炭布高温预处理对C/C复合材料摩擦磨损性能的影响

采用炭布叠层为坯体,经等温ＣＶＤ工艺制备Ｃ／Ｃ复合材料,并对其摩擦磨损性能进行初步探讨,结果表明,炭布高温预处理能改善Ｃ／Ｃ复合材料的摩擦磨损性能,随着刹车压力的增大,试样的磨损率增大而摩擦系数则减小。     

“三明治”C/C复合材料及其摩擦磨损性能

通过化学气相渗透法(CVI)制备出一种新型的"三明治"结构的C/C复合材料。其两侧是纯网胎结构的功能层,主要承担摩擦功能;中间为承担结构作用的结构层,与传统针刺毡结构一致。系统研究了材料的微观组织结构特征及其摩擦磨损性能。结果表明:"三明治"C/C复合材料各个区域的热解炭都为粗糙层结构;刹车性能较传统三维针刺结构C/C复合材料的摩擦性能稳定;在摩擦试验过程中,摩擦面能够形成一层连续均匀的薄膜,使材料在刹车过程中具有较稳定的摩擦系数并能够有效降低材料的磨损率。     

热处理温度对C／C复合材料摩擦磨损性能的影响

利用销一盘式摩擦磨损试验机研究了不同热处理温度制备C／C复合材料与GCrl5钢配副在油润滑务件下的摩擦磨损行为。结果表明,在油润滑条件下,材料摩擦系数低,其值在0．06～0．17范围内,磨损率在（1．03～2．56）×10^4mg／N·m范围,其中2100℃热处理的材料具有最低的摩擦系数和磨损率。在摩擦试验过程中,2000℃以上热处理的材料可以形成完整致密的摩擦膜,能起到润滑作用。结果还表明,随热处理温度的提高,材料石墨化程度提高,硬度降低,其磨损机制以磨粒磨损为主转向以疲劳磨损和粘着磨损占据主导地位。     

刹车速度对C/C-SiC复合材料摩擦磨损性能的影响

对反应熔体渗透工艺制备的C/C-SiC复合材料,在MM-1000型摩擦磨损试验机上进行了模拟飞机制动刹车实验,重点研究了C/C-SiC复合材料在不同刹车速度下的摩擦磨损性能.研究表明:随着刹车速度的增加,C/C-SiC复合材料的摩擦系数先少许增加然后再减小,在10 m/s时达到最大值0.52.磨损率在低速时保持较低的数值,随着刹车速度的增加呈线性增加,但仍小于C/C复合材料的磨损率,表明C/C-SiC复合材料具有优良的耐磨损性能.当刹车速度超过20 m/s时,由于能载水平较高,摩擦表面出现犁沟现象并形成大量球状磨屑,摩擦系数急剧减小.     

PPS复合材料干摩擦磨损性能研究进展

介绍了聚苯硫醚（PPS）在摩擦材料领域发展的优势。按照耐磨材料的常用添加剂类别对PPS摩擦磨损影响进行了详细的综述，并根据扫描电子显微镜（SEM）和X射线光电子能谱（XPS）等分析对其机理进一步解释。总结了不同测试条件对摩擦性能的影响进行，并提出进一步研究方向。     

碳纳米管改性镀铜石墨/铜复合材料摩擦磨损性能的研究

采用放电等离子烧结(SPS)工艺制备碳纳米管(CNTs)含量为0～0.3 wt%的碳纳米管-镀铜石墨/铜(CNTs-CCG/Cu)复合材料,研究了CNTs含量对复合材料物理、力学和摩擦磨损性能的影响。实验结果表明：随着CNTs含量从0增加至0.3 wt%,复合材料电阻增加,抗弯强度先升高后降低,在其添加量为0.1 wt%时达到最大值124.5 MPa。摩擦系数和磨损率先降低后升高,在CNTs添加量为0.1 wt%时最低,分别为0.15左右和9.63×10^-14 m³N^-1m^-1。摩擦过程中适量的CNTs协同CCG在材料表面形成高强度连续摩擦膜,有效降低了复合材料的摩擦系数和磨损率。     

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。     

PA66/PTFE复合材料的摩擦磨损性能

采用机械共混的方法制备了PA66/PTFE复合材料,研究了聚四氟乙烯(PTFE)改性尼龙66( PA66)复合材料的摩擦磨损性能,并采用扫描电镜( SEM)观察了材料的磨损表面.结果表明:PTFE的加入可以有效改善尼龙66的摩擦性能,当PTFE质量分数为9％时,摩擦系数为纯PA66的57％左右,磨损量为纯PA66的43％左右,综合耐磨性最好.磨损面的扫描电镜观察发现,材料的磨损以黏着磨损和磨粒磨损为主,PTFE在共混体系中形成了微纤结构.     

