碳纤维乒乓球底板的制备与摩擦性能研究

对新球时代碳纤维兵乓球底板进行了不同载荷和温度的摩擦磨损试验,研究了载荷和温度对摩擦系数、磨损量和磨损形貌的影响。结果表明,在较低的载荷(100N)下,碳纤维复合材料的磨损量约为2.03mg;当载荷增加至150N和200N时,碳纤维复合材料的磨损量分别提高至3.37mg和3.52mg。载荷100N时碳纤维复合材料的磨损机制主要为磨粒磨损,载荷增加至150N和200N时,碳纤维复合材料的磨损机制主要为疲劳磨损。随着温度从25℃减小至-25℃,100N和200N载荷下的碳纤维复合材料的磨损量都呈现逐渐升高的趋势,温度的降低会增加载荷为100N和200N时碳纤维复合材料的磨损量。     

不同填料对PTFE复合材料力学性能和摩擦学性能的影响

为探索不同填料及其含量对往复压缩机密封件用聚四氟乙烯(PTFE)复合材料力学性能和摩擦学性能的影响,采用微机控制电子万能试验机和立式万能摩擦磨损试验机检测不同玻璃纤维、石墨和碳纤维含量的PTFE复合材料力学性能和磨损性能。并采用扫描电子显微镜(SEM)对摩擦磨损试样表面的微观形貌进行分析。结果表明:添加石墨以及一定含量以上的玻纤和碳纤,会降低PTFE复合材料的拉伸强度和断裂伸长率。复合材料的磨损量随着玻纤含量的增加而提高,石墨和一定含量内的碳纤使复合材料的磨损量下降。在摩擦过程中,磨粒磨损与黏着磨损并存,不添加碳纤,只含石墨和玻纤的复合材料以磨粒磨损为主,而添加碳纤维,同时含玻璃纤维和石墨的复合材料以黏着磨损为主。随着玻纤和碳纤的增加,复合材料的硬度逐渐增加,而石墨的加入会降低复合材料的硬度。     

纤维增强铝硅酸盐玻璃陶瓷复合材料的摩擦学特性研究

在UMT-2微观磨损试验机（USA）上研究了SiC纤维增强铝硅酸盐玻璃陶瓷复合材料的摩擦学特性,且对摩擦表面进行了SEM观察和分析。研究结果表明：随着SiC纤维含量的增加,摩擦系数逐渐降低,但变化幅度较小。而当纤维含量（体积）低于25％时,复合材料的磨损量明显降低,而显微硬度却有较大提高;超过25％时,继续增加纤维的含量会导致复合材料耐磨性下降。SiC纤维增强铝硅酸盐玻璃陶瓷复合材料的摩擦系数随着载荷的增大显现先增大后减小的趋势,并且在载荷140N时达到最大值,而磨损量随着载荷的增大而增加。复合材料的主要磨损失效形式为磨粒磨损。     

球形燃料元件基体石墨摩擦磨损性能的研究

利用OHT-1000E型摩擦磨损试验机系统研究了氦气中高温气冷堆球形燃料元件基体石墨在不同温度及载荷下的摩擦磨损性能,并与其摩擦磨损后的微观形貌相结合,对其摩擦磨损的机理进行分析。结果表明:在氦气中,不同温度下基体石墨的摩擦磨损性能差异很大,而且在不同载荷下,温度对基体石墨的摩擦磨损性能影响不同。在低载荷下,基体石墨在400~700℃温度范围的摩擦系数较大,在其他温度范围的摩擦系数都相对较小;在高载荷下,基体石墨在100~200℃和400~700℃温度范围的摩擦系数较大,在其他温度范围的摩擦系数都相对较小,载荷主要影响较低温度(100~200℃)下的摩擦磨损性能。基体石墨的摩擦系数、磨损量及其磨损机理有较好的对应关系:当基体石墨的摩擦系数大时,对应的磨损量较多,磨损机理主要为粘着磨损;当基体石墨的摩擦系数较小时,对应的磨损量也较小,磨损机理主要为磨粒磨损。     

PTFE/BaSO4复合材料摩擦磨损性能研究

用M-2000型摩擦磨损试验机研究了干摩擦条件下BaSO4用量，载荷，对磨时间对聚四氟乙烯（PTFE）复合材料摩擦磨损性能的影响。在本实验条件下，PTFE/BaSO4复合材料的摩擦系灵敏随着BaSO4含量的增加而增大，抗磨损能力则有一个最佳含量；随着载荷的增加，材料的摩擦系数，磨损量和磨痕宽度也随之增大，磨损量随着对磨时间的延长而波动变小并趋于稳定。     

