表面修饰纳米铜颗粒添加剂的摩擦学性能

采用液相还原两步法制备了表面修饰的铜纳米颗粒,采用美国产UMT-3摩擦试验机进行四球长时抗磨实验,考察了其作为150N基础油添加剂的抗磨减摩性能及对钢球磨损表面的修复作用,用SEM和EDS分析了磨损表面的形貌和元素组成.结果表明,经过表面修饰的纳米铜颗粒作为添加剂能显著改善150N基础油的抗磨减摩性能.含4%纳米铜颗粒...     

纳米WS_2润滑油添加剂在直流磁场下的摩擦磨损特性

在四球摩擦磨损实验机摩擦区域添加了直流磁场发生装置,研究了添加经修饰的纳米WS_2润滑油在直流磁场作用下的摩擦磨损性能,用扫描电镜(SEM)配合能谱仪(EDS)及X射线光电子能谱仪(XPS)对钢球磨斑区域表面形貌和典型元素的含量及化学状态进行了分析,并探讨了相关的摩擦学机理。实验结果表明:经修饰后的纳米WS_2在150SN基础油中稳定性良好,含纳米WS_2的润滑油体现出更好的润滑性能,在纳米WS_2含量相同时,直流磁场下的润滑油抗磨减摩效果更好。直流磁场对纳米WS_2有一定的聚集效应,并会提高摩擦化学反应发生的概率。     

纳米WS2润滑油添加剂在直流磁场下的摩擦磨损特性

在四球摩擦磨损实验机摩擦区域添加了直流磁场发生装置，研究了添加经修饰的纳米WS₂润滑油在直流磁场作用下的摩擦磨损性能，用扫描电镜（SEM）配合能谱仪（EDS）及X射线光电子能谱仪（XPS）对钢球磨斑区域表面形貌和典型元素的含量及化学状态进行了分析，并探讨了相关的摩擦学机理。实验结果表明：经修饰后的纳米WS₂在150SN基础油中稳定性良好，含纳米WS₂的润滑油体现出更好的润滑性能，在纳米WS₂含量相同时，直流磁场下的润滑油抗磨减摩效果更好。直流磁场对纳米WS₂有一定的聚集效应，并会提高摩擦化学反应发生的概率。     

蛇纹石微粉对球墨铸铁摩擦副的减摩抗磨作用机理

采用MM-200摩擦磨损试验机评价了蛇纹石微粉作为润滑油添加剂对球墨铸铁的减摩抗磨作用.借助扫描电子显微镜、X射线能谱仪、纳米压痕仪、X射线光电子能谱仪等对磨损表面进行了分析,并探讨了其减摩抗磨机理.结果表明:蛇纹石微粉能显著提高球墨铸铁摩擦副的摩擦学性能.当添加量为0.5%(质量分数)时,能使摩擦系数较基础油降低51.5%,磨损量减少29.6%.磨损表面元素主要由Mg,Si,Fe,O,C组成,磨损表面光滑平整且具有较高的纳米力学性能.分析认为:由于蛇纹石微粉呈层片状结构,且表面存在大量的不饱和键而具有很高的化学活性,在摩擦力作用下趋向与摩擦表面发生物理、化学作用,形成铁镁的氧化物、水合氧化物、硅酸盐,铁的碳化物及石墨化碳等物相,可强化摩擦副表面,增强其自润滑能力,提高其减摩抗磨性能.     

