碳纤维和二硫化钼混杂增强尼龙复合材料的摩擦学性能研究

以注塑成型法制备MoS₂和碳纤维混杂增强尼龙1010复合材料,采用MM-200型磨损试验机考察复合材料摩擦磨损性能。研究结果表明:在干摩擦条件下,MoS₂和碳纤维混杂可显著改善尼龙复合材料摩擦学性能,较小载荷下复合材料磨损以轻微磨粒磨损和疲劳磨损为主,较高载荷下复合材料则以热疲劳断裂剥落磨损为主。摩擦过程中MoS₂和对偶铁发生摩擦化学反应,生成和对偶底材具有较强结合能力的硫化亚铁和硫酸铁等,同时部分被氧化生成MoO₃。     

空心微珠-碳纤维共混改性聚酰亚胺复合材料的摩擦学性能

通过模压成型制备了碳纤维与空心微珠共混改性的聚酰亚胺复合材料,采用MRH-3型摩擦磨损试验机研究了空心微珠含量、滑动速度及载荷对复合材料摩擦学性能的影响,并对其磨损形貌及机制进行了分析.结果表明:空心微珠-碳纤维/聚酰亚胺复合材料摩擦学性能优于其单独填充的聚酰亚胺基复合材料;空心微珠含量对共混改性的复合材料摩擦系数影响不大,但其磨损率随着空心微珠含量的增加先减小后增大;15％空心微珠-10％碳纤维(质量分数)共混增强的复合材料的减摩耐磨性能最佳;随着滑动速度提高,空心微珠-碳纤维/聚酰亚胺复合材料的摩擦系数下降,磨损率增大;空心微珠-碳纤维/聚酰亚胺复合材料摩擦系数随着载荷增加先下降后上升,而磨损率则随着载荷增加而增大;空心微珠-碳纤维/聚酰亚胺的主要磨损机制在较低载荷时为磨粒磨损,在较高载荷时为粘着磨损和磨粒磨损.     

空心微珠-碳纤维共混改性聚酰亚胺复合材料的摩擦学性能

通过模压成型制备了碳纤维与空心微珠共混改性的聚酰亚胺复合材料, 采用MRH-3型摩擦磨损试验机研究了空心微珠含量、滑动速度及载荷对复合材料摩擦学性能的影响, 并对其磨损形貌及机制进行了分析。结果表明: 空心微珠-碳纤维/聚酰亚胺复合材料摩擦学性能优于其单独填充的聚酰亚胺基复合材料; 空心微珠含量对共混改性的复合材料摩擦系数影响不大, 但其磨损率随着空心微珠含量的增加先减小后增大; 15%空心微珠-10%碳纤维(质量分数)共混增强的复合材料的减摩耐磨性能最佳; 随着滑动速度提高, 空心微珠-碳纤维/聚酰亚胺复合材料的摩擦系数下降, 磨损率增大; 空心微珠-碳纤维/聚酰亚胺复合材料摩擦系数随着载荷增加先下降后上升, 而磨损率则随着载荷增加而增大; 空心微珠-碳纤维/聚酰亚胺的主要磨损机制在较低载荷时为磨粒磨损, 在较高载荷时为粘着磨损和磨粒磨损。     

聚醚醚酮及其复合材料的摩擦学研究进展

评述了聚醚醚酮（PEEK）及其复合材料的摩擦磨损性能，在滑动过程中形成的摩擦转移膜以及磨屑的研究，总结了聚合物基复合材料摩擦学研究的一般方法及规律，介绍了关于用PEEK复合材料制造的轴承，齿轮等进行的摩擦学研究，以及等离子体表面处理和颗粒增强对PEEK及其复合材料摩擦学性能的影响。     

粉末冶金法制备CNT和SiC混杂增强铝基复合材料的摩擦磨损性能EI北大核心CSCD

以7055Al为基体,通过粉末冶金法分别制备碳化硅(SiC)颗粒、碳纳米管(CNT)以及SiC和CNT混杂增强7055Al复合材料,并对三种复合材料的干滑动摩擦磨损行为进行研究。结果表明:随着载荷提高,复合材料磨损失重增加,摩擦因数略有降低。在0.5 MPa与1.0 MPa载荷条件下,SiC-CNT/7055Al复合材料磨损失重低于单一SiC/7055Al和单一CNT/7055Al复合材料。2.0 MPa时,SiC-CNT/7055Al复合材料磨损失重急剧增加。随着载荷提高,CNT/7055Al复合材料耐磨性逐渐增加,在中、高载荷下,材料具有更为优异的耐磨性。SiC/7055Al复合材料磨损量则随着载荷提高,磨损失重逐渐增加,当载荷为2.0 MPa时,材料磨损量增加幅度较小。     