炭/炭复合材料的摩擦磨损性能及应用

论述了炭／炭复合材料的特点，结合该材料在飞机刹车盘中的具体应用，讨论了炭／炭复合材料在不同环境气氛下的摩擦磨损行为及其影响因素，并阐明了炭／炭复合材料的研究现状和尚需解决的问题。     

碳纳米管改性PTFE复合材料摩擦磨损性能

以强酸氧化后不同含量的碳纳米管(CNTs)为填料制备了聚四氟乙烯(PTFE)/CNTs复合材料,研究其摩擦磨损情况。结果表明:CNTs填充质量分数为0,1%,3%,5%,7%时,PTFE/CNTs复合材料的摩擦系数随转速的增大而增大;20,40,60,80 r/min转速下,复合材料摩擦系数随碳纳米管填充质量分数的增加先增大后减小,当填充量为5%时,各转速下的摩擦系数均达到最大值。三维视频显微镜观察样品的表面磨痕深度并计算试样平均体积磨损率,发现填充CNTs可显著降低复合材料体积磨损率,当填充量大于5%后,复合材料体积磨损率增大。扫描电子显微镜观察发现:CNTs质量分数小于5%时,CNTs有效抑制PTFE的犁削,这种抑制作用随CNTs质量分数增大而增大,当质量分数为7%时,PTFE/CNTs复合材料犁削加剧,其原因为CNTs发生团聚,对PTFE分子链的约束作用弱化,使得分子链被拉出结晶区域。     

Friction and wear properties of NBR/PVC composites

Acrylonitrial butadiene rubber (NBR)/Polyvinyl chloride (PVC) composites with different PVC content were prepared. The effect of PVC content on the mechanical strength and tribological properties of the NBR/PVC composites was investigated. The morphologies of the worn traces and debris of NBR/PVC composites and worn traces of mating ball were observed using a scanning electron microscope (SEM). It was found that the friction and wear of NBR/PVC was lower than that of NBR without PVC. The NBR/PVC composite with 30% PVC content showed the best synthetic mechanical and tribological properties. The inferior elastic properties and the lesser deformation under the applied load of composites with PVC resulted in hysteric force and adhesion force decrease, which leading to a lower friction and wear of NBR/PVC composites. The frictional failure unit of NBR70/PVC30 composite being smaller should be an important reason of the wear of the composite being lowest. The lubricating effect of PVC played an important role in decreasing the friction coefficient and wear of NBR/PVC composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

不同介质中聚四氟乙烯复合材料的摩擦磨损性能

分别在碱液、水、油和干摩擦条件下考察了碳纤维和玻璃纤维填充聚四氟乙烯复合材料的摩擦磨损性能。利用SEM观察了不同介质中磨损面和对摩面的形貌,并探讨了其磨损机理。结果表明,不同介质中摩擦系数的大小关系是μ干>μ水或油>μ碱,磨损率是W水>W干>W碱或油。水、碱和油都不同程度地阻止了转移膜的形成。碱液和油具有很好的冷却与润滑作用,摩擦系数低,磨损小;然而水分子降低了填料和基体的界面粘接强度,造成犁削和磨粒磨损加重。     

Friction and wear properties of basalt fiber reinforced/solid lubricants filled polyimide composites under different sliding conditions

Short basalt fibers (BFs)‐reinforced polyimide (PI) composites filled with MoS₂ and graphite were fabricated by means of hot‐press molding technique. The tribological properties of the resulting composites sliding against GCr15 steel ring were investigated on a model ring‐on‐block test rig. The wear mechanisms were also comparatively discussed, based on scanning electron microscopic examination of the worn surface of the PI composites and the transfer film formed on the counterpart. Experimental results revealed that MoS₂ and graphite as fillers significantly improved the wear resistance of the BFs‐reinforced polyimide (BFs/PI) composites. For the best combination of friction coefficient and wear rate, the optimal volume content of MoS₂ and graphite in the composites appears to be 40 and 35%, respectively. It was also found that the tribological properties of the filled BFs/PI composites were closely related with the sliding conditions such as sliding speed and applied load. Research results show that the BF/PI composites exhibited better tribological properties under higher PV product. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Friction and wear behavior of alumina-based graphene and CNFs composites

Alumina – carbon nanofibers (CNF) and alumina – graphene oxide (GO) composites were prepared by spark plasma sintering using freeze-dried powders prepared from optimized suspensions of the mixtures. The tribological behavior was studied using the ball-on-disk technique in dry sliding at ambient conditions and compared to a monolithic alumina used as a reference. At low loads there was little difference between friction and wear behavior, whereas at moderate loads the composites showed a noticeable reduction in wear rate over monolithic alumina, five and 2.5 times for the GO and the CNF composite respectively; the friction coefficient slightly decreased for the alumina – GO material. This behavior is related to the presence of a carbon-rich protecting tribofilm. The film present in the alumina – GO showed better tribological performance due to the absence of coalescence of cracks that led to delamination events in the case of the alumina – CNF composite.     

