坡缕石/有机钼复合润滑油添加剂摩擦性能

将配比不同的纳米坡缕石/有机钼复合添加剂添加至润滑油中,用超声波分散仪使其均匀分散,制备出不同的润滑油试样。对试样进行四球机摩擦试验,以便探究纳米坡缕石/有机钼不同添加量对润滑油性能的影响。结果表明,纳米坡缕石/有机钼复合添加剂能够有效的提高润滑油的摩擦学性能:在添加剂质量分数为3%,而其中坡缕石/有机钼的比值约为2∶1时,润滑油的减摩抗磨性最好。坡缕石/有机钼复合添加剂比单一有机钼、坡缕石润滑油添加剂摩擦学性能更优越。     

纳米粒子作为润滑添加剂的性能研究

由于我国所需润滑产品的剧增以及人们环保意识的增强,传统润滑添加剂已不能满足现代工业发展的需要.对纳米润滑添加剂的摩擦学性能、经济性能以及环境危害性等方面进行了综合的分析,分析表明:加入了纳米添加剂的润滑油具有优异的摩擦学性能、良好的经济性能以及好的环境友好性.     

减摩抗磨类新型润滑油添加剂的研究进展

减摩抗磨类润滑油添加剂能提高基础润滑油的摩擦学性能使其在润滑领域具有广阔的应用前景,但是商用润滑油添加剂大多含有P、S等有害元素,因此,寻找更加环保、经济的润滑油添加剂具有重要意义。本文根据润滑油添加剂结构种类和润滑机理的不同,以及国内外各种润滑油添加剂在润滑方面的相关成果,综述了近年来纳米颗粒(纳米单质及其复合颗粒、纳米氧化物、纳米硫化物、纳米氮化物)、含氮杂环化合物及其衍生物、硼酸酯及其衍生物、离子液体等添加剂的合成方法以及在减摩抗磨方面的应用,并对其发展状况和减摩抗磨机理进行了探究。指出了其润滑机理主要为吸附膜机理、摩擦反应膜机理和滚珠机理。最后对其存在的问题进行分析,提出了当前润滑领域研究的热点和方向依然是复合添加剂的制备和机理探究。     

纳米粒子添加剂在润滑剂中的应用与开发

具有特殊的物理、化学性质的纳米粒子在摩擦学领域引起人们极大的兴趣,研究表明,纳米粒子添加剂具有优良的抗磨减摩性能。但目前含纳米粒子润滑剂的商业产品寥寥无几,这主要是由于纳米粒子在润滑剂中的分散性和稳定性问题还没得到很好解决,本文详细综述了纳米粒子在润滑油中的分散性及稳定性的研究现状,纳米粒子作为油品添加剂的应用与开发等问题。     

蒙脱土和硼酸镧复合纳米润滑油添加剂的摩擦学性能研究

将KH550偶联剂修饰的纳米蒙脱土和KH550偶联剂修饰的纳米硼酸镧,按不同质量分数的纳米蒙脱土与相同质量分数的纳米硼酸镧复合物和单一不同质量分数的纳米蒙脱土分别加入到150N基础油中,制备质量分数0%～4%的5种纳米蒙脱土与纳米硼酸镧复合添加剂的润滑油和质量分数0%～4%的5种单一纳米蒙脱土添加剂润滑油体系,在四球摩擦实验机上考察了纳米蒙脱土和纳米硼酸镧复合润滑油添加剂的摩擦学性能。实验结果表明:当其添加2%的纳米蒙脱土和2%的纳米硼酸镧的复合物具有良好的抗磨减磨性能。     

复合纳米润滑油添加剂抗磨减摩性及自修复性

将复合纳米微粒分散到基础油中,使用布鲁克摩擦磨损试验机和电子显微镜研究复合纳米添加剂的摩擦学性能和自修复性能。利用电子显微镜和三维轮廓仪观察试板的表面磨痕形貌,利用电子天平对试板的自修复前后的质量进行对比,及利用表面粗糙度仪测量试板表面粗糙度的改变。结果表明,复合纳米添加剂可以明显改善润滑油的摩擦学性能,具有优良的自修复性能。     

纳米铟润滑油添加剂的摩擦学性能研究

将KH550偶联剂修饰的纳米铟按不同质量分数加入150 N基础油中,在四球摩擦实验机上考察了改性纳米铟作为润滑油添加剂的摩擦学性能,并通过SEM检测结果分析摩擦磨损机制。实验结果表明:当其添加量约为0.8%左右时改性纳米铟具有良好的减摩抗磨性能。     

纳米材料作为润滑油添加剂的应用前景

介绍了各类纳米材料作为润滑油添加剂的优势和各类纳米材料的摩擦学性能.总结了纳米材料的减摩作用机理.归纳了纳米材料作为润滑油添加剂的发展趋势.     