酸性介质中不同聚醚醚酮纳微复合材料的耐蚀与耐磨性能

分别研究了不同质量分数的纳米SiC填充碳纤维/聚醚醚酮(CF/PEEK)和钛酸钾晶须/聚醚醚酮(PTW/PEEK)复合材料在pH=1的硫酸溶液中的耐蚀性能和摩擦学性能。采用电化学工作站评价复合材料的耐蚀性能,使用差热分析仪与扫描电镜分析了复合材料的玻璃化转变温度与磨损面的形貌,并讨论了复合材料的防腐和耐磨机理。结果表明,在腐蚀性介质中质量分数2.5%纳米SiC增强复合材料的耐蚀性最佳,此时纳米SiC增强PTW/PEEK复合材料的耐蚀性能优于纳米SiC增强CF/PEEK复合材料。在酸性环境下,2.5%纳米SiC增强复合材料的摩擦学性能最佳,在滑动摩擦过程中,PTW不但起到了承载的作用,而且暴露的PTW可以填充到对偶面的划痕之中,减小了纤维对复合材料的刮擦以及磨粒磨损程度,所以相同含量纳米SiC增强PTW/PEEK复合材料优于CF/PEEK的摩擦学性能,其耐磨性是CF/PEEK复合材料的5倍。     

玻璃纤维增强聚醚醚酮复合材料在水润滑下的摩擦学性能

利用球盘式摩擦磨损试验机考察了玻璃纤维(GF)增强聚醚醚酮(PEEK)复合材料在干摩擦和水润滑条件下的摩擦磨损性能,并探讨了其磨损机理。结果表明:在干摩擦和水润滑条件下,PEEK和GF/PEEK的摩擦因数和磨损率均随载荷和对磨时间的增加逐渐增大并趋于稳定,GF的加入可以显著降低GF/PEEK复合材料的摩擦因数和磨损率;在水润滑条件下,PEEK和GF/PEEK的摩擦因数和磨损率比干摩擦下显著降低。干摩擦下,PEEK以黏着磨损和磨粒磨损的混合磨损形式为主,水润滑条件下,磨损方式主要是以轻微的黏着磨损为主;干摩擦下,GF/PEEK磨损表面有大量的微观断裂裂纹和破碎,以磨粒磨损和疲劳磨损为主,水润滑条件下,磨损表面仅有微观切削的痕迹,磨损方式以轻微磨粒磨损为主。由于水的冷却和润滑作用,使得复合材料向对偶钢球的黏着转移明显减弱,同时阻止了对偶钢球上的Fe向复合材料磨损表面转移,从而减轻摩擦、降低摩擦表面温升,显著改善复合材料的摩擦磨损性能。     

纳米ZrO_2和聚醚醚酮填充聚四氟乙烯的摩擦学性能基于环-块摩擦模型的演变过程

用不同体积分数的纳米ZrO_2和聚醚醚酮(PEEK)颗粒填充改性聚四氟乙烯(PTFE)复合材料。使用环-块摩擦磨损试验机测试PTFE复合材料在滑动速度为2 m/s、载荷为200 N的试验条件下的摩擦学性能。获取不同阶段摩擦学性能的数据,计算出在整个试验过程中样品的瞬时磨损率。利用扫描电镜观察不同试验阶段对偶钢环表面形貌的变化图像并进行分析。利用仿真模拟软件(ABAQUS)对摩擦过程中PTFE复合材料的接触应力变化进行分析。结果表明,纳米ZrO_2和PEEK颗粒可以协同改善PTFE复合材料的摩擦学性能。特别是添加8%的纳米ZrO_2和20%的PEEK能使PTFE复合材料同时获得最佳的耐磨性(1.29×10~(-6) mm~3/Nm)和较低的摩擦系数。在摩擦试验的后期PTFE复合材料的瞬时磨损率突然急剧上升。根据瞬时磨损率、磨损表面、转移膜形貌和磨屑形态特征的变化规律,将整个磨损过程分为3个阶段(低磨损阶段、过渡磨损阶段和严重磨损阶段)。     

