含纳米CuO锂基润滑脂摩擦学性能研究

为改善锂基润滑脂摩擦学性能,制备不同添加量纳米CuO改性的锂基润滑脂。采用3H-2000PS2比表面及微孔分析仪对纳米CuO粒子进行表征,采用四球摩擦磨损试验机分析纳米CuO添加量对锂基润滑脂摩擦学性能的影响,采用扫描电镜(SEM)和三维形貌分析仪分析试验后钢球磨痕形貌。结果表明:纳米CuO质量分数为0.60%时锂基润滑脂具有最佳的抗磨减摩效果,摩擦因数和磨斑直径较基础脂分别降低24%和12%;一定添加量下,纳米CuO对磨损表面具有修复作用,含质量分数0.60%纳米氧化铜的润滑脂润滑时,磨损表面具有较低的表面粗糙度和较少的犁沟,表现出最佳的抗磨性能。     

含纳米PTFE颗粒润滑脂的润滑性能研究

在四球摩擦磨损试验机上考察纳米PTFE颗粒作为添加剂对复合钛基润滑脂摩擦磨损性能的影响,采用扫描电子显微镜分析试验钢球磨斑的表面形貌,并利用X射线光电子能谱仪检测磨斑表面化学元素的组成及状态。结果表明,在一定添加量范围内,纳米PTFE可以改善复合钛基润滑脂的摩擦磨损性能,其中纳米PTFE质量分数为3%时,复合钛基润滑脂具有最佳的抗磨、减摩性能,可使摩擦因数、磨斑直径分别降低约25.4%和18.9%。纳米PTFE颗粒在钢球表面发生摩擦化学反应,生成了一层金属氟化物,有效地抑制了摩擦表面的黏着磨损和接触疲劳。     

含超细SiO_2/MoS_2粉锂基润滑脂摩擦学性能研究

采用四球摩擦磨损试验机研究了纳米SiO_2及超细MoS_2的粒径、添加量和载荷对2~#锂基脂摩擦学性能的影响,并研究了2种超细粉复配比例和载荷对2~#锂基脂摩擦学性能的影响。结果表明:单一纳米SiO_2和超细MoS_2的加入均能明显减小润滑脂的摩擦因数和钢球磨斑直径,纳米SiO_2和超细MoS_2的复配有助于进一步改善含超细粉锂基脂的摩擦学性能。当纳米SiO_2与MoS_2质量比为2∶8,总加入质量分数为2.0%时,润滑脂的摩擦因数和钢球磨斑直径较基础脂分别减小了77.1%和46.42%。利用SEM和EDS分析磨斑表面形貌及元素组成,初步探讨了含超细复合粉润滑脂的抗磨减摩机理。SEM和EDS分析表明:纳米SiO_2在摩擦过程中主要作用是填补磨痕沟壑,而超细MoS_2除填补沟壑外还对摩擦副表面有抛光研磨和形成减摩膜的作用,2种超细粉的协同使润滑脂具有自修复和抗磨、减摩作用。     

油胺修饰镍纳米粒子在锂基脂中的摩擦学性能*

为提高镍纳米粒子作为润滑脂添加剂的减摩和抗磨能力,采用油胺对其进行修饰以减少团聚,通过SEM、FT-IR和XRD对OA-Ni的微观形态和结构进行了表征,利用四球摩擦试验机和TE77往复摩擦试验机考察表面修饰的镍纳米粒子(OA-Ni)对锂基润滑脂摩擦学性能的影响,并探讨其在润滑脂中的减摩抗磨机制。结果表明:制备的油胺修饰镍纳米粒子呈不规则的圆片状,粒径约为100 nm,在润滑脂中有良好的分散性;经油胺表面改性的镍纳米粒子能有效改善锂基脂的摩擦学性能,抗磨和减摩性能分别提升了36.6%和15%。磨损表面分析结果表明,在摩擦过程中油胺修饰的镍纳米粒子在摩擦表面形成了主要成分为Fe2O3、 Fe3O4、NiO、Ni2O3等金属氧化物的摩擦化学膜,提高了锂基脂的摩擦学性能。     

纳米锌填充超高分子量聚乙烯复合材料微动摩擦磨损性能

利用热压烧结法制备不同含量纳米锌填充超高分子量聚乙烯(UHMWPE)复合材料,采用微动摩擦磨损试验机研究干摩擦条件下纳米锌含量对复合材料微动摩擦磨损性能的影响。利用场发射扫描电子显微对复合材料断面进行分析,采用扫描电子显微镜对材料磨损表面及钢球进行表征,探讨复合材料的磨损机制。研究结果表明:随着纳米Zn含量的增加,复合材料的摩擦因数和磨损率均表现为先降低后升高;当纳米Zn质量分数为1%时复合材料具有最低的摩擦因数和磨损率,且对偶钢球表面形成连续的转移膜;复合材料的磨损机制主要为黏着磨损和磨粒磨损。添加锌纳米颗粒,可以提高UHMWPE复合材料的微动摩擦磨损性能,当纳米锌质量分数为1%时,复合材料具有最低的摩擦因数和最优的耐磨损性能。     