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。     

纳米高岭土作为润滑添加剂的减摩行为

将经油酸改性的纳米高岭土用作润滑添加剂,利用四球摩擦试验机研究了其在#40机油中的减摩行为。利用扫描电子显微镜、X射线光电子能谱仪、Fourier变换红外光谱仪、Raman光谱仪、比表面积测定仪和热重分析仪等手段对摩擦接触面和摩擦前后纳米颗粒的性质进行表征。结果表明:润滑油中的纳米颗粒粘附在摩擦接触面上,并与摩擦副发生摩擦化学反应,最终在摩擦接触面上生成富含Si、Al、Fe、O和C等元素化合物的自修复保护膜,阻止摩擦副间直接接触,从而降低摩擦、减少磨损;尤其当纳米颗粒在基础油中的质量分数为1.0%时,摩擦副的平均摩擦系数和磨斑直径最小,与纯基础油时相比,分别降低了约23%和16%,且表面更为平整、犁沟更浅。与摩擦前相比,摩擦后的纳米高岭土性质(如颗粒尺寸、晶体结构等)也有所变化。另外,讨论了在润滑油中纳米高岭土的减摩原理。     

水润滑下偶件表面粗糙度对碳纤维增强PEEK复合材料摩擦学性能的影响

以聚醚醚酮(PEEK)复合材料为销样,316不锈钢材料为盘样,在销-盘摩擦磨损试验机上考察了水润滑条件下偶件表面粗糙度对纯PEEK及碳纤维增强PEEK复合材料摩擦学性能的影响,并用光学显微镜观察了PEEK复合材料的磨损表面形貌。结果表明,在水润滑条件下,碳纤维增强PEEK复合材料的耐磨性能明显提高,磨损率比纯PEEK的磨损率降低了4~6倍。当偶件表面粗糙度R_a处于0.08~0.09μm范围内时,PEEK复合材料可以取得较低的磨损率;当偶件表面粗糙度R_a的值过高或者过低时,摩擦磨损机理将发生改变。     

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。     

黑云母/氯化镧复合粉体的摩擦性能

以黑云母粗矿和氯化镧为原料,通过行星式球磨机制备氯化镧/黑云母复合粉体润滑添加剂,在500SN基础油中添加1%(质量分数)的氯化镧/黑云母复合粉体润滑添加剂制成新型润滑油,并在SFT-2M销盘式摩擦磨损试验机上对轴承钢试件的摩擦副进行基础油与新型润滑油的对比试验及其摩擦学性能评价。结果表明:新型润滑油具有更好的减摩耐磨性,其摩擦因数较基础油降低约20%,磨损后的试件表面光滑,复合润滑添加剂在摩擦副间发生复杂的物理化学反应,在表面形成了非均匀覆盖的摩擦表面膜。     

聚四氟乙烯基耐磨涂层的摩擦学性能研究

通过喷涂的方法将聚四氟乙烯基耐磨涂料喷涂在摩擦试验样件基体表面,将该摩擦试验样件及其配对的摩擦副进行摩擦磨损试验、表面形貌分析和改变喷枪压力及表面粗糙度的工艺参数以分析涂层性能。结果表明:聚四氟乙烯基耐磨涂层经摩擦系数、磨损量测试后,摩擦系数先增大再稳定不变,最后稳定在0.15;磨损量先增大再减小最后稳定,即磨损量最后为恒定值。从表面形貌分析得出摩擦副的磨损主要是磨料磨损造成的。当喷枪压力为0.3 MPa时,耐磨涂层的膜层均匀性最佳;表面粗糙度为6.3μm时,耐磨涂层与基体的附着效果较好。其结论得出该涂层摩擦系数和磨损量较低,耐磨性能较好,同时,当喷枪压力和表面粗糙度工艺参数合适时,耐磨涂层的性能效果最佳。     

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.     

表面处理Al2O3增强PTFE基复合材料的摩擦学性能

利用MM-200型摩擦磨损试验机考察了表面处理与未处理纳米Al2O3对填充聚四氟乙烯(PTFE)复合材料摩擦学性能的影响，采用扫描电子显微镜观察试样混合效果和磨损表面形貌并分析其磨损机理。结果表明：填充PTFE摩擦系数比PTFE略有增加。纳米Al2O3可以提高PTFE耐磨性，表面处理纳米Al2O3在PTFE中能较均匀分散，其耐磨性比相同含量但未经表面处理的纳米Al2O3填充PTFE高一倍。导致PTFE磨损的重要机理是切削和粘着磨损。     

