白云母 / CeO2 复合粉体的制备及其摩擦学性能研究

目的研究白云母/CeO2复合粉体在500SN基础油中的抗磨减摩性能和抗磨减摩机理。方法以白云母、硝酸铈、草酸为原料,通过球磨固相法制备不同配比的白云母/CeO2复合粉体,用油酸改性,采用XRD,SEM等对粉体的结构特征和表面形貌进行表征,并通过四球磨损实验考察不同油样的摩擦学性能。结果添加了白云母/CeO2和单一白云母的润滑油,摩擦学性能均比无添加的基础油优越。其中,添加了白云母/10%CeO2复合粉体的润滑油抗磨减摩性能最好,摩擦系数比基础油降低了10.7%,磨斑直径比基础油减少了24.4%。结论白云母/CeO2复合粉体有较好的抗磨减摩能力,对磨损表面有修复作用,合理配比的白云母/CeO2能有效提高基础油的抗磨减摩性能。     

铜纳米添加剂的制备及其摩擦学性能分析

采用KBH4液相还原法制备了纳米铜颗粒,通过X射线衍射和透射电镜分析,得出所制备的纳米铜颗粒的粒径约为20nm的圆球形颗粒。分析了表面修饰的纳米铜颗粒作为润滑油添加剂的摩擦学性能和作用机理,结果表明纳米铜的加入,能在磨损表面形成一层润滑性的铜膜,从而能够有效地改善润滑油的抗磨减摩性能,降低润滑油的摩擦因数,减小摩擦副的磨损量,并得出纳米铜添加剂的最佳用量。     

The effect of submicron-sized initial tungsten powders on microstructure and properties of infiltrated W-25 wt.% Cu alloys

In the present work, several W-25 wt% Cu alloys have been prepared through combined processes of high-energy ball-milling, liquid-phase sintering and infiltration, using the precursors of industrial copper powders with an average particle size of 50 μm and tungsten powders with alternative average particle size of 8 μm, 800 nm, 600 nm or 400 nm. Microstructure characteristics, relative density, hardness and electrical conductivity of the WCu alloys were investigated to elucidate the effect of initial particle size of tungsten powders. EBSD was further utilized to reveal the orientation and grain size distribution in the WCu alloys prepared by 8 μm and 400 nm-sized tungsten powders. The results showed that the WCu alloy made by 400 nm-sized tungsten powders exhibited excellent homogeneity for both sintered tungsten powders and grains, together with the highest relative density of 98.9%, the highest hardness of 230 HB, and good electrical conductivity of 48.7% IACS. Moreover, it also showed highly improved arc erosion and mechanical wear resistances.     

镧化合物对煤间接液化柴油碳烟颗粒摩擦学特性的影响

目的 研究镧化合物对含煤间接液化柴油碳烟润滑油摩擦磨损性能的影响.方法 利用四球长时摩擦磨损试验机,分别考察不同浓度氟化镧(LaF3)和氧化镧(La2O3)对含煤间接液化柴油碳烟(Fischer-Tropsch synthesis diesel soot,F-T DS)与0#柴油碳烟(Diesel soot,DS)白油的润滑性能的影响,利用多功能万能工具显微镜、扫描电镜与能谱、X射线光电子能谱等仪器对磨斑直径、结构、形貌、组成及元素价态进行表征.结果 在含F-T DS白油体系中,添加0.4％(质量分数)镧化合物LaF3或La2O3时,减摩抗磨效果最优,平均摩擦系数(AFC)分别为0.070、0.058,较未添加时(0.094)分别下降25.5％和38.3％,平均磨斑直径(AWSD)分别为0.4318、0.4207 mm,较未添加时减少了33.6％和35.2％.在含DS白油体系中,添加0.6％ 镧化合物LaF3或La2O3时,减摩效果最佳,AFC分别下降11％和16％;添加0.8％ 镧化合物时,抗磨效果最优,AWSD降幅分别为24.8％和33.7％,La2O3抗磨效果优于LaF3.结论 添加少量镧化合物可以改善含F-T DS与DS白油的减摩抗磨效果.其减摩抗磨机理可能是,通过形成转移膜,或在摩擦进程中添加剂吸附在接触表面形成镧系边界润滑保护膜,改善了润滑状态,起到了减摩抗磨作用.     

