碳纳米管基膨润土润滑脂的制备及摩擦学性能研究

为制备摩擦学性能优良的多壁碳纳米管基膨润土润滑脂,采用油酸对多壁碳纳米管(MWCNTs)进行修饰,在实验室自主设计的超声辅助球磨试验装置上,制备在PAO6中均匀稳定分散的多壁碳纳米管悬浮液,并以悬浮液为基础油制备MWCNTs增强的膨润土润滑脂。探讨不同分散方法(球磨分散、超声分散、超声和球磨分散)对多壁碳纳米管分散稳定性的影响,研究润滑脂的摩擦因数、磨斑直径随多壁碳纳米管质量分数的变化。实验结果表明:经油酸修饰的多壁碳纳米管在超声和球磨综合作用下分散稳定性最好;随多壁碳纳米管质量分数的增加,膨润土润滑脂的摩擦因数、磨斑直径先减小后增大,其中多壁碳纳米管质量分数为0.03%时,所制备的膨润土润滑脂摩擦学性能最佳,磨斑直径最小(0.690 mm),比美孚28号航空润滑脂(符合美国军方规格MIL-G81322C,磨斑直径0.807 mm)降低了14.5%。     

纳米铜添加工艺对润滑油摩擦学性能的影响

探讨了纳米铜不同分散工艺和添加量对润滑油摩擦学性能的影响。分别采用超声分散和球磨分散工艺，将3种不同工艺制备的纳米铜材料溶于SF15W／40机油中，在T-11摩擦磨损试验机上进行摩擦学性能试验。结果表明，其中一种纳米铜能够提高基础油的减摩性能，采用超声分散比采用球磨分散的减摩性能好。随着纳米铜浓度的增加抗磨性能有明显的提高，分析认为纳米铜在摩擦表面的沉积有利于提高摩擦学性能。     

以汽油和甲醇为燃料时小型二冲程发动机摩擦特性比较

采用往复振动机模拟小型二冲程发动机运转工况，实验研究汽油和甲醇为燃料时发动机气缸和活塞环间的摩擦特性，并比较分别使用润滑油新油、润滑油老化油、润滑油新油和老化油的混合油作为润滑油时气缸和活塞环间的摩擦特性。结果表明，以甲醇为燃料时的摩擦因数和磨损量均小于以汽油为燃料时的摩擦因数和磨损量，特别是使用添加了润滑油新油的燃料时的摩擦因数和磨损量最小。通过黏度和热重（TG）分析，探讨甲醇燃料改善气缸和活塞环间的摩擦特性的原因，结果表明，甲醇燃料具有较高的黏度和较低的摩擦因数，因而以甲醇为燃料时可以降低磨损     

多壁碳纳米管改性UHMWPE的热膨胀和摩擦学性能研究

为了降低摩擦副用聚合物的热膨胀系数,用多壁碳纳米管(MWCNTs)改性超高分子量聚乙烯(UHM-WPE),通过热压成型法制备MWCNTs/UHMWPE复合材料.通过测量电导率计算渗流阈值来表征分散性;用热膨胀仪(DIL)测试复合材料的热膨胀率,并在干摩擦环境下,测试不同MWCNTs含量复合材料的摩擦学性能.结果表明:通...     

表面修饰的纳米金刚石微粒在润滑油中的抗磨减摩性

将纳米铁微粒、纳米铜微粒及纳米金刚石微粒分别分散到不含油性剂和极压抗磨添加剂的半成品合成润滑油中,采用MM-200型磨损实验机和XL30-1扫描电镜等设备研究了纳米微粒的抗磨减摩性,采用发动机台架试验研究了纳米金刚石的摩擦性能.结果表明,纳米金刚石微粒可明显改善润滑油的抗磨减摩性能;纳米金刚石润滑油的油膜有着非常好的抗黏滑能力和承载能力,对摩擦副有自修复作用.在普通发动机润滑油中加入质量分数0.01%的纳米金刚石微粒后,其润滑性能有很大的改善,在相同转速下功率平均提高4.2%;怠速时的HC排放量从8.75×10-4降低到3.50 ×10-4,降低60%,Nox排放量从1.66×10-4降低到1.32×10-4,降低20.5%;油缸的压力从0.441 Mpa增加到0.568MPa,相对增加28.9%;怠速也提高了19.6%.     