Tribological properties of bismaleimide composites with surface‐modified SiO2 nanoparticles

In this article, the surface of SiO₂ nanoparticles was modified by silane coupling agent N‐(2‐aminoethyl)‐γ‐aminopropylmethyl dimethoxy silane. The bismaleimide nanocomposites with surface‐modified SiO₂ nanoparticles or unmodified SiO₂ nanoparticles were prepared by the same casting method. The tribological performance of the nanocomposites was studied on an M‐200 friction and wear tester. The results indicated that the addition of SiO₂ nanoparticles could decrease the frictional coefficient and the wear rate of the composites. The nanocomposites with surface‐modified SiO₂ nanoparticles showed better wear resistance and lower frictional coefficient than that with the unmodified nanoparticles SiO₂. The specific wear rate and the steady frictional coefficient of the composite with 1.0 wt % surface‐modified SiO₂ nanoparticles are only 1.8 × 10^?6 mm³/N m and 0.21, respectively. The dispersion of surface‐modified SiO₂ nanoparticles in resin matrix was observed with transmission electron microscope, and the worn surfaces of pure resin matrix and the nanocomposites were observed with scanning electron microscope. The different tribological behavior of the resin matrix and the filled composites should be dependent on their different mechanical properties and wear mechanism. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of surface roughness and reciprocating time on the tribological properties of the polyimide composites

Novel polyimide (PI) composites were designed and prepared as a frictional material for ultrasonic motors (USM). The effect of roughness and reciprocating time on the tribological properties of PI composites was specially investigated for simulating USM operating condition. These typical PI composites were designed along with the special characteristics of USM by filling proportional solid lubricants and nanoparticles, and prepared using classical hot‐press sintering. The friction and wear behavior of PI composites with different surface roughness polished by SiC sandpaper and various reciprocating time was carried out on a pin‐on‐plate tribo‐meter against GCr15 steel pin. The worn surface was observed by SEM to reveal wear mechanisms. Experimental results indicated that the coefficient of friction and specific wear rate increased with an increase of surface roughness which was detrimental for USM to prolong the service life. The coefficient of friction and wear volume will increase with an increase of reciprocating time due to fatigue wear, but specific wear rate will decrease with the minimum value of 2.1 × 10^?6 mm³/N m. This study can provide significant guidance for USM to optimize frictional surface and running‐in time. POLYM. ENG. SCI., 59:483–489, 2019. © 2018 Society of Plastics Engineers     

纳米颗粒增强摩擦材料摩擦学性能研究

以丁腈橡胶改性酚醛树脂为基体,芳纶纤维、玻璃纤维为增强纤维,选用不同类型的纳米颗粒作为填料设计摩擦材料组分配比,并通过热压烧结制备摩擦材料。通过摩擦磨损试验机测试其在干摩擦条件下的摩擦学性能,并用扫描电镜(SEM)对材料的磨损形貌进行观察分析,以研究不同类型的纳米颗粒对摩擦材料性能的影响。研究表明:在干摩擦条件下,经过纳米颗粒改性的摩擦材料摩擦系数、硬度比未改性的材料有不同程度的提高,同时磨损率有很大程度的降低;纳米颗粒改性的摩擦材料摩擦系数、磨损率变化趋势具有一致性,均随着实验载荷、滑动速度的增大而逐渐减小;纳米颗粒改性后的摩擦材料磨损机理表现为疲劳磨损与磨粒磨损并存,而未改性的材料磨损机理主要表现为疲劳磨损。     

Friction behaviour and wear resistance of diamond-like carbon films under cryogenic temperatures

A study has been made of the friction behaviour and wear resistance in liquid nitrogen medium of pin-and-disc pairs with diamond-like carbon (DLC) coatings deposited onto disc surfaces of varying initial roughness, and in a number of cases onto pin surfaces. The dependence of the coefficient of friction on initial roughness has been shown to be extreme. Peculiarities of microrelief formation at the contact surface and the composition of the wear debris for the DLC-coated mating pairs were observed. Possible mechanisms of friction interaction for diamond-like coatings at cryogenic temperatures are considered.     