钛合金切削用磷酸酯类添加剂润滑特性及有机碱复配研究

目的 提高水基润滑液对钛合金的润滑抗磨性能。方法 针对钛合金/硬质合金摩擦副,使用SRV往复式球盘摩擦磨损实验机,测试了常用的三种切削液及四种水溶性磷酸酯溶液的摩擦磨损效果。通过三维白光干涉形貌仪与扫描电子显微镜对磨损表面形貌及磨痕内外能谱进行检测,分析磨损机理及润滑性能,探究对钛合金具有高效润滑作用的水溶性添加剂,并通过有机碱调节溶液的pH,复配适用于钛合金的润滑体系。结果 对铝合金具有很好润滑作用的切削油对钛合金润滑效果很差,而所选水基润滑液效果较好。研究发现,四种水溶性磷酸酯溶液在质量分数为2%时即可对钛合金产生较好的润滑效果,其中,脂肪醇醚磷酸酯（MOA-3P）润滑效果最突出,摩擦系数最低（0.15）,且稳定、粘着磨损最少。通过二甘醇胺及三乙醇胺调节磷酸酯溶液pH至碱性,除支链烷基化磷酸酯（CP-NF-3）溶液外,其他溶液的摩擦系数均有所变大,且波动性增强,而CP-NF-3磷酸酯碱性溶液润滑时,摩擦系数变化很小,稳定在0.2左右。结论 水溶性磷酸酯与适当的有机碱复配的润滑液,可实现对钛合金的良好润滑,用于钛合金水基切削液体系的研发。     

Preparation, microstructure and sliding-wear characteristics of brush plated copper-nickel multilayer films

Cu/Ni multilayer films with sublayer thickness (h) ranging from 10 to 1000 nm were prepared on ANSI 1045 steel by brush plating of periodically changing layers of Cu and Ni. The microstructure, composition, microhardness and sliding wear properties against standard SiC ball under unlubricated condition were examined. It was found that the brush plated multilayer films are highly dense and free from porosity. A decrease in h results in smaller grain size and lower coefficient of friction. Both microhardness and wear resistance reach the maximum value when h = 20 nm. Although found with lower hardness compared with brush plated Ni monolayer coating, multilayer films with h ranging from 20 to 80 nm showed improved wear resistance. The increase in the wear resistance was attributed to the combined effect of strengthening of the layer structure and the lubricating of Cu.     

风力发电机传动系统的润滑油改性

利用基液置换法,将稳定性较好的磁流变体作为润滑油添加剂,以合理的配比加入到润滑油中,并对合成后的润滑油进行黏度测量及摩擦性能测试。由于稳定的磁流变体具有较宽的使用温度范围,良好的抗沉降团聚稳定性能,以及良好的润滑抗磨损性能,可以作为润滑油的添加剂,以适当提高润滑油黏度,降低磨损。实验及测试结果表明,磁流变体添加剂质量分数在3%~5%之间,最大无卡咬负荷为80kg~100kg,磨斑直径为0.48mm~0.51mm。稳定的磁流变体可以应用于风力发电机传动系统中的润滑,且添加剂质量分数在3%~5%的范围。     

填料粒度对汽车制动摩擦材料性能的影响

目的研究填料粒度对树脂基汽车制动摩擦材料性能的影响。方法选取硅酸锆、氧化铝、石墨和蛭石作为填料,树脂基摩擦材料采用热压成型法制成,在X-DM摩擦试验机上进行摩擦磨损试验。采用正交试验法,对填料粒度不同的树脂基摩擦材料的摩擦因数标准差和高温磨损率进行极差分析,以获得填料粒度组合最佳的摩擦材料配方。采用扫描电子显微镜对该材料和未经过粒度优化材料在不同温度下的磨损表面形貌进行对比分析。结果随着硅酸锆和氧化铝颗粒尺寸的增大,摩擦因数和高温磨损率均增大,但硅酸锆和氧化铝颗粒尺寸过大或过小都会造成摩擦因数的稳定性变差;石墨粒度变化对摩擦因数的稳定性影响不大,随着石墨颗粒尺寸的增大,高温磨损率减小;随着蛭石颗粒尺寸的增大,摩擦因数的稳定性变差,且高温磨损率增大。结论硅酸锆和氧化铝粒度在320~400目之间,石墨粒度在100~200目之间,蛭石颗粒尺寸小于80目为最佳的粒度组合,制成的摩擦材料的摩擦磨损性能最佳,试样的摩擦因数稳定,高温磨损率较低,抗热衰退性能好。     