二维层状Ni/β-Ni(OH)2纳米复合材料的制备及其摩擦学性能研究

采用水热反应制备出β-Ni(OH)2,然后通过水热还原得到Ni/β-Ni(OH)2纳米复合粉体材料,采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对复合材料的相结构、成分及形貌进行表征分析。采用四球摩擦磨损试验机评价制备的Ni/β-Ni(OH)2作为润滑油添加剂的摩擦学性能,基础油为PAO6。摩擦试验后,采用SEM分析典型试验钢球磨斑的表面形貌,利用能谱仪(EDS)研究磨斑表面化学元素的组成,探讨Ni/β-Ni(OH)2纳米复合润滑添加剂的减摩抗磨机制。结果表明:Ni/β-Ni(OH)2纳米复合材料作为润滑添加剂具有极好的减摩抗磨性能,显著优于基础油PAO6和未负载纳米Ni的二维β-Ni(OH)2层状材料;与基础油相比,添加0.1%质量分数Ni/β-Ni(OH)2添加剂的油样的摩擦因数和磨斑直径分别降低了17.6%和41.5%;Ni/β-Ni(OH)2纳米复合粉体综合了纳米Ni及层状β-Ni(OH)2两部分结构特性,在摩擦过程中,复合材料中的纳米金属粒子Ni与层状结构材料β-Ni(OH)2能够相互增强起到协同润滑作用。     

Tribological behavior of vegetable oil-based lubricants with nanoparticles of oxides in boundary lubrication conditions

This work studied the development of vegetable based lubricants and the addition of oxides nanoparticles (ZnO and CuO) as additive for extreme pressure (EP), exploring the EP and oil base influence in tribological behavior. The results showed that with the addition of nanoparticles to conventional lubricant, the tribological properties can be significantly improved. A smoother and more compact tribofilm has formed on the worn surface, which is responsible for the further reduced friction and wear. Also, lubricants developed from modified vegetable oil can replace mineral oil, improving the tribological and environmental characteristics. However, the addition of nanoparticles in vegetable base lubricants is not beneficial to wear reduction.     

Tribological evaluation of coconut oil as an environment-friendly lubricant

Increased concerns about environmental damage caused by mineral oil based lubricants, has created a growing worldwide trend of promoting vegetable oil as base oil for automobile lubricants. Coconut oil, which is abundantly available in southern states of India, is reportedly being widely used as two-stroke engine lubricant (2T oil) by autorikshaw¹ drivers. A survey among the users of coconut oil as 2T oil brought forth complaints of increased engine wear. This paper presents tribological properties of coconut oil evaluated using a four-ball tester and a test rig to test the wear on two stroke engines. The influence of an antiwear/extreme pressure (AW/EP) additive on the tribological performance of coconut oil was also evaluated experimentally. The addition of the AW/EP additive has brought about considerable reduction in wear with coconut oil as 2T oil.     

纳米ZnS粒子作为润滑油添加剂摩擦学性能研究

采用均匀沉淀法制备了硬脂酸修饰的纳米ZnS粒子,用四球摩擦磨损试验机考察了其作为润滑油添加剂的摩擦学性能,并用扫描电子显微镜和X射线光电子能谱仪对磨斑进行了表面分析.结果表明:在一定添加量范围内,硬脂酸修饰的纳米ZnS粒子可明显改善基础油的摩擦学性能;在摩擦过程中,纳米ZnS粒子在摩擦表面的沉积和通过摩擦化学反应生成的化学反应膜,显著提高了基础油的抗磨减摩性能.     

Tribological Analysis of a Hydrodynamic Journal Bearing under the Influence of Synthetic and Biolubricants

This study investigated the tribological characteristics of journal bearings exclusively for automotive applications under the influence of a synthetic lubricant (SAE20W40) and chemically modified rapeseed oil (CMRO) as a biolubricant, dispersed with TiO₂, WS₂, and CuO nanoparticles used as antiwear additive. The effects of synthetic and nanobased biolubricants on the tribological behavior of the hydrodynamic journal bearing were examined using a journal bearing test rig by measuring the coefficient of friction, oil film thickness, and wear under a load of 10 kN and a speed of 3,000 rpm. The test results show that CuO nanoadditives that are added to the biolubricant exhibit outstanding wear and friction reduction behavior, better than that with synthetic lubricants as well as other nanobased biolubricants. The inclusion of CuO nanoparticles in the biolubricant decreased the coefficient of friction by 27% and wear by about 47% compared to a synthetic lubricant. Additionally, investigations were performed using atomic force microscopy (AFM) and scanning electron microscopy (SEM) to study the surface morphology and surface roughness behavior of the tested bearing surfaces.     