润滑脂对膨胀管材料摩擦性能的影响

膨胀管膨胀过程中的摩擦影响到膨胀的难易程度和胀后套管的性能,选择一种合适的润滑介质降低膨胀过程中的摩擦因数对膨胀管技术来说非常重要。使用摩擦模拟实验的方法,研究在二硫化钼锂基脂、铅基润滑脂和没有润滑脂的3种条件下普通N80膨胀管材料的摩擦性能,使用扫描电子显微镜对不同载荷下试样的磨损表面进行分析,并讨论不同润滑条件下的磨损机制。结果表明,润滑脂的加入可以显著降低膨胀过程中膨胀管材料的摩擦因数和磨损量,磨损机制也从原来的磨粒磨损变成黏着磨损,铅基润滑脂由于摩擦因数更低具有最好的润滑效果,可以显著提高膨胀管材料在膨胀过程中的耐磨性能。     

几种纳米粒子作为润滑脂修复添加剂的试验研究

在MRH-3高速环块摩擦磨损实验机上,研究了纳米微粒Cu,Al,Al2O3,MgO加入到通用锂基脂中的摩擦学性能。并采用扫描电子显微镜,能量色散谱仪分析了摩擦表面的形貌和元素组成。结果表明:含有纳米Cu,Al,Al2O3,MgO粒子的润滑脂对摩擦表面均有很好的减摩和修复能力,但各种粒子的效果有所不同,其中Al2O3,Cu,Al3种粒子要比MgO具有更好的效果。     

硅烷修饰二氧化硅微球的制备及其摩擦性能

根据St9ber法制备5种不同粒径的有机-无机二氧化硅微球;采用扫描电子显微镜对微球的表面形貌进行表征分析;在四球摩擦磨损实验机上考察微球作为添加剂对润滑油摩擦磨损性能的影响,采用扫描电子显微镜分析试验钢球磨斑的表面形貌,利用能谱仪检测磨斑表面化学元素的组成,并讨论有机-无机二氧化硅微球的减摩抗磨机制。结果表明,在一定添加范围内,纳米级别的二氧化硅微球可以改善润滑油的摩擦磨损性能。有机-无机二氧化硅微球在钢球表面起填埋和抛光作用,有效地抑制了摩擦表面的黏着磨损和接触疲劳。     

高速铁路轴箱轴承纳米润滑脂摩擦学性能试验研究

以WS2和Si3N4纳米颗粒作为高速客车轴箱轴承润滑脂添加剂,依据完全析因试验方案,合成了高速客车轴箱轴承纳米润滑脂。采用四球摩擦磨损试验机对其抗磨减摩和抗极压性能进行了研究,使用扫描电子显微镜(SEM)分析了钢球磨斑表面形貌,运用双因素方差分析法探究了WS2-Si3N4复合纳米颗粒对纳米润滑脂润滑性能影响。研究表明:当WS2添加量为1.5%,Si3N4添加量为0.1%时,合成的纳米润滑脂PB值最大,摩擦因数最低,钢球磨斑形貌平整光滑;WS2和Si3N4纳米颗粒均可提高纳米润滑脂的润滑性能,对复合纳米润滑脂润滑性能的提高交互作用显著。     

润滑介质对摩擦性能影响差异分析

L-CKD150润滑油和复合锂基润滑脂广泛运用于石油装备润滑减磨。为研究2种润滑介质对摩擦副摩擦磨损性能及磨损机制的影响差异,采用MMW-1型微机控制立式万能摩擦磨损试验机,开展不同接触压力和线速度及不同润滑环境下摩擦学实验研究。结果表明:实验工况下,销-盘摩擦副表面以磨粒磨损为主,同时存在黏着磨损;相比于L-CKD150润滑工况,复合锂基润滑脂润滑时销-盘表面黏着磨损更为严重,进而加大摩擦因数的波动幅度,最大波动幅度为L-CKD150润滑下的3.7倍;盘试样表面磨粒磨损与接触压力有关,0.5 MPa接触压力下,L-CKD150润滑时磨粒磨损较严重,1.5 MPa下则复合锂基润滑脂润滑时更严重,磨粒磨损是影响盘试样磨损量差异的主要因素。     

