聚苯酯填充聚四氟乙烯复合材料摩擦学行为研究

采用聚苯酯（Ekonol）、Ekonol／PAB纤维增强聚四氟乙烯（PTFE）制备利用转移膜润滑的摩擦副材料，并研究了两组材料在于摩擦条件下与9Cr18轴承钢对摩时的摩擦学性能；运用扫描电镜分析了两组材料磨损表面形貌和磨损机理。结果表明：随着Ekonol含量的增大，Ekonol填充PTFE复合材料的摩擦因数逐渐增大，当Ekonol质量分数超过25％时摩擦因数略有下降，磨损方式由以犁削磨损为主转变为以疲劳磨损为主；而Ekonol／PAB纤维填充门FE复合材料的摩擦因数，随Ekonol含量的增大而增大，磨损方式由以粘着磨损为主转变为以疲劳磨损为主。Ekonol／PAB纤维填充PTFE复合材料的摩擦学性能优于Ekonol填充PTFE复合材料。     

有机填料填充聚四氟乙烯复合材料摩擦学及力学性能

采用共混-冷压-烧结-整形的工艺制备有机物填充聚四氟乙烯(PTFE)复合材料,考察相同含量的不同有机填料对PTFE复合材料力学性能和摩擦学性能的影响。结果发现,加入有机填料后,复合材料的拉伸强度降低,但硬度和压缩强度均提高;有机填料有效地改善了PTFE复合材料的摩擦学性能,其中,质量分数15%聚苯酯填充的PTFE复合材料减摩效果最好,质量分数15%聚酰亚胺填充的PTFE复合材料的耐磨损性能最优。相比之下,质量分数15%芳纶填充的PTFE复合材料摩擦磨损性能及力学性能最好,其耐磨损性能较纯PTFE提高了近400倍,而摩擦因数仅为纯PTFE的84%。其原因在于芳纶的加入有效地改变了摩擦机制,能形成均匀连续的转移膜,进而降低了磨损。     

氧化石墨烯和纳米SiO2增强PTFE复合材料的摩擦磨损行为

为研究具有层状结构和球状结构的纳米填料之间的相互作用对聚四氟乙烯（PTFE）复合材料摩擦磨损行为的影响,采用冷冻干燥超声共混-冷压-热烧结法制备纳米二氧化硅（nano-SiO2）和氧化石墨烯（GO）填充改性PTFE复合材料。利用LSM-2R往复式摩擦磨损试验机测试干摩擦条件下nano-SiO2和GO复配改性PTFE复合材料的摩擦学性能,采用MicroXAM-800非接触式三维表面轮廓仪、扫描电子显微镜(SEM)和能谱仪(EDS)分析表征转移膜形貌、元素分布和磨痕表面三维形貌,从微观层面揭示nano-SiO2和GO的减摩机制。结果表明：单独填充nano-SiO2与GO均可改善PTFE复合材料的摩擦学特性,其中在较低添加量下,GO在提高PTFE耐磨性方面明显优于nano-SiO2;GO和nano-SiO2复配填充时存在协同效应,与单一填充相比进一步改善了复合材料的摩擦学性能;相比于纯PTFE,3%nano-SiO2/0.5%GO/PTFE复合材料的磨损率降低60.36%。机制分析表明,协同作用和均匀连续转移膜的形成是nano-SiO2和GO增强PTFE复合材料性能优异的主要原因。     

硫酸钙晶须填充PTFE复合材料的摩擦学性能研究

用硫酸钙晶须(CSW )填充改性聚四氟乙烯(MVE),采用模压成型工艺制备不同硫酸钙晶须含量的PTFE/CSW复合材料;利用摩擦磨损试验机研究硫酸钙晶须对PTFE/CSW复合材料摩擦学性能的影响,利用扫描电子显微镜对PM复合材料的磨损表面进行微观分析.结果表明:填充硫酸钙晶须提高PTFE复合材料的耐磨损性能,但复合材料的摩擦因数略高于纯PTFE;纯PTFE的磨损机制为黏着磨损,而PTFE/CSW复合材料的磨损机制为轻微磨粒磨损和黏着磨损共同作用.当硫酸钙晶须质量分数大于10%时,PTFE/CSW复合材料的磨损机制逐渐转变为严重的磨粒磨损.     

