浸渗型TiC/FeCrWMoV金属陶瓷高温自润滑特性及其润滑机理

采用熔融固体润滑剂和微孔金属陶瓷预制体的真空压力浸渗复合技术,制备出浸渗型互穿网络结构TiC/FeCrWMoV系高温自润滑复合材料。利用XP型高温摩擦磨损试验机考察其摩擦磨损性能,运用扫描电子显微镜(SEM)、光电子能谱(EDXA)和X射线衍射(XRD)分析磨损表面成分、形貌和结构,探讨了该材料的高温自润滑机理。结果表明:高温摩擦磨损过程中,浸渗于复合材料微孔中的固体润滑剂扩散析出,并在摩擦表面形成含有PbWO4、PbO、SnWO4、Ag2WO4、Ag3Sn等氧化物和金属间化合物的润滑膜是其在高温下具有良好自润滑性能的主要原因;摩擦界面的微孔结构是影响浸渗复合式高温自润滑材料摩擦过程中润滑膜完整性的主要因素。Pb-Sn-RE三元系复合固体润滑剂中加入Ag元素可以防止润滑膜表层开口孔隙的封闭,有助于浸渗复合式高温自润滑复合材料孔隙中固体润滑剂的持续扩散析出,以保证摩擦磨损过程中润滑膜的持久性和完整性。     

水润滑轴承用聚合物复合材料的摩擦学研究进展

聚合物复合材料因其优异的自润滑、高化学稳定性和减振降噪等特性而备受关注。以水作为工作介质的水润滑轴承具有环境友好、维护成本低及结构设计简单等特点,已被广泛应用于船舶、水电和化工等领域。首先总结了水润滑轴承用聚合物复合材料特性,归纳了聚合物复合材料在水润滑条件下的摩擦学性能及磨损机制,介绍了提高聚合物复合材料摩擦学性能的常规方法,并进一步探讨了材料内部结构、摩擦界面微观结构与材料宏观摩擦学特性的内在关联。指出促进水润滑聚合物-金属配副摩擦界面原位生长固体润滑特性转移膜,可弥补水膜润滑能力不足、显著提高配副的摩擦学性能,深入研究水润滑状态下复合材料的微观摩擦磨损机制,对于理解水润滑配副的摩擦学机理有重要的意义。     

Fe-Mo-(MoS2/PbO)高温自润滑材料的摩擦学特性

采用粉末冶金热压烧结工艺制备了一种在高温下具有良好摩擦学性能的Fe-Mo-(MoS2/PbO)自润滑材料,考察了其在室温和600℃下的摩擦磨损性能,并运用扫描电子显微镜(SEM)、X射线光电子能谱(XPS),X射线衍射(XRD)等分析手段揭示了Fe-Mo-(MoS2/PbO)高温自润滑材料的摩擦磨损机理.研究结果表明:由于摩擦和高温氧化作用,该类材料在600℃下磨损表面的复合润滑膜(由PbMoO4、Pb、Fe2O3和Fe3O4组成)是其具有良好自润滑性能的主要原因.     

高分子自润滑材料研究进展

高分子自润滑材料的基础和应用研究是摩擦学研究的热点之一.介绍了高分子基复合材料的磨损机理研究及固体润滑剂的发展和应用研究状况,综述了聚四氟乙烯(PTFE)、聚酰亚胺(PI)、聚醚醚酮(PEEK)、聚苯硫醚(PPS)、聚甲醛(POM)作为自润滑材料的研究应用进展,无机填料主要提高其硬度与耐磨性,而聚合物共混可改善纯树脂的热力学性能,复合材料摩擦磨损特性与在对偶面上形成转移膜的能力和转移膜特性相关.     

聚四氟乙烯/碳纤维增强聚酰亚胺复合体系的摩擦学性能

研究评价了不同PTFE含量的碳纤维增强P1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2种不同条件下的磨损表面形貌和磨损机理。研究表明：PTFE以10%添加时PI/CF/PTFE体系的机械性能最佳，而摩擦学性能以5%添加为佳；随PTFE含量的增加，复合材料的摩擦系数降低，磨损率增加。水润滑下，摩擦系数和磨损率比干摩擦下的都有相应的降低。干摩擦下，材料的磨损均以塑性变形、微观破裂及破碎为主导；水润滑下，这一机制显著减弱，归因于水的润滑和冷却作用。     

自润滑材料及其摩擦特性的影响因素

自润滑复合材料是材料科学研究领域的一个重要发展方向,由于其在特殊使用条件下具有优良的摩擦学特性而受到人们的广泛关注。综合介绍与评述了国内外自润滑复合材料的开发与进展,讨论了对材料摩擦学性能的影响因素,提出了在今后研究与开发工作中应当重视的几个努力方向。     