弹性金属塑料复合材料摩擦系数的方程拟合及其应用

基于弹性金属塑料复合材料,对其摩擦系数的方程拟合及其应用进行了研究。结果表明,摩擦系数随摩擦时间的延长逐步趋于稳定,此时开始进入摩擦磨损的稳定阶段。如果将石墨添加到塑料工作层当中,将会构建层状结构,并与PPS、TPI、TLCP热塑性材料发生协同效应,从而促进金属表面均匀致密的自润滑转移膜的形成。增大复合材料的载荷和转速,此时能够确保以更短的时间进入到摩擦稳定阶段,也就是说增加转速和载荷以后,可以实现形成转移膜时间的前移。磨损体积和摩擦系数随塑料工作层材料配比的不同具有显著的变化,磨损量也有所不同。随着石墨和热塑性聚酰亚胺(TPI)的增加,在载荷增加时,复合材料摩擦系数变化量比其他配比要小。采用软件MATLAB7.0,根据复合材料的摩擦系数、结合强度和塑料工作层对数据进行拟合,从而获得塑料工作层配比和摩擦系数、结合强度间的拟合函数。     

PTFE/纳米SiC复合材料的摩擦磨损性能研究

利用冷压烧结法制备了不同含量的聚四氟乙烯/纳米碳化硅(PTFE/纳米SiC)复合材料。采用MM-200型摩擦磨损试验机在干摩擦条件下考察了纳米SiC含量及载荷对PTFE/纳米SiC复合材料摩擦磨损性能的影响,借助于扫描电子显微镜观察分析了试样磨损表面形貌,并探讨了其磨损机理。结果表明,纳米SiC能够提高PTFE/纳米SiC复合材料的硬度和耐磨性,当纳米SiC质量分数为7%时,PTFE/纳米SiC复合材料的磨损量最小,摩擦系数也最小;随纳米SiC含量的增加,其摩擦系数有所增大;随着载荷的增大,PTFE/纳米SiC复合材料的磨损量增加。     

反应热压制备C/W2B5复合材料的力学和摩擦磨损性能

采用热压方法,利用碳化硼和碳化钨之间的固相化学反应,原位生成C/W2B5复合材料.这种复合材料具有较高的致密度,优异的力学性能和摩擦磨损性能.高陶瓷含量复合材料抗弯强度和断裂韧性分别高达768.2MPa和8.89MPa*m1/2;而高碳含量复合材料的摩擦系数与石墨的摩擦系数相当,而磨损量却低于石墨的磨损量.     

玻璃纤维增强PEEK复合材料的高速干摩擦性能

利用球盘式摩擦磨损试验机对质量分数为30%的短切玻璃纤维增强聚醚醚酮(PEEK/GF)复合材料进行室温高速条件下干滑动磨损实验,考察了载荷及频率对材料摩擦系数及磨损量的影响,并对摩擦前后的微观形貌及热性能进行了分析。结果表明,随着载荷和频率的增加,PEEK/GF复合材料的摩擦系数和磨损量逐渐增大并趋于稳定;微观结构分析显示GF与PEEK两相结合紧密,磨损方式主要以犁沟为主,GF的加入阻断了PEEK从PEEK/GF复合材料磨损表面剥落,使PEEK磨屑在GF周围积聚,摩擦表面产生的热量使PEEK收缩团聚在一起;PEEK/GF复合材料的热分解温度比纯PEEK提高了75℃。     

酚醛树脂基复合材料摩擦性能研究

采用MPX-2000型销盘式摩擦磨损试验机评价了分别填充氧化铝、Cu粉、石墨、石墨与Cu粉复配的酚醛树脂基复合材料在载荷为100 N、转速为500 r∕min、室温干摩擦条件下的滑动摩擦磨损性能,并分析了磨损后的表面形貌。结果表明,与未填充相比,填充试样的平均摩擦系数和磨损量均有不同程度的降低,其中由石墨、石墨与Cu粉复配填充试样的磨损量显著降低,分别下降80.7%,84.8%。未填充试样磨损表面出现少量被拔出的磨屑纤维,未见明显润滑膜;而填充试样的磨损表面呈现出明显、均匀的润滑膜。填料改变了酚醛树脂基复合材料的磨损机理,增强了复合材料的抗极压承载和促进润滑膜形成能力,提高了复合材料的摩擦磨损性能。     

Influence of solid lubricant reinforcement on wear behavior of Kevlar fabric composites

The friction and wear behavior of Kevlar fabric composites reinforced by PTFE or graphite powders was investigated using a Xuanwu‐III friction and wear tester at dry sliding condition, with the unfilled Kevlar fabric composite as a reference. The worn surfaces were analyzed by means of scanning electron microscope, and X‐ray photoelectron spectroscopy. It was found that PTFE or graphite as fillers could significantly improve the tribological behavior of the Kevlar fabric composites, and the Kevlar fabric composites filled with 20% PTFE exhibited the best antiwear and antifriction ability among all evaluated cases. The transfer films established with two lubricants in sliding wear of composites against metallic counterparts made contributions to reducing friction coefficient and wear rate of Kevlar fabric composites. In particular, FeF₂ generated in the sliding of Kevlar fabric composites filled with PTFE against counterpart pin improved the bonding strength between the transfer film and counterpart surface, which accounted for the lowest friction coefficient and wear rate of the Kevlar fabric composites filled with PTFE measured in the testing. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.     