短玻璃纤维和石墨填充PTFE的摩擦磨损特性研究

利用自主研制的往复式摩擦试验机对短玻璃纤维(SGF)及石墨填充聚四氟乙烯(PTFE)复合材料的摩擦磨损特性进行了研究,探讨了共混材料对PTFE摩擦学性能的影响。利用扫描电子显微镜对材料的磨损表面进行了观察和分析。研究结果表明,短玻璃纤维有效提高了PTFE的承载能力,石墨的加入起到了减小摩擦的作用,在较高载荷下,短玻璃纤维和石墨填充的PTFE复合材料表现出优异的抗磨性能。     

表面改性硅灰石纤维填充PTFE复合材料的摩擦学性能

用KH550硅烷偶联剂表面改性的硅灰石纤维(WF)填充PTFE,在MPX-2000型磨损试验机上研究复合材料的摩擦磨损性能,并与经典的炭纤维(CF)填充PTFE复合材料进行比较。采用SEM对磨损面和对偶面进行分析。结果表明:较高载荷(200和300 N)下复合材料摩擦因数随WF含量变化的幅度不大,较稳定地维持在较低值;细小尺寸WF填充PTFE复合材料的耐磨性能较好,在WF质量分数为10%时,复合材料的磨损量只有相同含量CF填充PT-FE复合材料的81%;细小尺寸WF填充PTFE复合材料的磨损面较为平整,存在轻微黏着磨损,其对偶面转移膜平整光滑、结构致密;而CF/PTFE复合材料磨损面存在许多裸露和碎断的CF,犁削和磨粒磨损是主要的磨损形式。     

聚四氟乙烯纳米复合材料的制备及其力学和摩擦学性能

以添加表面活性剂的水为溶剂,采用溶剂混合法制备纳米 Al2 O3填充聚四氟乙烯（PTFE）复合材料,研究其力学性能和摩擦学性能,并与乙醇中分别制备纳米 Al2 O3填充 PTFE 复合材料进行比较。结果表明：在相同 Al2 O3填充比例下,水中制备的复合材料的拉伸强度和硬度要低于乙醇中制备的复合材料,而断裂伸长率却要高于乙醇中制备的复合材料。在200 N 和干摩擦条件下,当纳米 Al2 O3质量分数为1％～5％时,水中制备的复合材料的磨耗量要低于乙醇中制备的复合材料,并较纯 PTFE 磨耗量下降了1～2个数量级;且水中制备的复合材料的摩擦因数也要低于乙醇中制备的复合材料。复合材料磨痕处 SEM显示复合材料的磨损机制为黏着磨损和磨粒磨损。     

泥沙条件下改性复合材料减振降噪性能研究

为了改善水润滑轴承材料热塑性聚氨酯（TPU）的减振降噪性能,以TPU为基体、聚四氟乙烯（PTFE）为添加剂,通过物理共混的方式制备PTFE/TPU改性复合材料。在RTEC摩擦磨损实验机上模拟泥沙工况,对复合材料进行不同速度和载荷下的摩擦学试验,通过分析复合材料的力学性能、摩擦因数、表面形貌以及振动噪声行为,探讨其摩擦磨损规律与减振降噪性能。结果表明：复合材料的拉伸强度和邵氏硬度均随着PTFE含量的增加而先增加后降低,质量分数8%PTFE改性TPU复合材料表现出最好的力学性能;随着速度与载荷的增大,复合材料的摩擦因数逐渐增大,材料表面损伤、变形、剥落等严重损伤逐渐增多;与纯TPU相比,改性复合材料的摩擦磨损剧烈程度更低,摩擦因数的变化幅度较小且摩擦因数曲线相对光滑,材料微观表面的损伤更少;随着速度与载荷的增大,复合材料的振动响应与辐射噪声现象增大,振动与噪声信号的平均强度增大,频域上的频率分量增多,幅值分量增大,主频向高频转移;PTFE能够改善TPU的摩擦学性能,降低摩擦因数,同时赋予复合材料一定的减振降噪性能,并且效果在高速、高载荷下更为明显。     

PTFE基复合材料海水润滑下的摩擦学性能研究

研究碳纤维/聚四氟乙烯（CF/PTFE）、玻璃纤维/聚四氟乙烯（GF/PTFE）复合材料与氮化硅陶瓷配副在海水环境下的摩擦学性能与润滑机制,分析滑动速度对摩擦副海水润滑性能的影响规律。结果表明：在海水润滑条件下,随着滑动速度的增加,PTFE、CF/PTFE、GF/PTFE材料与Si3N4陶瓷配副时的摩擦学性能均有明显改善,摩擦因数与磨损率均呈显著降低的趋势,其中CF/PTFE复合材料表现出更为优异的摩擦学性能,在1 000 r/min滑动速度下摩擦因数低至0.026。磨损表面表征结果表明,在海水润滑条件下,PTFE基复合材料在摩擦过程中由于摩擦化学反应生成了润滑膜,可为摩擦副提供良好的润滑和减磨作用,从而减少摩擦磨损行为的发生。     

