the same region varies from season to season.Because of the corrosive effect of water vapor on metal materials,a large number of polymer composites with excellent properties have been widely used in humid environment and water environment,gradually realizing “substituting plastic for steel”.Therefore,it is of great practical and theoretical significance to study the tribological properties of polymer composites in different humidity environments.In this experiment,three influence factors including the quality percentage of a two kinds additives and environment relative humidity percentage on moisture absorption?mechanical properties and tribological performance of PTFE matrix composites which use PTFE as the experimental matrix and use nano-lanthanum oxide and nano-serpentine as additive in different humidity environments are studied systematically.Using the Uniform Design method,the experimental scheme of 10 groups of composite materials was obtained,and PTFE composite materials with different levels were prepared according to the experimental scheme,mechanical properties and tribological properties were tested under different wet conditions.Multivariate linear regression was performed for the experimental data,and the corresponding regression model was obtained and the feasibility was verified.Based on the above results,the tribological properties of PTFE composite materials under different working conditions(contacting load and sliding speed)were further explored.The surface topography of composite materials and their metal splices were evaluated by SEM,and their frictional wear mechanism was analyzed in different humid environments.The experimental results show that,among the three influencing factors,nanoserpentine has the greatest influence on the hygroscopicity,the hardness and tensilestrength of PTFE matrix composites,nano-lanthanum oxide has the greatest influence on the friction coefficient and wear rate of PTFE matrix composites.The environmental relative humidity has the least influence on the above performance.Using MATLAB to optimize the equation of the regression equation,the experimental scheme of comprehensive performance of PTFE matrix composite materials was determined by comparison.It is concluded that that wear mechanism of PTFE-based composites gradually change from adhesive wear and cut wear to abrasive grain abrasion with the filling content increaing,the wear form of the above PTFE matrix composites is undergoing a transition period,when the relative humidity of the environment is 43%,the wear rate of the composite material is the least,indicating that the moderate degree of environmental humidity plays a major role in lubrication.Relative to the contact load,the influence of sliding velocity on the tribological performance of PTFE matrix composites is greater,The experimental results show that high load and low speed are the best applicable conditions for the composite.