Influence of Plasma Intensity on Wear and Erosion Resistance of Conventional and Nanometric WC-Co Coatings Deposited by APS

The effects of plasma intensity and powder particle size on wear and erosion resistance have been evaluated for WC-12 wt.%Co coatings deposited by Air Plasma Spraying. Coatings were deposited from micrometric and nanostructured powders. SEM and XRD characterization showed the presence of WC, W₂C, W, and an amorphous Co-rich matrix. The performance of the different coatings was compared in sliding wear tests (ball-on-disk), under dry friction conditions. Wear debris and tracks were analyzed by SEM. The debris generated during the test was found to have a great influence on the sliding properties. Wear follows a “three-body abrasive mechanism” and is dominated by coating spallation because of sub-surface cracking. In order to evaluate erosion behavior, solid particle erosion tests were conducted. Eroded coatings were analyzed by SEM, and erosion mainly occurs by a “cracking and chipping mechanism.” The study shows that wear and erosion behavior is strongly affected by plasma arc intensity.     

Aluminum-silicon carbide coatings by plasma spraying

An aluminum base composite (Al-SiC) powder has been developed for producing plasma sprayed coatings on Al and other metallic substrates. The composite powders were prepared by mechanical alloying of 6061 Al alloy with SiC particles. The concentration of SiC was varied between 20 and 75 vol%, and the size of the reinforcement was varied from 8 to 37 μm in the Al-50 vol% SiC composites. The 44 to 140 μm composite powders were sprayed using an axial feed plasma torch. Adhesion strength of the coatings to their substrates were found to decrease with increasing SiC content and with decreasing SiC particle sizes. The increase in the SiC content and decrease in particle size improved the erosive wear resistance of the coatings. The abrasive wear resistance was found to improve with the increase in SiC particle size and with the SiC content in the composite coatings.     

Tribological performance of Cu−Ni alloy nanoparticles synthesized using a pulsed-wire evaporation method

Cu−Ni alloy nanoparticles were produced using a pulsed-wire evaporation method in Ar gas. The synthesized Cu−Ni alloy nanoparticles had an average size of 150 nm, were spherical in shape and agglomerated. We investigated the tribological propeties of dispersion-stabilized Cu−Ni alloy nanoparticles when used as a solid lubricant in oil at ambient temperature. The sedimentation behavior of Cu−Ni alloy nanoparticles in oil was examined using Turbiscan LAb. The particles were clearly quantified using delta backscattering profiles and peak thickness kinetics as functions of time. The rubbing surfaces were characterized after a friction test using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). We found that dispersed Cu−Ni nanoparticles as a solid lubricant in oil had superior dispersion stability properties for over 48 h. Dispersed Cu nanoparticles in oil showed a low friction coefficient and good wear rate compared to oil only. Dispersed Cu−Ni alloy nanoparticles had superior friction reduction and antiwear properties compared to Cu nanoparticles, and these effects increased with the Ni content in the alloy. However, non-dispersed Cu−Ni alloy nanoparticles had poor antiwear properties. Dispersion-stabilized Cu−Ni alloy nanoparticles in oil enhanced the rolling effect of spherical nanoparticles between rubbing surfaces during friction processes.     