Influence of Polyfluo-Wax on the Friction and Wear Behavior of Polyimide/Epoxy Resin–Molybdenum Disulfide Bonded Solid Lubricant Coating

Polyimide/Epoxy resin–molybdenum disulfide bonded solid lubricant coatings (denoted as PI/EP-MoS₂) were prepared. The influence of polyfluo-wax (denoted as PFW) on the microhardness and friction and wear behavior of as-prepared PI/EP-MoS₂ lubricant coating was measured using a microhardness tester and a reciprocating ball-on-disc tribometer, respectively. The worn surfaces of the lubricant coatings were observed with a scanning electron microscope, and their wear rate was determined with a Micro XAM surface mapping microscope. Moreover, the transfer films formed on the counterpart steel ball surfaces were analyzed by X-ray photoelectron spectroscopy. Results indicate that the incorporation of a proper content of PFW filler is effective at improving the antifriction performance of the PI/EP-MoS₂ lubricant coating while maintaining better wear resistance. Moreover, the friction coefficient of the lubricant coating decreases with increasing content of PFW from 2 to 10%, and the one with a filler content over 6% PFW has a steady friction coefficient of 0.07. The improvement in the antifriction performance of the lubricant coating with the incorporation of the PFW filler is attributed to the excellent lubricity of homogeneously distributed PFW.     

纳米SiO2颗粒和玻璃微珠共混改性超高分子量聚乙烯复合材料的摩擦磨损性能

采用模压成型工艺制备了纳米SiO2颗粒和玻璃微珠共混改性的超高分子量聚乙烯复合材料;研究了相对滑动速度、载荷以及玻璃微珠含量对复合材料摩擦磨损性能的影响,并对磨损形貌和磨损机理进行了分析。结果表明:添加纳米SiO2颗粒和玻璃微珠可以提高复合材料的硬度、压缩弹性模量和摩擦磨损性能;相对滑动速度对复合材料摩擦因数和磨损率有很大的影响;载荷对复合材料的摩擦因数影响不明显,但磨损率随载荷的增加而增大;纳米SiO2颗粒和玻璃微珠混合改性后复合材料的磨损机理主要是粘着磨损和疲劳磨损。     

花状与球状MoS2对PAO15润滑油摩擦学性能的影响

为改善低黏度PAO15润滑油的摩擦学性能,通过水热法制备球形与花状MoS_2颗粒,采用X射线衍射仪(XRD)与扫描电子显微镜(SEM)对所制备的MoS_2颗粒进行表征。制备球形与花状MoS_2改性的PAO15油,利用四球摩擦试验机对比研究2种形貌MoS_2在不同用量条件下对PAO15油摩擦学性能的影响。采用光学显微镜、表面轮廓仪、扫描电子显微镜(SEM)与能谱仪(EDS)对磨痕表面进行表征。结果表明:制备的球形与花状MoS_2晶型均较好地符合MoS_2的晶型,掺杂至PAO15油中均能够提升其摩擦学性能,使其摩擦因数降低;随着MoS_2颗粒添加量的增加,PAO15油摩擦学性能有所提升,在质量分数为1.0%时达到最优;花状MoS_2具有更大的比表面积,其对PAO15油抗磨损性能的提升优于球形MoS_2,形成的转移膜能够更好地起到隔离摩擦表面的作用。     

Effect of Particle Concentration on Tribological Properties of ZnO Nanofluids

In this research, oleic acid surface-modified ZnO nanoparticles were successfully dispersed into 60SN base oil. The distribution of ZnO nanoparticles in the lubricant was tested by transmission electron microscopy. The friction and wear properties of nanofluids were evaluated with a four-ball tester, and the morphologies of wear scars were measured by a scanning electron microscope (SEM) and a surface profiler. Results show that oleic acid can improve the stability of ZnO nanoparticles in the lubricant; oil-based nanofluids with ZnO nanoparticles could remarkably reduce friction and wear. When the amount of oleic acid added was 8 wt% and ZnO nanoparticles was 0.5 wt%, the coefficient of friction and average diameter of the wear scars were minimum and the fluid exhibited better friction-reducing and antiwear properties.     