CNTs/NbSe_2/Cu基自润滑复合材料的制备及其摩擦学性能研究

将CNTs、Se粉和Nb粉按一定化学计量比均匀混合,通过固相反应生成碳纳米管(CNTs)/NbSe2复合材料,然后以生成的CNTs/NbSe2复合材料为固体润滑相,Cu为基体相,通过粉末冶金的方法制备出了CNTs/NbSe2/Cu基自润滑复合材料。利用UMT-2摩擦磨损试验机对材料的摩擦磨损性能进行评价,结果表明NbSe2/Cu基自润滑复合材料具有较好的摩擦学性能,磨痕平滑;随着1%(质量比)CNTs的加入,CNTs/NbSe2/Cu基自润滑复合材料摩擦学性能更为优异,其磨痕更平滑。这是由于具有优异润滑性能的NbSe2和均匀弥散分布在Cu基体中的大长径比管状结构的CNTs一起起到了协同强化和减摩耐磨作用,最终导致材料的机械和摩擦学性能同时提高。     

关节轴承自润滑材料摩擦学性能及轴承寿命预测研究现状

自润滑关节轴承由于具有结构简单、承载能力强、适应温度范围广、在服役过程中无需添加润滑剂等特点,被广泛应用在航空航天、水利电力、军工机械等行业.与此同时,高端、精密、大型装备的发展对自润滑关节轴承的摩擦学性能、使用寿命和可靠性提出了更高的要求.自润滑关节轴承所使用的自润滑材料性能直接决定了轴承的寿命和性能水平,因此开展对自润滑材料性能的研究成为提高自润滑关节轴承质量和延长其寿命的关键.目前,自润滑衬垫材料大致分为三种,即金属背衬层状复合材料、聚合物及其填充复合材料和PTFE纤维织物复合材料.自润滑衬垫材料的摩擦学性能、衬垫粘结前的处理方式、粘结方式、编织纹路等因素影响着自润滑关节轴承的使用性能.因此,国内外研究者们选择合适的纤维、纳米金属颗粒和PTFE进行复合,大幅改善了自润滑材料的摩擦学性能;同时对衬垫材料的编织结构、捻制方式以及与轴承的粘结方式进行优化研究.为进一步探究衬垫材料的磨损失效机理,国内外研究者通过轴承磨损试验和有限元仿真相结合的方法研究轴承服役过程中的磨损机理、磨损失效规律和静态接触等问题.研究发现,固体润滑转移膜的持续形成能力是自润滑衬垫材料润滑性能和耐磨性能的决定因素.自润滑关节轴承在服役过程中的磨损形式主要为黏着磨损、磨粒磨损,并伴随一定程度的疲劳磨损.为进行自润滑关节轴承的寿命预测和可靠性分析,国内外研究者们通过研制轴承寿命试验平台,以磨损量为反映关节轴承磨损寿命的主要物理量,建立了大量的磨损寿命分布函数,同时,推导出一系列考虑轴承自身结构特点、润滑方式和工况条件的寿命预测公式并进行可靠性分析.本文以自润滑关节轴承常用的PTFE纤维织物衬垫材料作为主要讨论对象,综述了衬垫材料的组分、编织结构、粘结性能对其摩擦磨损行为的影响;讨论了衬垫型自润滑关节轴承服役过程中的转移膜形成机理及摩擦磨损行为,以及自润滑关节轴承寿命研究方法及试验平台的研制情况;通过对现有自润滑关节轴承寿命评估和可靠性研究现状分析,指出国内建立自润滑关节轴承寿命评估相应标准和试验规范的迫切性,以及对自润滑关节轴承可靠性研究的必要性.     

固体润滑剂对芳纶纤维增强尼龙66材料摩擦学性能的影响

本文研究了PTFE和MoS2两种固体润滑剂对芳纶纤维(AF)增强尼龙66(PA66)复合材料摩擦磨损性能的影响,进行了摩擦学测试,利用扫描电镜对其磨损微观形貌进行分析.结果表明,PTFE有效改善了复合材料的摩擦学性能,降低了材料的摩擦系数,提高了耐磨性;MoS2的加入并未改善其摩擦学性能.XPS分析表明:MoS2在摩擦过程中发生摩擦化学反应,生成了MoO3,产生严重的磨粒磨损.     

CaF2-MoS2铁镍基自润滑复合材料的摩擦学性能研究

以不同含量的MoS2、CaF2为润滑相,加入Cu、Fe和合金等元素,采用粉末冶金烧结工艺制备了具有在室温和高温下均有自润滑作用的铁镍基复合材料.采用UMT-2摩擦磨损试验仪、扫描电镜以及X射线衍射测试并分析了复合材料的摩擦磨损性能以及机理.结果表明,随着MoS2含量的减少、CaF2含量的增加,在室温时摩擦系数、磨损率均增大;而高温时摩擦系数、磨损率先降低后增大.当MoS2、CaF2各含3％(质量百分数)时复合材料在室温和高温时拥有最佳的摩擦性能.该复合材料室温时主要是MoS2起润滑作用,降低材料的摩擦磨损;而高温时MoS2、CaF2与金属相互作用生成CrxSx+1以及MoO2、CaMoO4、Fe2O3、FeMo4F6等物质,这些物质在摩擦表面形成复合润滑膜而起润滑作用.     