噻二唑衍生物润滑油添加剂研究进展

综述了近年来噻二唑衍生物润滑油添加剂的研究进展。主要介绍了含黄原酸结构的噻二唑衍生物添加剂、含二硫键结构的噻二唑衍生物添加剂、硼酸酯(盐)类噻二唑衍生物添加剂、含酰胺结构的噻二唑衍生物添加剂、噻二唑希夫碱添加剂、含酯或醚结构的噻二唑衍生物添加剂等一系列单一噻二唑润滑油添加剂。此外,还介绍了纳米颗粒与噻二唑衍生物的复合润滑油添加剂,该类复合润滑油添加剂能够显著提高润滑油基础油的摩擦性能。提出了制备油酸型噻二唑衍生物润滑油添加剂、噻二唑类离子液体润滑油添加剂及噻二唑纳米微粒润滑油添加剂的展望。     

发动机用润滑油添加剂的研究进展

综述了近年来国内外发动机用润滑油添加剂的种类,包括球形微纳米颗粒润滑油添加剂、硼酸酯润滑油添加剂、金属钼/钨系列润滑油添加剂与苯三唑脂肪胺盐润滑油添加剂等。主要从润滑机理、制备方法及应用进行综述,指出了这些润滑油添加剂的研究现状及优缺点,并展望了润滑油添加剂的发展前景。     

Tribological properties of Al2O3 nanoparticles as lubricating oil additives

Nano-scale Al₂O₃ spherical particles, prepared via a hydrothermal method and modified by silane coupling agent, can be well-dispersed in lubricating oil. The tribology properties of Al₂O₃ nanoparticles as lubricating oil additives have been studied by four-ball and thrust-ring friction test, which illustrate that the modified Al₂O₃ nanoparticles can effectively improve the lubricating behaviors compared to the base oil. When the added concentration is 0.1 wt%, the friction coefficient and the wear scar diameter are both smallest. The lubrication mechanism is that a self-laminating protective film is formed on the friction surface and the wear behavior changes from sliding friction to rolling friction.     

机械密封端面磨损的失效评述及其研究方向

对机械密封磨损失效的原因进行了归纳和分析，指出机械密封端面间的润滑状态与密封系统和工作条件有关；同时指出了机械密封摩擦学方面的研究方向。     

Construction and tribological properties of poly acrylic acid-poly(3-(methacryloylamino)propyl) dimethyl(3-sulfopropyl)ammonium hydroxide hydrogel coatings embedded with SiO2 nanoparticles on Ti6Al4V substrate

The development of highly effective bio-lubricant coatings for arthritis treatment is extremely demanded. Herein, inspired by the efficient lubrication of articular cartilage, acrylic acid (AA) with (3-(methacryloylamino) propyl) dimethyl (3-sulfopropyl) ammonium hydroxide (MPDSAH) hydrogel coatings containing nanoparticles on Ti6Al4V substrate were designed and fabricated via UV grafting technology. SiO₂ and SiO₂ grafted with PAA polymer brushes (SiO₂-g-PAA) were separately doped into the PAA-PMPDSAH hydrogel. The PAA-PMPDSAH/SiO₂-g-PAA exhibits good tensile and compressive properties compared with PAA-PMPDSAH/SiO₂ hydrogel, with an enhancement of 183.4% in tensile modulus and 60.8% in compressive modulus. The PAA-PMPDSAH/SiO₂-g-PAA hydrogel coatings exhibit a low wear volume, 2.9 ± 0.16 × 10⁶ μm³, representing a decline of 32.1% and 61.3% compared with the PAA-PMPDSAH and PAA-PMPDSAH/SiO₂ hydrogel coatings, respectively. The antiwear performance has obviously improved. The hydrophilic PAA polymer brushes prevent the agglomeration of nanoparticles and promote homogeneously dispersion within the hydrogel. The three-dimensional crosslinked network structure of hydrogel effectively protects the structural integrity of the polymer brushes, thereby facilitating enduring lubrication properties. This work provides a strategy for promising artificial joint lubrication in biomedical fields.     

The molecular dynamic simulation on impact and friction characters of nanofluids with many nanoparticles system

Impact and friction model of nanofluid for molecular dynamics simulation was built which consists of two Cu plates and Cu-Ar nanofluid. The Cu-Ar nanofluid model consisted of eight spherical copper nanoparticles with each particle diameter of 4 nm and argon atoms as base liquid. The Lennard-Jones potential function was adopted to deal with the interactions between atoms. Thus motion states and interaction of nanoparticles at different time through impact and friction process could be obtained and friction mechanism of nanofluids could be analyzed. In the friction process, nanoparticles showed motions of rotation and translation, but effected by the interactions of nanoparticles, the rotation of nanoparticles was trapped during the compression process. In this process, agglomeration of nanoparticles was very apparent, with the pressure increasing, the phenomenon became more prominent. The reunited nanoparticles would provide supporting efforts for the whole channel, and in the meantime reduced the contact between two friction surfaces, therefore, strengthened lubrication and decreased friction. In the condition of overlarge positive pressure, the nanoparticles would be crashed and formed particles on atomic level and strayed in base liquid.     