1,3-丙二胺改性纳米金刚石在润滑油中的摩擦学行为

激光粒度和TEM分析表明,经1,3-丙二胺改性的纳米金刚石的分散性得到显著改善.用MMW-1型立式万能摩擦磨损试验机考察了该改性纳米金刚石作为新型油基极压润滑添加剂的摩擦学行为,结果表明,改性纳米金刚石能明显改善摩擦副的微观磨损状态,显著增强基础油的抗磨性能,基础油中纳米金刚石质量分数为0.6%时,其极压值可提高42%,摩擦因数降低19.0%,磨斑直径降低15.4%,且磨斑较难分辨.     

Tribological properties of AlCoCrFeNiCu high-entropy alloy in hydrogen peroxide solution and in oil lubricant

Pin-on-disc tests to investigate the tribological behavior of AlCoCrFeNiCu high-entropy alloy under lubrication conditions with 90% hydrogen peroxide solution and lubricant oil, respectively, were performed. The study demonstrates that the AlCoCrFeNiCu high-entropy alloy lubricated correspondingly with lubricant of 90% hydrogen peroxide solution (hereafter termed hydrogen peroxide lubricant) and lubricant oil significantly improves its friction and wear-resistance properties. Results showed that the friction coefficient, after a grinding stage, of the rubbing pair was lower than that with normal lubricant oil. The AlCoCrFeNiCu alloy in the lubricant with 90% hydrogen peroxide solution and lubricant oil exhibits a high resistance to wear. Analysis of the worn surface revealed that the AlCoCrFeNiCu high-entropy alloy lubricated with the hydrogen peroxide lubricant exhibited signs of inhomogeneous polishing oxidation and abrasive wear, with the wear mechanism changing with sliding distance, while the rubbing pair in normal lubricant oil is mainly dominated by abrasive wear.     

抗磨添加剂对不同服役阶段润滑油摩擦学性能的影响

采用黏度测试仪测定新油及3种不同服役阶段润滑油的黏度,采用UMT-II摩擦磨损试验机考察其摩擦学性能,并同时考察3种在用润滑油添加抗磨添加剂后的摩擦学性能。研究结果表明:润滑油的黏度随着运行里程数的增加呈现先降后增的趋势;随润滑油运行里程数的增加,润滑油的摩擦因数增大,导致试验钢球的磨损量也增加;抗磨添加剂对不同服役阶段的润滑油的抗磨性能影响程度不同,在磨合磨损期和正常磨损期,加入抗磨添加剂后并不能改善润滑油的抗磨性能,而在异常磨损期,抗磨添加剂的加入可较好地改善润滑油的抗磨性能。     

Tribochemistry and antiwear mechanism of organic–inorganic nanoparticles as lubricant additives

Lubricant-dispersible nanoparticles are prepared via a surface modification synthetic way and characterized by state of the art tools such as TEM. The tribological properties of the nanoparticles as lubricant additives were studied and the results show that the addition of nanoparticles as additives reduced wear and increased load-carrying capacity of base oil remarkably, indicating nanoparticles can be used as anti-wear and extreme-pressure additives with excellent performances. The boundary lubrication mechanism of nanoparticles was discussed that probably an ultra thin film, which is formed by the melting and elongation of nanoparticles under tribological heat and shear force, attributed to good tribological performance of nanoparticulate as additives.     

Ionic liquid modified multi-walled carbon nanotubes as lubricant additive

Multi-walled carbon nanotubes (MWCNTs) were modified by imidazolium-based ionic liquid (IL), 1-hydroxyethyl-3-hexyl imidazolium tetrafluoroborate and used as an additive in base stock IL 1-methyl-3-butylimidazolium tetrafluoroborate as the base lubricant. The effectiveness of using the IL- modified MWCNTs as lubricant additive was evaluated using a ball-on-plate configuration on an Optimol SRV oscillating friction and wear tester. The worn surfaces were examined using scanning electron microscope and the chemical composition on wear tracks was analyzed on an X-ray photoelectron spectrometer. Results suggest excellent anti-wear properties for the IL-modified MWCNTs as lubricant additive.     