Friction and wear properties of UHMWPE composites reinforced with carbon fiber

The artificial joint acetabular material ultrahigh molecular weight polyethylene (UHMWPE) was reinforced with carbon fibers (CF) in different contents. The effects of CF content on hardness and tribological properties of the materials were studied. The morphologies of wear surfaces were examined with a Scanning Electron Microscope (SEM). The results show that the hardness and wear resistance of CF-reinforced UHMWPE composites increased with CF content; the friction coefficients under distilled water lubrication were decreased greatly by the addition of CF; that adherence, plowing, plastic deformation and fatigue wear are dominant for the UHMWPE under dry sliding, and that abrasive wear and drawing out of CF from the wear surface of the composites are dominant for the CF-UHMWPE composites under both dry and distilled water lubrication conditions.     

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.     

Friction and wear behavior of the polyurethane composites reinforced with potassium titanate whiskers under dry sliding and water lubrication

A series of polyurethane (PU)/potassium titanate whiskers (PTW) composites modified by a high molecular weight hydroxyl-terminated polydimethylsiloxane (HTPDMS) were prepared. The PTW is modified by 2,4-diisocyanatotoluene (2,4-TDI). The effect of the PTW content on the mechanical and tribological properties of the PU composites was studied. Tensile strength of the PU composites increased with the addition of PTW. The friction and wear experiments were tested on a MRH-3 model ring-on-block test rig at different sliding speeds and loads under dry sliding and water lubrication. Experimental results revealed that the small content of PTW contributed to largely improve the tribological properties of the PU composites. The coefficient of friction (COF) of the composites increased and the wear rate value decreased with increasing PTW. Scanning electron microscopic (SEM) investigations showed that the worn surfaces of the PTW-reinforced PU composites was smoother than pure polyurethane under given load and sliding speed.     

炭纤维增强聚醚醚酮复合材料在水润滑下的摩擦学行为

考察了炭纤维及PTFE增强PEEK复合材料在干摩擦和水润滑下的摩擦学性能,并研究了该复合材料在两种条件下的磨损机理.结果表明,干摩擦下复合材料的摩擦系数和磨损率随负荷的增加不断减小;水润滑下复合材料的摩擦系数随负荷的变化不大,磨损率随负荷的增加而增大.干摩擦下,复合材料的磨损以粘着磨损和磨粒磨损为主.水润滑条件下,磨损表面比较光滑,仅有微切削的痕迹,磨损方式以轻微磨粒磨损为主.干摩擦条件下,摩擦对偶表面仅有轻微的犁沟形成,表面形成一层薄而均匀且结合紧密的转移膜.水润滑下,对偶表面犁沟较深,犁削作用明显,转移膜的形成被明显抑制.水的冷却作用使得向摩擦对偶的粘着转移明显减轻,同时由于摩擦表面吸附水膜的边界润滑作用,显著改善复合材料的摩擦磨损性能.     

Friction and wear behavior of three-dimensional braided carbon fiber/epoxy composites under lubricated sliding conditions

The friction and wear characteristics of three-dimensional (3D) braided carbon fiber-epoxy (C_3D/EP) composites under lubricated sliding conditions against a quenched medium-carbon steel counterface were studied. Wear tests were performed under different loads at two velocities. Comparative wear tests under dry conditions were carried out to investigate the influence of lubrication. Tribological properties of the C_3D/EP composites with various fiber loadings and two different fiber-matrix adhesion strengths were assessed. It was found that the lubricated contact promoted lower wear rates and friction coefficients. Compared to dry sliding, the tribological performance of the C_3D/EP composites under lubrication was less dependent on fiber content, fiber-matrix bonding, load, and velocity than dry sliding. The worn surfaces of the C_3D/EP composites were analyzed by scanning electron microscopy (SEM) to explore the relevant mechanisms.     

The friction and wear properties of carbon nanotubes/graphite/carbon fabric reinforced phenolic polymer composites

In this paper, either graphite (Gr) or carbon nanotubes (CNTs), or both of them were incorporated into carbon fabric reinforced phenolic (CFRP) composites, preparing by a dip-coating and heat molding process, the tribological properties of the resulting composites were investigated using a block-on-ring arrangement. The worn surfaces were observed by scanning electron microscope to understand the mechanism. Experimental results showed that the optimal Gr was more beneficial than CNTs in improving the tribological properties of the CFRP composites when they were singly incorporated. It is well worth noting that the friction and wear behavior of the CNTs-filled CFRP composites were improved further when Gr was added, indicating that there is a synergistic effect between them. Tribological tests under different sliding conditions revealed that the Gr and CNTs-filled CFRP composites seemed to be the most suitable for tribological applications under higher sliding speed and load, and oil lubrication.     

