| Polytetrafluoroethylene(PTFE) fabric self-lubricating composite materials is a new type of solid self-lubricating material, PTFE fabric materials not only retain the low friction coefficient, but also has high mechanical strength. As a lubricating layer between the inner and outer rings of spherical plain bearings,they are widely used in the aerospace, automotive, heavy machinery and other fields.In this paper, preparation and development of PTFE woven fabric are discussed.The author choose the polytetrafluoroethylene(PTFE) fibers and the aramid fiber 1414(Kevlar) as raw material, weave the PTFE fabric by using the knitting machine, after the surface treatment in sodium-naphthalene complex liquid and use phenolic-epoxy resin to adhesive the PTFE fiber fabric and 45 steel. By the friction and wear testing machine, the friction coefficient and the wear are obtainable, which can help researching the influence of PTFE fiber content and surface treatment on tribological properties of composites. The scanning electron microscopy can be used to characterize the morphology of the surface friction and analysis the friction mechanism. After all, compared the PTFE fabric with the finished product to find the difference between them.Tests showed that sodium-naphthalene complex liquid surface treatment can deprive F element from surface of PTFE fabric, it enhanced the adhesion strength between the PTFE fabric and the metal, but the properties of PTFE fabric to a certain extent was reduced as the same time. And the shorter the surface treatment time is the less the low friction coefficient properties lost. And the sodium-naphthalene complex solution had little effect to aramid fibers and Kevlar fibers. the samples which in the the sodium-naphthalene complex solution for 5min, had more wear debris on friction surface, occurred abrasive wear.the higher PTFE fiber content the fabric had, the lower the friction coefficient was. For the fabric of the PTFE fiber content was 30%,as the rotational speed of the friction was rasing, the coefficient of friction was higher, and For it was 80%on the contrary, the higher the rotational speed of friction, the lower the coefficient of friction. the sample which PTFE fiber content was 80%, the rotational speed of friction was 400r/min or 500r/min,has the lower friction coefficient as 0.16.However, the lower the friction coefficient, the greater the wear amount, the sample which PTFE fiber content was 30%, the rotational speed of friction was 100r/min,has the a minimum wear amount as 9.6mg. the friction surface of the sample is more smooth, PTFE fibers mainly adhesive wear.For the two finished fabric due to the higher density of the fabric’s weave, reducing wear and abrasion resistance are both better. the fabric friction coefficient of PTFE/ Nomex fabric woven closed with PTFE fiber content of 80%, but the amount of wear was more less. PTFE fabric wear amount is large, but the coefficient of friction was lowest. After surface treatment in sodium-naphthalene complex liquid for 30 second the friction coefficient and the wear of finished product fabric volume increased. there was a friction surface rendering more complete with fine grinding marks and scaly areas. |
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