Study On The Tribological Properties Of Ptfe-Based Composites Materials Sliding Pair Under Extreme Environment

Polytetrafluoroethylene(PTFE) is an excellent solid lubricating material, with low friction coefficient, good chemical stability. It also has excellent thermal stability and self-lubrication and a wide range of application. However, PTFE has poor wear resistance, low strength, poor thermal conductivity and ease to creep and other shortcomings, so limit the application of PTFE in practice. Need to be filled in order to make up for lack of performance. At home and foreign the reports on the modification of PTFE filled are many, however, most literature studied under vacuum or low-temperature of the single effect factors, and reports on PTFE composites under harsh conditions such as vacuum and low-temperature are few. In view of this, this article does the following works.Selecting the glass fiber significantly increased wear resistance, MoS2 beneficial formed transfer lubrication film and graphite of low friction coefficient as fillers. By the method of changing the type of filler, particle size and concentration, then after weighing, mechanical mixing, drying, cold forming, sintering and other steps, prepare a series of PTFE-based composites. Designing friction and wear tester, testing friction and wear properties of them under vacuum and low temperature environment, and friction and wear mechanisms were analyzed.Do tribological experiments of GF/PTFE composites, Gr/MoS2/PTFE composites and GF/Gr/MoS2/PTFE composites under vacuum and low-temperature environment. The results show that: for the GF/PTFE composites, with the GF particle size decreases, the friction coefficient decreases, with the decreases of particle size, the wear rate first reduced and then increased; with the increases of GF content, the friction coefficient increases, the wear rate first decreases and then increases. The friction coefficient of Gr/MoS2/PTFE composites decreases as the temperature decreases; with the load and speed increase, the friction coefficient decreases, wear rate increases; and its friction coefficient is much smaller than the GF/PTFE composites, its wear rate is larger than the GF/PTFE composites.The friction coefficient of GF/graphite/MoS2/PTFE composites also decreases with temperature decreases; the higher the vacuum, the greater friction coefficient; the quaternary composites maintain the wear resistance of GF/PTFE composites, but also reduce the friction coefficient. Final draw: when filled with 15% of 200-mesh GF, 3% of MoS2, 8% of graphite, the friction coefficient is lower, and wear rate is the lowest. The SEM results show that: Filling the appropriate content and size of the GF, with shallow furrows of worn surface, improves the hardness modulus and wear resistance of the composites, the adding of graphite and molybdenum disulfide promotes the formation of transfer film and reduces the friction coefficient, makes worn surface more smooth.