Tribological properties of powder metallurgy – Processed aluminium self lubricating hybrid composites with SiC additions

In this experimental study, aluminium (Al)-based graphite (Gr) and silicon carbide (SiC) particle-reinforced, self-lubricating hybrid composite materials were manufactured by powder metallurgy. The tribological and mechanical properties of these composite materials were investigated under dry sliding conditions. The results of the tests revealed that the SiC-reinforced hybrid composites exhibited a lower wear loss compared to the unreinforced alloy and Al–Gr composites. It was found that with an increase in the SiC content, the wear resistance increased monotonically with hardness. The hybridisation of the two reinforcements also improved the wear resistance of the composites, especially under high sliding speeds. Additionally, the wear loss of the hybrid composites decreased with increasing applied load and sliding distance, and a low friction coefficient and low wear loss were achieved at high sliding speeds. The composite with 5 wt.% Gr and 20 wt.% SiC showed the greatest improvement in tribological performance. The wear mechanism was studied through worn surface and wear debris analysis as well as microscopic examination of the wear tracks. This study revealed that the addition of both a hard reinforcement (e.g., SiC) and soft reinforcement (e.g., graphite) significantly improves the wear resistance of aluminium composites. On the whole, these results indicate that the hybrid aluminium composites can be considered as an outstanding material where high strength and wear-resistant components are of major importance, predominantly in the aerospace and automotive engineering sectors.     

Study on the synergistic effect of carbon fiber and graphite and nanoparticle on the friction and wear behavior of polyimide composites

In this paper, the effect of short carbon fiber (SCF), graphite (Gr) and nano-Si₃N₄ on the friction and wear behavior of polyimide (PI) composites were studied using a block-on-ring arrangement. Experimental results revealed that single incorporation of SCF and Gr can improve the friction-reducing and anti-wear abilities of the PI composites significantly. However, nano-Si₃N₄ deteriorated the wear resistance of the PI composite drastically as single filler. A synergistic effect was found for the combination of nano-Si₃N₄ and SCF and Gr, which lead to the best tribological properties. It also can be found that the filled PI composites exhibited better tribological properties under higher PV product (the product of load and sliding speed). Moreover, the filled PI composites showed better tribological properties under oil lubrication and worse tribological properties under water lubrication compared with that under dry sliding condition.     

Fabrication of a nanocrystalline Ni-Co/CoO functionally graded layer with excellent electrochemical corrosion and tribological performance

Nanocrystalline (NC) Ni-Co/CoO functionally graded materials with excellent lubricating, high anti-corrosion and anti-wear performance were fabricated by electrodeposition and subsequent cyclic thermal oxidation and quenching. Transmission electron microscopy and energy dispersive x-ray spectroscopy investigations show that bulk Ni-Co gradient deposits with an average grain size in the range of 13-40?nm demonstrated a graded structure transition from face-centred cubic to hexagonal close packed and graded composition changes from Ni-rich to Co-rich regions with the increase in deposit thickness. X-ray diffraction and x-ray photoelectron spectroscopy analysis indicated the surface layer of NC Ni-Co graded materials to be mainly composed of dense and ultrafine CoO with a (111) preferred orientation. The NC Ni-Co/CoO functionally graded materials exhibited significantly enhanced corrosion resistance in both NaOH and NaCl solutions and remarkably improved wear resistance and dry self-lubricating performance when compared with the NC Ni and Ni-Co graded deposits under dry sliding wear conditions. The higher corrosion and tribological performance of NC Ni-Co/CoO graded materials can be attributed to the graded microstructure within the deposits, the anti-corrosion barrier of a dense oxide layer and the solid lubrication effect of CoO-rich tribo-surface films.     

三维编织复合材料在润滑条件下的摩擦性能

利用树脂传递模塑(RTM)工艺制备了三维编织炭纤维/环氧(C3D/EP)复合材料.采用MM-200型摩擦磨损试验机研究了该材料润滑条件下的摩擦磨损性能,探讨了载荷及滑动速度等外界因素的影响;并采用XL30 ESEM电子显微镜观察磨损表面形貌,分析了其磨损机理.结果表明,润滑条件下复合材料的摩擦磨损性能远优于干摩擦,且磨合期较短;随着载荷的增加,复合材料的摩擦系数和比磨损率降低,但滑动速度对摩擦磨损性能的影响很小;润滑条件下的磨损机理主要是磨粒磨损.