石墨填充聚四氟乙烯基复合材料的摩擦学性能

为了研制PTFE基粘弹-摩擦型阻尼材料,采用机械共混-冷压成型-烧结的工艺制备了石墨、聚苯硫醚、聚醚醚酮混合填充PTFE基复合材料,利用环-块式磨损试验机,在干摩擦条件下考察了复合材料的摩擦学性能,并用扫描电镜观察了磨损表面形貌,研究了复合材料的磨损机制。结果表明:PTFE含量不同的复合材料,随石墨填充量的增大,摩擦因数和磨损率的变化趋势不同,磨损主要由犁削、粘着和疲劳剥落中的一种或几种引起;适当配比的PTFE基复合材料具有较好的摩擦阻尼性能,能够满足粘弹-摩擦阻尼材料的要求。     

聚四氟乙烯碳纤维增强双马来酰亚胺复合材料的摩擦学性能

研究了不同含量PTFE碳纤维增强双马来酰亚胺复合材料的力学和摩擦学性能,并分析了在干摩擦和水润滑条件下的磨损表面形貌和磨损机制。结果表明:添加质量分数10%~15%PTFE的复合材料体系机械性能最佳,随PTFE含量的增加,复合材料的摩擦因数下降,而磨损率呈上升趋势。水润滑下,摩擦因数和磨损率比干摩擦下都有相应的降低。干摩擦下,材料的磨损主要以塑性变形、微观破裂及破碎为主;水润滑下,这一机制明显减弱,主要表现为微切削形态。     

Tribological Behavior of Carbon-Nanotube-Filled PTFE Composites

Carbon nanotube/polytetrafluoroethylene (CNT/PTFE) composites with different volume fractions were prepared and their friction and wear properties were investigated using a ring-on-block under dry conditions. It was found that CNTs signifi-cantly increased the wear resistance of PTFE composites and decreased their coefficient of friction. PTFE composites with 15–20 vol.% CNTs exhibited very high wear resistance. The significant improvements in the tribological properties of CNT/PTFE composites are attributed to the super-strong mechanical properties and the very high aspect ratio of CNTs. The CNTs greatly reinforce the structure of the PTFE-based composites and thereby greatly reduce the adhesive and plough wear of CNT/PTFE composites. The CNTs are released from the composite during sliding and transferred to the interface of the friction couples. They thus serve as spacers, preventing direct contact between the mating surfaces and thereby reducing both wear rate and friction coefficient.     

纳米ZnO填充的PTFE基复合材料摩擦学性能研究

得胜０００型摩擦磨损试验机研究了不同体积含量的纳米氧化锌（ＺｎＯ）填充的ＰＴＦＥ基复合材料在于摩擦条件下与不风对摩时的摩擦学性能,并利用扫描电子微镜（ＳＥＭ）对ＰＴＦＥ及纳米ＺｎＯ／ＰＴＦＥ复合材料的微观结构、磨损表面和转移膜进行了观察和分析。结果表明,纳米ＺｎＯ／ＰＴＦＥ复合材料的摩擦性能与纯ＰＴＦＥ基本相当,但耐磨性明显优于后者,纳米ＺｎＯ在复合材料中的最佳含量为１５ｖｏｌ．％左右。     

Effect of rare earths on mechanical and tribological properties of carbon fibers reinforced PTFE composite

The effect of a rare earth (RE) surface treatment on the mechanical and tribological properties of carbon fiber (CF) reinforced polytetrafluoroethylene (PTFE) composites was experimentally investigated. The tensile properties of the CF reinforced PTFE (CF/PTFE) composites treated with air oxidation and RE modifier were superior to those of untreated CF/PTFE composites, while RE treatment was most effective in promoting the tensile strength and strain at break of the CF/PTFE composite. The bending strength of the RE treated CF/PTFE composite was improved by about 16% compared with that of untreated composites, while 2% improvement was achieved by air oxidation. Under oil-lubricated conditions, RE treatment was more effective than air oxidation to reduce the friction coefficient and wear of PTFE composite. RE treatment effectively improved the interfacial adhesion between CF and PTFE. The strong interfacial coupling of the composite made CF not easy to detach from the PTFE matrix, and prevented the rubbing-off of PTFE, accordingly improved the friction and wear properties of the composite.     