Mechanical and tribological properties of polyoxymethylene modified with nanoparticles and solid lubricants

Polyoxymethylene (POM) composites modified with nanoparticles, polytetrafluoroethylene (PTFE) and MoS₂ were prepared by a twin‐screw extruder. The effect of nanoparticles and solid lubricant PTFE/MoS₂ on mechanical and tribological properties of the composites were studied. Tribological tests were conducted on an Amsler friction and wear tester using a block‐on‐ring arrangement under dry sliding and oil lubricated conditions, respectively. The results showed that generally speaking POM nanocomposites had better stiffness and tribological properties than corresponding POM composites attributed to the high surface energy of nanoparticles, except that the tensile strength of three composites and dry‐sliding tribological properties of POM/3%Al₂O₃ nanocomposite decreased due to the agglomeration of nanoparticles. Tribological properties differed under dry sliding and oil lubricated conditions. The friction coefficient and wear volume of POM nanocomposites under oil lubricated condition decreased significantly. The increased deformation resistance supported the increased wear resistance of POM nanocomposites. POM/PTFE/MoS₂/3%Al₂O₃ nanocomposite had the best mechanical and tribological properties of all three composites, which was attributed to the synergistic effect of nanoparticles and PTFE/MoS₂. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

硫化铜纳米颗粒的原位合成及摩擦学性能

采用原位合成的方法合成了硫化铜纳米微粒,通过静置及高低速离心测试,证明硫化铜纳米微粒在基础油石蜡中具有良好的分散稳定性。TEM研究证明合成的纳米颗粒粒径约为20 nm。通过FT-IR表征合成样品,发现油酸分子-COOH部分和硫化铜表面发生了化学性吸附,增强了硫化铜纳米微粒在基础油中的油溶性。用高速环-块磨损机考察了含硫化铜颗粒的基础油的摩擦学性能,发现添加有油酸修饰的硫化铜纳米颗粒有显著的抗磨减摩效果。     

纳米SiO2／双马来酰亚胺复合材料的性能研究

采用浇铸成型法制备了纳米SiO2粒子填充双马来酰亚胺(BMI-BA)复合材料，研究了纳米SiO2的填充量对复合材料滑动磨损性能的影响。在磨损机上测试该复合材料的摩擦和磨损性能，利用扫描电镜(SEM)观察了复合材料的磨损表面和对磨环的表面形貌。结果表明，纳米SiO2能够有效地提高复合材料的力学性能和摩擦学性能。当纳米SiO2粒子的添加量为0．75％(质量含量，下同)时，复合材料的综合力学性能最好；当纳米SiO2粒子的的添加量为1．0％时，复合材料的耐磨性能最好。SEM显示复合材料主要是黏着磨损，能在对磨环上形成薄而连续的均匀转移膜，而BMI-BA树脂主要发生的是疲劳磨损，并伴有塑性变形。     

Wear of Biopolymers under Reciprocating Sliding Conditions against Different Counterfaces

The objective of this study was to investigate the wear resistance of ultrahigh‐molecular weight polyethylene (UHMWPE) and crosslinked polyethylene (XLPE) against different counterfaces. Friction and wear studies were evaluated under dry reciprocating sliding conditions at room temperature. Ti6Al4V discs finished in polished, lapped, and ground conditions were reciprocated against polymer cylinders. In addition, abrasive wear studies were conducted using different abrasive grit sizes. The friction and wear properties of the two polyethylenes were strongly affected by the different counterfaces. XLPE showed important friction and wear sensitivity with the change of surface roughness of the Ti6Al4V disc, as well as with the change in abrasive grit size. Scanning electron microscopy and energy‐dispersive X‐ray (EDX) analysis of the worn disc surfaces and the polymer pins indicated the wear mechanisms affecting the polyethylenes. POLYM. ENG. SCI., 59:2356–2366, 2019. © 2019 Society of Plastics Engineers