Role of internal additives in the friction and wear of carbon‐fiber‐reinforced polyimide

Polyimide composites should function in sliding contacts under high temperatures, but the interference of carbon fibers with sliding mechanisms is difficult to predict: they often increase the coefficients of friction and act abrasively but show lubricating properties under other conditions. The friction and wear behavior of thermoplastic polyimides reinforced with short carbon fibers and filled with solid internal lubricant (polytetrafluoroethylene) or silicon oil was investigated in this study with a reciprocating cylinder‐on‐plate tester under 50 N at 0.3 m/s with steel counterfaces that were heated at 23–260°C. We concluded that polytetrafluoroethylene additives effectively reduced the coefficients of friction over the entire temperature range, especially under thermally controlled sliding conditions at 120°C, whereas the internal silicon oil increased the coefficients of friction. The wear rates of the fiber‐reinforced polyimide significantly decreased with respect to those of the thermoplastic polyimide, whereas additional fillers slightly increased the wear rates. We further analyzed the role of internal additives by considering the deformation and maximum polymer surface temperature during sliding. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effects of the combination of solid lubricants and short carbon fibers on the sliding performance of poly(ether imide) matrix composites

Solid lubricants, that is, graphite flakes and poly(tetrafluoroethylene) powders, were incorporated with short carbon fibers into a poly(ether imide) matrix to improve the tribological performance. Wear tests were performed with a polymer pin against a mild steel counterpart at a constant sliding speed of 1 m/s under various temperatures and contact pressures. Composites filled with equilibrium contents of solid lubricants and short carbon fibers, that is, 10 vol % of each filler, exhibited the lowest wear rate and friction coefficient. The relatively lower concentration of solid lubricants adversely affected the wear resistance, whereas the friction coefficient did not vary significantly in comparison with the friction coefficient of the composites filled with only short carbon fibers. The improved tribological behavior was attributed to more continuous and effective friction films formed on the material pairs during sliding. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1428–1434, 2004     

玻璃纤维及石墨增强聚四氟乙烯复合材料摩擦磨损性能的研究

用机械混合、冷压成型和烧结的方法制备了不同质量分数(5%~30%)的玻纤和石墨填充聚四氟乙烯(PTFE)复合材料制品。用M-2000型磨损试验机评价了不同样品在干摩擦下的磨损性能,揭示了填料玻纤和石墨对PTFE复合材料磨损性能的影响,并对磨损机理进行了探讨。用扫描电镜(SEM)对试样磨损形貌进行观察。结果表明:对玻纤进行改性能极大地提高PTFE复合材料的耐磨性能,同时可提高复合材料硬度;玻纤和石墨协同作用,对改善PTFE摩擦磨损性能有比较显著的效果;20%玻纤 10%石墨填充PTFE复合材料有着较好的摩擦磨损性能。     

混杂填料增强聚四氟乙烯复合材料的摩擦学性能研究

采用MM-200型摩擦磨损试验机对纳米SiC、MoS2和石墨填充聚四氟乙烯(PTFE)复合材料在干摩擦条件下与45#钢对摩时的摩擦磨损性能进行了研究,探讨了MoS2、石墨及纳米SiC的协同效应。认为纳米SiC的加入大大提高了复合材料的承载能力,石墨、MoS2的加入减少PTFE复合材料的摩擦因数。利用扫描电子显微镜(SEM)对PTFE复合材料的摩擦面进行了观察。结果表明:实验中5%nano-SiC和3%MoS2填充PTFE复合材料的摩擦磨损性能最好,且在高载荷下的摩擦磨损性能尤为突出,具有一定的应用价值。     

Friction and wear bahavior of short fiber-reinforced poly(amide-imide) composites

Tribological behavior of short fiber-reinforced thermoplastic composites was investigated experimentally and theoretically. Short carbon fiber and glass fiber reinforced poly(amide-imide) composites were tested. Titanium oxide powder-filled composite was also tested for comparison with the fiber composites. Block-on-ring type wear testing was performed for 24 h at three different sliding conditions. Frictional force was measured and stored by a data acquisition system and wear was measured as weight loss after the test. Wear tracks on the specimen and the counterface were examined with an optical microscope to observe fiber damage and formation of wear film. The equivalent stress distribution around each fiber at the sliding surface was calculated by employing a finite element program. The lowest friction and wear was obtained for the carbon fiber composite, the highest friction for the glass fiber composite, and the highest wear for TiO₂-filled one. It was observed that the glass fibers are damaged and removed from the surface more easily than the carbon fibers, and the finite element analysis also suggests easier debonding of glass fibers.     