热塑性聚氨酯/尼龙6复合材料高载荷磨损性能及机理

通过熔融共混制备了热塑性聚氨酯(TPU)/尼龙6(PA6)复合材料,利用摩擦实验研究了PA6及其复合材料的高载荷磨损性能。结果表明,纯PA6在摩擦过程中不能形成转移膜,短时间内被磨穿,TPU/PA6复合材料由于形成稳定的转移膜,大幅度提高了其在高载荷下的耐磨性。材料磨损面的扫描电子显微镜(SEM)分析结果表明,纯PA6在高载荷下的磨损机理以疲劳磨损和粘着磨损为主,TPU/PA6复合材料的磨损机理主要表现为粘着磨损、疲劳磨损及氧化磨损。     

碳纤维及石墨填充聚四氟乙烯复合材料的摩擦学性能研究

利用M-200型环-块摩擦磨损试验机对石墨(Gr.)及碳纤维(CF)填充聚四氟乙烯(PTFE)复合材料的摩擦磨损性能进行了研究,探讨了石墨及碳纤维的协同润滑效应.认为碳纤维的加入大大提高了复合材料的承载能力,石墨的加入减小了碳纤维表面与对偶的摩擦系数,从而降低了碳纤维的脱落趋势,提高了复合材料的耐磨性.利用扫描电子显微镜(SEM)对PTFE复合材料的摩擦面及对偶转移膜进行了观察.结果表明,本实验中20%的石墨和10%碳纤维填充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.     

Hybrid effect of nanoparticles with carbon fibers on the mechanical and wear properties of polymer composites

Polyetheretherketone (PEEK) composites reinforced with carbon fibers (CFs) and nano-ZrO₂ particles were prepared by incorporating nanoparticles into PEEK/CF composites via twin-screw extrusion. The effects of nanoparticles on the mechanical and wear properties of the PEEK/CF composites were studied. The results showed that the incorporation of nano-ZrO₂ particles with carbon fiber could effectively enhance the tensile properties of the composites. The tensile strength and Young’s modulus of the composites increased with the increasing nano-ZrO₂ content. The enhancement effect of the particle was more significant in the hybrid reinforced composites. The compounding of the two fillers also remarkably improved the wear resistance of the composites under water condition especially under high pressures. It was revealed that the excellent wear resistance of the PEEK/CF/ZrO₂ composites was due to a synergy effect between the nano-ZrO₂ particles and CF. CF carried the majority of load during sliding process and prevented severe wear to the matrix. The incorporation of nano-ZrO₂ effectively inhibited the CF failures through reducing the stress concentration on the carbon fibers interface and the shear stress between two sliding surfaces. It was also indicated that the wear rates of the hybrid composites decreased with the increasing applied load and sliding distance under water lubrication. And low friction coefficient and low wear rate could be achieved at high sliding velocity.     

Effect of hot water immersion on the performance of carbon reinforced unidirectional poly(ether ether ketone) (PEEK) composites: Stress rupture under end-loaded bending

This paper describes the behaviour of AS4 and T700SC reinforced PEEK composites (SUPreM™ and ACP-2) under applied compressive bending strain. The effect of an increased molecular weight of the polymer matrix on the residual time under endloaded compression bending conditions is studied. Generally for a given composite material, the higher the testing temperature and the applied strain the faster the failure occurs. At test temperatures exceeding the glass transition temperature or at high strain ratios the time-to-failure for CF/PEEK composites follows a master curve. The residual times under endloaded compression bending conditions increase with increasing toughness of the PEEK matrix but decrease with increasing tensile strength of the reinforcing fibres. It seems that the better the fibre/matrix adhesion the lower is the time to failure of an endloaded composite, because more load is transferred from the matrix into the fibres.In order to simulate composite applications under ‘harsh’ conditions the CF/PEEK composites have been exposed to boiling water. PEEK is known to be highly resistant to environmental effects, but water uptake significantly influences the overall performance of CF/PEEK composites under endloaded compression bending conditions. The tensile properties of the composites have been measured as function of exposure time in boiling water. The fibre dominated uniaxial tensile strength is not/or only slightly affected by the boiling water conditioning even after extended exposure times but the transverse tensile strength decreases significantly after exposure to boiling water. The performance of SUPreM™ CF/PEEK-150 and 450 composites under endloaded compression bending conditions are positively affected by water conditioning whereas APC-2 fails at shorter residual times. The fracture behaviour under endloaded conditions is also affected by the ingress of water into the composite.The obtained results show clearly that applications of thermoplastic composites leading to large out of plane deformations can only be ‘safe’ if the maximum service temperatures of the finished part will be well below the glass transition temperature of the polymer matrix otherwise even at low bending radii a dramatic failure of the material cannot be excluded.     