SiC颗粒增强PTFE基复合材料磨损图的研究

研究了SiC颗粒增强PTFE基复合材料(PTFE／SiCp)在干摩擦条件下的磨损特性。对磨损表面进行了观察分析，建立了复合材料磨损机制转变图，对在不同磨损条件下的磨损机制进行了概括。结果表明，SiC颗粒增强PTFE基复合材料发生轻微磨损的主要机制是显微切削，发生严重磨损的主要机制是粘着磨损。     

Friction and wear characteristics of lead and its compounds filled polytetrafluoroethylene composites under oil lubricated conditions

The friction and wear properties of Pb, PbO, Pb₃O₄, or PbS filled polytetrafluoroethylene (PTFE) composites sliding against GCr15 bearing steel under both dry and liquid paraffin lubricated conditions were studied by using an MHK-500 ring-block wear tester. The worn surfaces and the transfer films of these PTFE composites formed on the surface of GCr15 bearing steel were then investigated by using a scanning electron microscope (SEM) and an optical microscope, respectively. Experimental results show that filling Pb, PbO, Pb₃O₄ or PbS to PTFE can greatly reduce the wear of the PTFE composites, but the wear reducing action of Pb₃O₄ is the most effective. Meanwhile, PbS increases the friction coefficient of the PTFE composite, but Pb and Pb₃O₄ reduce the friction coefficients of the PTFE composites. However, the friction and wear properties of lead or its compounds filled PTFE composites can be greatly improved by lubrication with liquid paraffin, and the friction coefficients of the PTFE composites can be decreased by one order of magnitude. Optical microscope investigation of transfer films shows that Pb, PbO, Pb₃O₄ and PbS enhance the adhesion of the transfer films to the surface of GCr15 bearing steel, so they greatly reduce the wear of the PTFE composites. However, the transfer of the PTFE composites onto the surface of GCr15 bearing steel can be greatly reduced by lubrication with liquid paraffin, but the transfer still takes place. SEM examination of worn surfaces shows that the interaction between liquid paraffin and the PTFE composites creates some cracks on the worn surfaces of the PTFE composites; the creation and development of the cracks reduces the load-carrying capacity of the PTFE composites, and this leads to deterioration of the friction and wear properties of the PTFE composites filled with lead or its compounds under higher loads in liquid paraffin lubrication.     

Preliminary studies of the influence of cryo‐treatment on the mechanical and tribological properties of ptfe and composites

Cryogenic treatment of polytetrafluoroethylene (PTFE) has proved beneficial in improving the abrasive wear resistance of several polymers, and it was thus assessed in an adhesive wear mode, as well. Preliminary investigations on the effect of cryogenic treatment on the tribological properties, in adhesive wear mode, and mechanical properties of neat PTFE and it composites filled with bronze or short glass fibres (GF) were carried out. It was found that, although the improvement in the wear and friction performance of neat PTFE and a GF + PTFE composite was significant, no such positive effect was observed for the bronze + PTFE composite. On the contrary, this composite showed a deterioration in performance. The reason behind the improvement in the tribological behaviour of neat PTFE and the GF + PTFE composite could not be clearly understood. However, it was confirmed that, if the treatment adversely affected the mechanical properties, then the tribological performance also deteriorated. An examination of the worn surface of the material and the counterface disc using a scanning electron microscope revealed changes in the microstructure due to the treatment. It was also confirmed from these SEM studies that the compatibility of bronze and PTFE was very poor, which led to poor performance of the composite both in the untreated and the cryo‐treated form. Further detailed investigation and analysis of various materials and composites, however, are necessary to establish the utility of this technique.     

水凝胶/热塑性聚氨酯复合材料在水润滑条件下的摩擦学性能

为提高水润滑轴承的承载能力，利用水凝胶在水润滑条件下的水合作用来改善热塑性聚氨酯（TPU）轴承材料的摩擦学性能。利用聚乙烯醇、海藻酸钠、壳聚糖等材料制备水凝胶颗粒，并通过熔融共混法制备水凝胶/TPU复合材料；在0.3和0.5 MPa的载荷下测试复合材料的摩擦磨损性能，利用激光干涉表面轮廓仪和扫描电子显微镜观察其磨损表面形貌，分析其磨损机制。结果表明：水凝胶微粒可以通过水合润滑改善摩擦副的润滑条件，从而降低摩擦因数和磨损量，提高复合材料的摩擦性能；水凝胶质量分数4%时复合材料具有最佳的摩擦磨损性能，其在0.3和0.5 MPa工况下相对于TPU试样的平均摩擦因数减少率分别为52.31%和43.94%。研究结果为开发高性能水润滑轴承材料提供了一种方法。