The Size Effect of Boron Nitride Particles on the Tribological Performance of Biolubricants for Energy Conservation and Sustainability

The size of particulate additives in a bio-based lubricant influences their friction and wear performance during sliding contact. The present investigation evaluates the effect of boron nitride particle size on the tribological performance of canola oil-based lubricant mixtures. During sliding experiments, micron-, submicron-, and nanometer-sized boron nitride particle additives were considered. Friction and wear measurements were carried out on the prepared lubricant mixtures using a pin-on-disk tribometer at ambient conditions. A scanning electron microscope and optical profilometer were used for topographical studies to evaluate the influence of particle size on wear damage and surface roughness. The results revealed that the nanometer-sized particulate mixture outperformed micron- and submicron-sized particulate combinations in terms of friction and wear performance and provided a 90 % smoother surface finish. Furthermore, the tribological response of canola oil containing micron- or submicron-sized particles was found to be significantly enhanced by the addition of nano-sized particles, where the friction and wear were reduced by 40 and 70 %, respectively. It was inferred that the nano-sized particles were able to better coalesce in the asperity valleys due to their small size and spherical shape, which provided them with enhanced tribological properties in comparison with the micron- and submicron-sized particles that were larger and exhibited a plate-shaped in geometry. Newly developed non-dimensional surface roughness parameters were introduced to quantify the influence of particle size and the mechanisms involved in the tribological phenomena. The state of lubricants derived from bio-based feedstock were subsequently explored for their influence on energy conservation and sustainability, as well as their potential impact on the lubricant market place.     

Tribological Properties of Friction Pairs in Lubricant Contaminated with Particles under High Temperature

A liquid–solid lubricant with sand particles of different sizes and concentrations is prepared in advance. The viscosity of the lubricant is measured by a capillary viscometer to determine its relationship to the concentration or size of the sand particles. The relationships between friction and concentration or size of the sand particles are also identified with a UMT2 tribometer. Results indicate that the size of sand particles plays an important role in the lubrication performance; when the size of sand particles is 1–5 μm, the friction coefficient of the liquid–solid lubricant is reduced at low concentration and low load. Contaminant concentration greatly influences the tribological behavior of such a lubricant. The failure probability of the part surface decreases with a reduction in particle concentration; moreover, a high temperature aggravates the friction and wear of this surface. The friction coefficient is 0.14 at 200°C, which is well above the friction coefficient at room temperature (0.078), and the wear volume also increases by 30% compared to the normal temperature. When the temperature is 300°C the wear volume is two times that under room temperature.     

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。     

不同组分比的坡缕石-铜复合纳米颗粒的摩擦学性能研究

将制备的不同组分比的坡缕石/铜复合纳米材料作为润滑添加剂在MMU-10G摩擦磨损试验机上测试其摩擦学性能,使用XJL-03倒置式金相显微镜和Genesis能谱仪对测试铸铁试样的磨损表面进行形貌观察和元素分析。结果表明:不同组分比的坡缕石铜润滑添加剂都具有一定的减摩抗磨效果,与基础油相比,摩擦因数最多下降了72.2%,试件磨损失重最多减少了90.6%;对磨试件的磨损失重量随着复合材料中铜组分的增加呈直线下降;而摩擦因数先随着铜组分的增加而缓慢上升,后急剧增大。     

镶嵌MoS2的Al2O3/TiC基陶瓷刀具材料微孔表面摩擦磨损性能研究

采用Nd:YAG激光器在Al2O3/TiC陶瓷刀具材料表面加工出不同密度的微孔,并涂覆填装MoS2固体润滑剂,在UMT-2摩擦磨损试验机上进行往复摩擦试验,研究其在不同载荷和速度下的摩擦磨损性能,通过白光干涉仪、光学显微镜和扫描电镜观察激光织构化后表面特征和磨损后表面形貌。结果表明:激光织构化后,陶瓷材料表面发生了氧化;在相同的实验条件下,与光滑表面相比较,填装MoS2固体润滑剂的微孔表面能够有效地降低摩擦因数,减小磨损率。这主要是由于填装在微孔中的润滑剂在摩擦作用下涂覆到基体表面,形成润滑膜,起到减摩降磨作用,同时激光加工后微孔周围凸起及氧化后形成的摩擦特性优良的TiO2也能起到良好的减摩降磨效果。通过对磨损形貌分析,光滑表面磨损较为严重,有大量的犁沟产生,主要的磨损形式为磨粒磨损及脆性断裂;微孔表面磨损较为轻微,其主要磨损发生在微孔周围。     

纳米HA增强PVA-H复合材料的摩擦学性能研究

利用四球试验机考察了纳米羟基磷灰石（HA）粉体增强PVA-H人工软骨材料与不锈钢球进行对磨时的摩擦磨损性能，采用扫描电子显微镜（SEM）观察并分析了磨损表面的微观形貌。试验结果表明：加入适量的纳米HA（质量分数1％）能有效地降低复合材料的摩擦因数，但更多的添加量反而增加复合材料的摩擦冈数；SEM图像表明，纯PVA-H的表面有较严重的磨损痕迹和磨屑，而HA粒子的加入可以降低复合材料表面的磨损情况。