Influence of cooling rate on interlaminar fracture properties of unidirectional commingled CF/PEEK composites

The influence of cooling rates on the mechanical property profile (transverse flexure properties and modes-I and -II interlaminar fracture toughness) has been investigated for unidirectional commingled CF/PEEK composites. A laboratory hot press with a steel mould was used to process the composites at 400°C for 60 min, at an applied pressure of 1 MPa. Cooling rates from fast (quenching in oil) to slow (hot press cooling) were achieved at ambient pressure. The results indicate that different matrix morphology was found at different cooling conditions, although deconsolidation occurred in the CF/PEEK composites during cooling. When the cooling rate was shifted from slow to fast, consolidation quality of the CF/PEEK composites was improved. The resulting effect of the consolidation quality and cooling rates on the mechanical property profile of commingled CF/PEEK composites is presented. It was found that the effect of the cooling rate on the mechanical property profile of the commingled CF/PEEK composites could not be isolated from the consolidation quality.     

碳纤维-AlN/聚醚醚酮复合材料的制备与性能

以聚醚醚酮(PEEK)为基体树脂、碳纤维(CF)和氮化铝(AlN)为填料,通过模压成型的方法制备了抗静电耐热型CF-AlN/PEEK复合材料。采用高阻计、导热系数测定仪、热失重、差示扫描量热仪和SEM研究了CF-AlN/PEEK复合材料的抗静电性能、热性能、力学性能以及降温速率对复合材料性能的影响,并探讨了后期热处理对力学性能的影响。结果表明:当CF和AlN的质量分数均为10%时,CF-AlN/PEEK复合材料的性能较优,其表面电阻率达到108 Ω,比PEEK的表面电阻率提高了6个数量级;导热系数为0.418 W·(m·K)-1,初始分解温度高达573℃;拉伸强度提高了40.4%;降温速率越低,复合材料的熔点越高;后期热处理会影响CF-AlN/PEEK复合材料的力学性能,在270℃下热处理2 h,其拉伸强度可达146 MPa,表明在生产过程中,加工温度是影响复合材料性能的因素之一。      

The mechanical properties of insert-molded poly (ether imide) (PEI)/C fiber poly (ether ether ketone)(PEEK) composites

The mechanical properties of insert-molded poly(ether imide) (PEI)/carbon fiber poly(etheretherketone) (CF PEEK) have been examined. Bimaterial composite specimens were constructed by injecting CF PEEK into a mold containing one-half of a PEI tensile specimen. These PEI/CF PEEK composites retained much of their strength and dimensional integrity at temperatures as high as 200°C. Variations in test speed had little affect on breaking strains or stiffness. For two grades of PEI examined, properties were independent of the molecular weight of the PEI. Ultimate properties and fracture surfaces suggested good adhesion between the PEI and CF PEEK, possibly aided by miscibility between the two materials. The PEI/CF PEEK bimaterial composites behaved similarly to PC/CF PEEK specimens, but exhibited higher breaking stresses and moduli, both at room and elevated temperatures.     

剪切载荷下温度和应变率对碳纤维增强聚醚醚酮复合材料强化行为的影响

碳纤维增强聚醚醚酮(CF/PEEK)是一种高性能热塑性复合材料,在航空航天领域有着广阔的应用前景。由于PEEK具有温度和应变率相关的非线性行为,导致CF/PEEK复合材料在基体主导的面内剪切方向也有类似的力学行为。本文在不同的温度和应变率下对CF/PEEK复合材料试件进行了剪切实验,将应力-应变曲线分为线性与非线性部分,发现温度和应变率对CF/PEEK复合材料的屈服应力有着较大的影响。随着温度从20℃升高到130℃屈服应力下降了66%左右,下降速度先快后慢,随着应变率从10?5 s?1提高到0.1 s?1屈服应力均匀增大了35%左右。将所得规律拟合背应力经验公式,修改了经典的热塑性复合材料本构模型的屈服函数。并编写VUMAT用户子程序对CF/PEEK复合材料剪切实验进行数值分析,与实验结果对比发现非线性阶段的剪切应力-应变关系及屈服点的剪切应力吻合良好,但是由于纤维和PEEK基体的浸润性较差,导致CF/PEEK复合材料内部存在孔隙缺陷,影响了CF/PEEK复合材料的初始剪切弹性行为,导致加载初始阶段存在偏差。      