Friction and wear behaviour of silicon carbide/graphene composites under isooctane lubrication

The tribological performance of silicon carbide (SiC)/graphene nanoplatelets (GNPs) composites is analysed under oscillating sliding tests lubricated with isooctane, looking to explore their potential as components for gasoline direct injection (GDI) engines. High graphene filler contents (20?vol.% of GNPs) are required to substantially reduce the friction coefficient of SiC ceramics, attaining decreases on friction up to 30% independently of the applied load. For all materials and testing conditions a mild wear regime is evidenced. SiC/20?vol.% GNPs composite also enhances the wear resistance up to 35% at low load, but the addition of GNPs produces a deleterious effect as the load augments. The tribological behaviour depends on the formation and destabilization of a solid lubricant carbon-based tribofilm and strongly correlates with the mechanical properties of the tested materials.     

Electrical properties of C/C and C/C-SiC ceramic fibre composites

The electrical properties of carbon/carbon (C/C) and carbon/carbon-silicon carbide (C/C-SiC) ceramic composites were measured. The results show that the capacitance decreases rapidly with an increase in frequency and it becomes constant above a frequency of 500 kHz, whereas the dissipation factor increases with increasing frequency. C/C-SiC composites give higher value than C/C composites due to the presence of microcracks.     

表面处理对CF/PA66复合材料磨损性能的影响

采用电化学氧化法和氨气法分别对碳纤维(CF)进行表面处理后,用双螺杆挤出机共混造粒和注塑成型制备CF/PA66复合材料,研究了表面处理对CF/PA66复合材料磨损性能的影向。结果表明:随着CF含量的增加,CF/PA66复合材料的耐磨损性能提高;对CF进行表面处理,可提高CF/PA66复合材料的耐磨损性能,氨气法得到的CF/PA66复合材料的耐磨损性能优于电化学氧化法,当添加CF质量分数为15%时,其体积磨损速率比电化学氧化法的约降低48%。     

针刺C/C复合材料拉伸性能和韧性的研究进展

综述了近年来国内外针刺C／C复合材料拉伸性能和韧性研究进展,归纳了影响针刺C／C复合材料拉伸性能和韧性的主要因素,即炭纤维、炭基体、界面和针刺工艺参数等,初步得到了提高材料拉伸性能和韧性的方法：提高针刺C／C材料拉伸性能的方法主要是提高纤维体积分数;提高针刺C／C材料韧性的方法主要是改善致密工艺。在此基础上,对未来的进一步研究进行展望。     

Friction and wear characteristics of ceramic particle filled polytetrafluoroethylene composites under oil-lubricated conditions

Five kinds of polytetrafluoroethylene (PTFE)-based composites were prepared: PTFE, PTFE + 30 vol % SiC, PTFE + 30 vol % Si₃N₄, PTFE + 30 vol % BN, and PTFE + 30 vol % B₂O₃. The friction and wear properties of these ceramic particle filled 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 formed on the surface of the GCr15 bearing steel of these PTFE composites were investigated by using a scanning electron microscope (SEM)and an optical microscope, respectively. The experimental results show that the ceramic particles of SiC, Si₃N₄, BN, and B₂O₃ can greatly reduce the wear of the PTFE composites; the wear-reducing action of Si₃N₄ is the most effective, that of SiC is the next most effective, then the BN, and that of B₂O₃ is the worst. We found that B₂O₃ reduces the friction coefficient of the PTFE composite but SiC, Si₃N₄, and BN increase the friction coefficients of the PTFE composites. However, the friction and wear properties of the ceramic particle filled PTFE composites can be greatly improved by lubrication with liquid paraffin, and the friction coefficients of the PTFE composites can be decreased by 1 order of magnitude. Under lubrication of liquid paraffin the friction coefficients of these ceramic particle filled PTFE composites decrease with an increase of load, but the wear of the PTFE composites increases with a load increase. The variations of the friction coefficients with load for these ceramic particle filled PTFE composites under lubrication of liquid paraffin can be properly described by the relationship between the friction coefficient (μ) and the simplified Sommerfeld variable N/P as given here. The investigations of the frictional surfaces show that the ceramic particles SiC, Si₃N₄, BN, and B₂O₃ enhance the adhesion of the transfer films of the PTFE composites 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 the GCr15 bearing steel can be greatly reduced by lubrication with liquid paraffin, but the transfer still takes place. Meanwhile, the interactions between the liquid paraffin and the PTFE composites, especially the absorption of liquid paraffin into the surface layers of the PTFE composites, create some cracks on the worn surfaces of the ceramic particle filled PTFE composites; the creation and development of these cracks reduces the load-supporting capacity of the PTFE composites. This leads to the deterioration of the friction and wear properties of the PTFE composites under higher loads in liquid paraffin lubrication. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2611–2619, 1999