Highly-dispersible boron nitride nanoparticles by spray drying and pyrolysis

A spray drying and pyrolysis synthesis route was developed and it successfully prepared boron nitride (BN) nanoparticles with high dispersivity. During the experiment, the extremely rapid drying of the boric acid/urea solution during the spray-drying process resulted in the formation of homogeneous precursors, which was the key for the final pyrolysis synthesis of BN nanoparticles with high dispersibility and uniform diameters (~20 nm). Compared with boron nitride synthesized without using spray drying, the as-prepared BN nanoparticles possess higher specific surface area (145.01 m² g⁻¹) and larger pore volume (0.41 cm³ g⁻¹). Especially, we used the BN nanoparticles as lubricant and incorporated it into the liquid paraffin (LP). The experiment results show that the LP presents outstanding antifriction properties for a BN content of 1.5 wt%. These results suggest that the h-BN nanoparticles have significant potential applications in the field of tribology.     

Gaps between Theory and Practice of Adhesion

Diagnosis of many future adhesion problems will be based on current knowledge, reported at this symposium. But, prognosis permitting a decisive choice of materials and of methods in a specific situation, is not always possible. Considering the broad range of disciplines involved, a systems approach is proposed to reach a logical overlap between theory and practice. Four systems will be discussed in some detail.

The established concepts of adhesive strength in mechanical systems should be amended by a consideration of fracture energies in terms of a macroscopic, continuum model, followed by a discussion of microscopic and molecular structures. Interface systems are common to both adhesion science and tribology. Recent work on the nature of static friction and of boundary lubrication has contributed to the understanding of interface adhesion. Among the operational variables evaluated in production systems the 'adhesionable' properties of adherends are badly in need of closer examination. In biological systems the strength and toughness of calciferous tissues should be compared with the corresponding properties of interlocking adhesives.     

Temperature effect on mechanical strength and frictional properties of polytetrafluoroethylene-based core-shell nanocomposites

Polytetrafluoroethylene (PTFE) has shown an outstanding lubricity as a solid lubricant, but its application is limited due to its low-mechanical strength and high-wear rate. In this study, core-shell nanoparticles were synthesized using PTFE as the core and polymethylmethacrylate (PMMA) as the shell. The formed core-shell nanocomposites by leveraging the core-shell nanoparticles as basic structural units exhibit remarkable enhancement on uniformity, tensile strength, and wear resistance, compared to mechanically mixed composites with the same composition. Our experiments demonstrated the following results: (1) Owing to the excellent uniformity, the maximum tensile strength of core-shell nanocomposites was 62 MPa, three times higher than that of mechanically mixed composites. (2) The composite matrix formed by PMMA shell had better reinforcement and protection effect on inner PTFE phase, resulting in a reduced wear rate of 0.3 × 10⁻⁵ mm³/(N m), one order of magnitude lower than that of mechanically mixed composites. (3) The friction coefficient and interfacial mechanical properties of the core-shell nanocomposites at different temperatures have been systematically studied to get insights into lubrication mechanisms. It is proved that the temperature can decrease the modulus and increase the interfacial adhesion as well as the loss tangent of the core-shell nanocomposites, thus affecting the lubrication properties in multiple ways.     

Biodiesel influence on tribology characteristics of a diesel engine

This paper deals with the influence of biodiesel on some tribology characteristics of a bus diesel engine with a mechanically controlled fuel injection system. The tests have been performed on a fully equipped engine test bed, on a fuel injection test bed and on a discharge coefficient testing device. The tested fuel was neat biodiesel produced from rapeseed. Attention was focused on the biodiesel influence on the pump plunger surface roughness, on the carbon deposits in the combustion chamber, on the injector and in the injector nozzle hole. The pump plunger surface was analyzed by experimentally determined roughness parameters and by a microscope. The carbon deposits at fuel injector and in the combustion chamber were examined using endoscopic inspection. The deposits in the injector nozzle were investigated indirectly by measuring the nozzle discharge coefficient. Numerical simulation has been performed in order to estimate the influence of the discharge coefficient variation on the computed injection characteristics. The obtained results indicate that biodiesel usage may even improve the pump plunger lubrication conditions. Furthermore, the carbon deposits in the combustion chambers did not vary significantly in quantity but they were noticeably redistributed. Finally, it was found out that the variation of the nozzle discharge coefficient has to be taken into account only if high accuracy of numerical simulation is desired.