金属陶瓷添加剂对船舶主机汽缸套-活塞环摩擦学行为的影响

将普通CD40润滑油作为基础润滑油，在3种不同的载荷作用下，对含有金属陶瓷添加剂润滑油对汽缸套-活塞环摩擦磨损特性的影响进行了模拟试验研究，并与实际使用的普通CD40润滑油的试验结果进行了比较。研究结果表明，汽缸套-活塞环摩擦副在这种添加剂作用下，其磨损失重及摩擦因数都大幅度降低。摩擦副表面扫描电镜分析结果也表明，这种添加剂使摩擦表面更光滑，其本身具有表面自修复作用。     

分散剂对有机粘土润滑油摩擦学性能的影响

以30#机械油为基础油,以0.4%季铵盐修饰有机粘土为添加剂,5%低碱值合成磺酸钙和5%聚异丁烯双丁二酰亚胺为分散剂,制备了几种分散剂优化的有机粘土润滑油。采用OPTIEN2120型紫外/可见分光光度计对分散剂的分散效果进行了检测;在M-200和MS-800型摩擦磨损试验机上,分别对不同分散剂作用下的有机粘土润滑油的减摩抗磨性能和承载能力进行了测试。分散效果检测表明分散剂可有效控制粘土微粒的粒径,阻止粘土微粒的团聚,使得粘土微粒在基础油中有良好的分散稳定性。摩擦磨损试验表明:分散剂能改进有机粘土润滑油的摩擦学性能,其中2.5%低碱值合成磺酸钙与2.5%聚异丁烯双丁二酰亚胺分散剂复配使用时有机粘土润滑油的摩擦学性能最佳;分散剂的加入在一定程度上能够提高有机粘土润滑油的承载能力。     

基于油液分析的汽车发动机摩擦系统故障诊断专家系统知识库的建立

采集汽车发动机润滑系统中摩擦副经历磨擦学行为的信息是诊断发动机摩擦系统故障的有效手段。油液分析从摩擦学系统的润滑剂和磨损物两方面获得磨擦副的润滑和磨损状态的信息。但常规的油液分析信息处理方法上的不足影响了油液分析技术在汽车行业的实际应用,开发基于油液分析的故障诊断系统,无疑会改善油液分析的诊断准确性和诊断成本。本文着重针对该诊断专家系统知识库的建立,     

N-酰基谷氨酸在矿物油中的摩擦学性能研究

分别在油酸和月桂酸分子中引入氮,合成了2种新型的含氮润滑油添加剂——N-油酰基谷氨酸和N-月桂酰基谷氨酸。利用四球摩擦磨损试验机考察了2种添加剂作为HVI350矿物基础油极压抗磨添加剂时的摩擦学性能,通过测定不同条件下的最大无卡咬负荷和磨斑直径及摩擦因数,分析和研究了载荷、摩擦时间、添加剂含量对矿物油最大无卡咬负荷和磨斑直径及摩擦因数的影响。试验结果表明:2种添加剂均可以明显提高基础油的承载能力和抗磨减摩性能,添加剂N-油酰基谷氨酸在矿物油中的承载能力明显优于N-月桂酰基谷氨酸,而N-月桂酰基谷氨酸对提高矿物基础油抗磨减摩性能的效果好于添加剂N-油酰基谷氨酸。试验还表明添加剂的含量并非越高越好,否则磨斑直径将增大。     

Tribological properties of diamond and SiO2 nanoparticles added in paraffin

This work studies the tribological properties of liquid paraffin to which diamond and SiO₂ nanoparticles, which were prepared by the surface modification method using oleic acid, had been added and observed by scanning electron microscopy (SEM) and infrared (IR) spectroscopy. Also, the dispersion capability and stability dispersivity of both modified nanoparticles in liquid paraffin were measured using a spectrophotometer. The measurements show the dispersion capacity and the dispersing stability of oleic acid-modified diamond and SiO₂ nanoparticles in liquid paraffin.The tribological properties are evaluated using a ball-on-ring wear tester. The results show that both nanoparticles as additives in liquid paraffin at a tiny concentration have better antiwear and antifriction properties than the pure paraffin oil. Also, SEM was used to observe the plowing of nanoscale grooves of worn surfaces by diamond and SiO₂ nanoparticles.