稀土及制备工艺对PTFE三层复合材料性能的影响

发布时间：2018-04-18 01:25

本文选题：PTFE + 三层复合材料　；参考：《合肥工业大学》2015年硕士论文

【摘要】：工业科技的进步发展对滑动支承制品不断提出更苛刻的性能要求,PTFE三层复合材料作为卷制滑动支承制品的原材料之一,对其性能进行改进是必要的。长久以来,针对PTFE三层复合材料的填充改性研究已经做得非常深入了,但是关于稀土元素添加改性的研究不多。在此背景下,本课题以稀土作为改性原料,制备了一系列稀土改性PTFE三层复合材料。同时,采用不同的制备工艺制备了PTFE三层复合材料。在HDM-20端面摩擦磨损试验机上,分别模拟了干摩擦、油润滑工况条件进行了摩擦磨损实验。利用光学显微镜和扫描电镜对试样磨损表面进行了观测,并对实验结果进行了分析。稀土改性的研究结果表明：经稀土改性的复合材料能够在摩擦面形成光滑致密的铅、二硫化钼保护膜,极大地改善了复合材料耐磨性；稀土改性能降低聚四氟乙烯的热膨胀系数,从而减小了复合材料中各组分热性能的差异,减少了复合材料龟裂纹的产生,并阻止了裂纹的扩散；以卤化物溶液的形式进行改性能够使稀土分布得更均匀,从而获得更好的改性效果。稀土单独改性比混合改性获得更好的改性效果,且稀土镧、铈含量分别为0.75%、1%时,稀土单独改性的PTFE三层复合材料分别获得最好的改性效果。在制备工艺的研究中,得出如下结论：铜粉板的目数、复合工艺、减摩塑料层的厚度都影响着制备的三层复合材料的性能。随着铜粉目数的增大,制备的三层复合材料的表层减摩塑料层与中间烧结层之间的结合力降低。但较小目数的铜粉板易引起表面减摩层的橘皮现象,加重材料的疲劳磨损；干湿法制备的复合材料容易在摩擦表面上形成覆盖均匀的铅保护膜,较好的保护了PTFE基体材料,使得干湿法制备的复合材料具备更好的耐磨性；较厚的减摩层易积聚摩擦热,加剧了PTFE的蠕变,从而降低了材料的耐磨性。但较薄的减摩层限制了材料的使用极限。本课题通过对稀土改性PTFE三层复合材料摩擦学性能的研究及配方的优化设计分析,和对制备工艺中影响PTFE三层复合材料性能的关键因素研究,在产品性能的提高和制备工艺技术的优化方面取得了有益的成果,对行业生产技术的进步具有一定的参考实用价值。
[Abstract]:With the development of industrial science and technology, it is necessary to improve the performance of PTFE three-layer composite material as one of the raw materials for rolling sliding support products.For a long time, the research on the filling modification of PTFE three-layer composites has been very thorough, but the research on rare earth element modification is rare.Under this background, a series of rare earth modified PTFE three-layer composites were prepared.At the same time, PTFE three-layer composites were prepared by different preparation processes.The friction and wear experiments of dry friction and oil lubrication were carried out on the HDM-20 end face friction and wear tester.The wear surface of the sample was observed by optical microscope and scanning electron microscope, and the experimental results were analyzed.The results of rare earth modification show that the composites modified by rare earth can form smooth and compact lead and molybdenum disulfide protective film on the friction surface, which greatly improves the wear resistance of the composites.The rare earth modification can reduce the thermal expansion coefficient of PTFE, reduce the difference of the thermal properties of each component in the composite, reduce the crack generation of the composite turtle, and prevent the crack diffusion.The modification of rare earth in the form of halide solution can make the distribution of rare earth more uniform and obtain better modification effect.The results show that the rare earth modification alone is better than the mixed modification, and the rare earth lanthanum and cerium contents are 0.75 and 0.75 respectively. When the rare earth alone modifies the PTFE three-layer composite, the best modification effect is obtained.In the study of the preparation process, the following conclusions are drawn: the number of copper powder plates, the composite process and the thickness of antifriction plastic layer all affect the properties of the three-layer composite material.With the increase of copper mesh number, the adhesion between the surface antifriction plastic layer and the intermediate sintering layer of the three-layer composite is decreased.However, the copper powder plate with smaller number of particles can easily cause the orange peel phenomenon in the antifriction layer on the surface and aggravate the fatigue wear of the material. The composite prepared by the dry and wet method can easily form a uniform lead protective film on the friction surface, which can better protect the PTFE matrix material.The composite prepared by dry and wet method has better wear resistance, and the thick antifriction layer is easy to accumulate friction heat, which intensifies the creep of PTFE, thus reducing the wear resistance of the material.However, the use limit of the material is limited by the thin antifriction layer.In this paper, the tribological properties of PTFE three-layer composites modified by rare earth and the optimization design of the formula are studied, and the key factors affecting the properties of PTFE three-layer composites in the preparation process are also studied.Good results have been obtained in improving the product performance and optimizing the preparation technology. It has certain reference and practical value for the progress of production technology in the industry.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ325.4;TB33

【参考文献】