纺织结构碳纤维增强聚醚醚酮基复合材料的制备及界面改性

采用热压成型法制备纺织结构碳纤维增强聚醚醚酮(CFF/PEEK)航空热塑性复合材料。通过对碳纤维(CF)进行去浆、活化,及采用磺化聚醚醚酮(SPEEK)进行表面涂层,显著提高了CFF/PEEK复合材料的层间剪切强度。讨论了热压温度、压力等工艺参数对材料综合力学性能的影响规律,确定优化工艺条件,制备的复合材料拉伸强度和弯曲强度分别达到714.29 MPa和955.84 MPa。借助扫描、金相显微镜等观察手段,发现经过界面改性处理后,复合材料断裂发生在基体内部而非界面处,基体与增强体浸润性和结合性良好。     

碳纤维增强聚醚醚酮复合材料的形状记忆效应

为推动形状记忆聚合物在空间等极端恶劣环境中的应用,以超薄碳纤维增强聚醚醚酮(Carbon fibers reinforced polyether-ether-ketone,CF/PEEK)预浸料为实验对象,采用薄膜叠层与热压成型工艺制备厚度为0.036 mm超薄预浸料的层合片材,研究了其在热应力驱动下的形状记忆行为。结果表明,在320℃加热-冷却热循环温度场的作用下,CF/PEEK复合材料超薄层合板的初始变形的形状回复率近似可达100%,当变形循环达到100次时,其形状回复率仍然可以保持在90%以上。此外,根据层合板变形的温度与应力-应变关系,解释了CF/PEEK复合材料的热应力驱动变形机制。在此基础上,改变CF/PEEK层合板厚度进行仿真设计,实现了初始状态与深海珊瑚形状、立方体、灯笼草形状之间的变形与回复。利用记忆变形产生的机械夹紧力,完成了硬币抓取实验,验证了CF/PEEK复合材料在主动变形结构应用的可行性。      

碳纤维/聚醚醚酮单向带各向异性导电行为的尺度效应

具有导电各向异性的高分子复合材料(ACPCs)在场发射装置及传感器设计领域具有重要应用。常规的ACPCs很难获得超大导电各向异性系数,且力学性能有限。本文采用碳纤维(CF)宽展、表面浸润与树脂复合一体化超薄热塑性单向带制备方法,制备厚度为0.04 mm和0.1 mm的CF增强聚醚醚酮(CF/PEEK)复合材料单向带,以PEEK纤维为纬线制备CF/PEEK复合材料单向编织布,采用热成型工艺制备CF/PEEK复合材料单向层合板。利用数字万用表和霍尔效应系统测试层合板面内及厚度方向的电阻率和面内的电子迁移率;采用超景深显微镜观察CF/PEEK复合材料单向层合板面内和厚度方向的纤维排列形貌。结果表明,超薄CF/PEEK复合材料单向层合板面内(纤维方向与横向)导电率之比高达377,而面内横向和厚度方向的导电率之比接近1,表明CF/PEEK复合材料获得了良好的横观各向同性;超薄化CF/PEEK复合材料的面内电子迁移行为同样具有巨大的各向异性,这一结果为CF/PEEK复合材料在场发射器件、传感器设计及其灵敏度调控方面提供了实验基础。      

Effects of potassium titanate whiskers and carbon fibers on the wear behavior of polyetheretherketone composite under water lubricated condition

The tribological behaviors of polyetheretherketone (PEEK) composite reinforced by carbon fiber (CF) and potassium titanate whiskers (PTW) have been investigated using the pin-on-disk configuration at different applied loads under water lubricated condition. The effects of micrometer carbon fiber and sub-micrometer PTW on the wear properties of the hybrid composite have been discussed. It was found that the PEEK/PTW/CF composite showed excellent tribological performance in water condition. High wear resistance and low friction coefficient were achieved under a wide range of loads. It was revealed that the two fillers worked synergetically to enhance the wear resistance of the hybrid reinforced PEEK composite. The carbon fiber carried the main load between the contact surfaces and protected the matrix from further severe abrasion of the counterpart. At the same time, the exposed PTW out of the polymer matrix around the fiber inhibited the direct scraping between the fiber edge and counterpart tip in some degree, so that the fibers could be less directly impacted during the subsequent sliding process and they were protected from severe damage. In addition, the reinforcement effect of PTW on PEEK could reduce the stress concentration on the carbon fiber-matrix interface, and thereby reduce the CF failure/damage. The reinforcement effect of PTW on PEEK might also restrict the crack initiation and propagation on the surface and subsurface of the composite, and therefore to protect the matrix from fatigue failure during the sliding process.