Elastomer modified phenolic resin-based composites with reduced scale friction: Influence of calcined petroleum coke on tribological and thermo-mechanical behavior

The present investigation deals with the effect of the concentration of calcined petroleum coke (CPC) on the dry sliding wear characteristics of elastomer modified phenolic resin-based friction composites. Other ingredients common in brake formulations like fiber, filler, and solid lubricant were excluded in the present formulations to understand the exclusive effect of the CPC concentration on the frictional, mechanical, and thermal properties of these composites. The composites were fabricated by hot mixing followed by compression molding, and subsequent post-curing. The coefficient of friction (COF) and the specific wear rate of these composites sliding against a cast-iron disc were measured and analyzed. The change in surface topography of these composites before and after sliding operation was investigated by scanning electron microscopy. An effort was made to correlate the surface morphology of these composites before and after sliding with friction and wear behavior. The investigation reveals that CPC inclusion improved the anti-wear behavior as it formed a uniform transfer layer over the rubbing surfaces. In case of optimum CPC loaded (200 phr) composite, the average COF and thermal conductivity values were found to be 0.15 and 0.61 W/m-K, respectively, as compared to 0.12 and 0.25 W/m-K for the base composite (without any CPC).     

Mechanical and tribological properties of glass–epoxy composites with and without graphite particulate filler

The objectives of this research article is to evaluate the mechanical and tribological properties of glass‐fiber‐reinforced epoxy (G–E) composites with and without graphite particulate filler. The laminates were fabricated by a dry hand layup technique. The mechanical properties, including tensile strength, tensile modulus, elongation at break, and surface hardness, were investigated in accordance with ASTM standards. From the experimental investigation, we found that the tensile strength and dimensional stability of the G–E composite increased with increasing graphite content. The effect of filler content (0–7.5 wt %) and sliding distance on the friction and wear behavior of the graphite‐filled G–E composite systems were studied. Also, conventional weighing, determination of the coefficient of friction, and examination of the worn surface morphological features by scanning electron microscopy (SEM) were done. A marginal increase in the coefficient of friction with sliding distance for the unfilled composites was noticed, but a slight reduction was noticed for the graphite‐filled composites. The 7.5% graphite‐filled G–E composite showed a lower friction coefficient for the sliding distances used. The wear loss of the composites decreased with increasing weight fraction of graphite filler and increased with increasing sliding distance. Failure mechanisms of the worn surfaces of the filled composites were established with SEM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2472–2480, 2007     

Tribological behavior of polyetheretherketone composites containing short carbon fibers and potassium titanate whiskers in dry sliding against steel

Polyetheretherketone (PEEK) composites reinforced by short carbon fibers (SCF) and potassium titanate whiskers (PTW) were prepared using twin‐screw extrusion compounding and injection molding. The tribological properties of hybrid composites were investigated in dry sliding condition against steel. The effects of filler contents on the wear behavior were studied. It was found that the hybrid composite showed an excellent tribological property in dry sliding condition. Applied load had great effect on the tribological behavior of the composites. In most cases, the friction coefficient of the composite decreased with the load rising. The composites with higher CF contents showed outstanding tribological performances at low load but could worsen the wear behavior at high load. Because of the positive effect of PTW, high PTW loading composites presented low wear rate at low load. At high loads, the composites with lower PTW contents had better wear resistance. The scanning electron microscopy (SEM) observation revealed that abrasion wear was attributed to the lower wear resistance of the high PTW content composite at high load. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Friction and wear behavior of graphite fiber-reinforced composites

Friction and wear behavior of continuous graphite fiber composites was studied for different fiber orientations against the sliding direction. The effect of fiber orientation on friction and wear of the composite and on deformation of the counterface was investigated experimentally. A pin on disk type testing machine was built and employed to generate friction and wear data. A graphite fiber composite plate was produced by the bleeder ply molding in an autoclave and machined into rectangular pin specimens with specific fiber orientations, i.e., normal, transverse, and longitudinal directions. Three different wear conditions were employed for two different periods of time, 24 and 48 hours. The wear track of the worn specimens and the metal counterface was examined and a scanning electron microscope (SEM) to observe the damaged fibers on the sliding surface of the specimen and wear film generation on the counterface. A wear mechanism of the continuous graphite fiber composite during sliding wear is proposed based on the experimental results.