树脂基摩擦材料耦合机理研究

目的提高树脂基摩擦材料的机械性能和摩擦磨损性能。方法利用纤维的协同耦合效应制备混杂纤维增强材料,通过正交实验法设计配方,探究混杂纤维对摩擦材料性能的影响。借助扫描电镜对磨损表面和磨屑的微观形貌进行分析,使用能谱分析其元素组成,以探究摩擦材料的耦合机理。结果混杂纤维含量从8%增加到10.5%,摩擦材料的洛氏硬度和剪切强度分别维持在50～75 HRB、11.5～16.5 MPa适宜范围内,其中S3试样的洛氏硬度最大,为71 HRB,S4试样的剪切强度最大,为16.1 MPa。混杂纤维的交叉耦合效应决定了摩擦材料的机械性能。碳纤维在接触表面形成一层转移膜,发挥着润滑降温的作用,对摩擦材料的摩擦系数及磨损率均影响最大。结论转移膜的形成可有效缓解热衰退现象。适宜含量的混杂纤维可使摩擦表面形成连续的转移膜,且粒径细小的磨屑可提高转移膜的自洁性,从而降低摩擦材料的磨损率。磨损机理也由磨粒磨损和粘着磨损转变为多种机理综合的磨损形式。     

烷基胺边缘功能化氧化石墨烯Pickering乳液的摩擦学行为

为探究氧化石墨烯（GO）在金属加工液领域的应用潜能,采用改进Hummers法合成了GO,对其进行正辛胺的边缘功能化修饰,并构建了基于功能化GO的Pickering乳液。研究了功能化GO在液-液界面的油水界面行为,以及GO基Pickering乳液在固-液界面的摩擦学行为。利用全自动界面张力仪研究了功能化GO在不同油水界面的界面张力;利用UMT-tribolab和白光干涉仪研究了GO基Pickering乳液在CoCrMo合金和304不锈钢表面的界面润滑性能;利用Micro-Raman和XPS分析金属摩擦副表面的润滑膜组成,以阐明GO基Pickering乳液的润滑作用机理。研究结果表明：GO基Pickering乳液比空白乳液的减摩性能好,且胺功能化GO在CoCrMo合金上比在304不锈钢上展现出更优的润滑性能。对比空白乳液,在对摩擦副为CoCrMo合金时,GO乳液可降低35.9%的平均摩擦因数和46.7%的钢球磨损率,而Oct-N-GO乳液则可降低48.7%的平均摩擦因数和73.0%的钢球磨损率。机理分析表明,功能化GO良好的界面润湿性能使其所构建的Pickering乳液可以在金属表面形成良好的界面润滑膜;其结构中的烷基胺在摩擦过程中更易发生剪切,降低界面剪切力而起减摩作用;同时,其所形成的润滑膜组分中含有较高的C-O-C/C-OH和C=O,更好地吸附或填补到金属表面而起抗磨作用。     

Study on Friction Reducing and Anti-wear of CaCO_3 Nanoparticles as Additives in Lubricating Oils

THE NANOMETER PARTICLES?100nm)aremetastable materials that lie between macroscopicalmaterials and atoms or molecules with thecharacteristics of little size effect,quantummeasurement effect,surface effect and macroscopicalquantum tunnel effect etc.,thus demonstrating somespecial properties.Recently,much attention has beenpaid to the application of nanometer particles due to itsspecial properties,such as low melting point,low bulkdensity and large specific surface area.For example,owing …     

离子液体添加剂对润滑剂摩擦和润滑性能的影响

目的研究离子液体作添加剂时对基础润滑剂成膜能力和摩擦磨损性能的影响。方法选取聚α烯烃(PAO8)和锂基脂作为基础润滑剂,用季膦盐油酸离子液体作为添加剂,用UMT-3型多功能摩擦磨损试验机(UMT)进行实验,并对试验后的试样表面进行SEM分析。同时用光干涉点接触润滑油膜厚度测量装置测量其膜厚,通过对比基础润滑剂与添加离子液体后的摩擦系数、膜厚和磨斑,评价离子液体添加剂对基础润滑剂摩擦润滑性能的影响。结果相比于基础油和基础脂,离子液体作添加剂可以有效地降低摩擦磨损。含有离子液体添加剂的润滑剂有更高的油膜厚度,在高载荷工况下更明显。添加离子液体可以有效减轻基础油的乏油程度。结论离子液体添加剂可以有效减小摩擦磨损,提高润滑性能。     

Mechanical properties and friction−wear characteristics of VN/Ag multilayer coatings with heterogeneous and transition interfaces

The heterogeneous multilayer interface of VN/Ag coatings and transition multilayer interface of VN/Ag coatings were prepared on Inconel 781 and Si(100), and the microstructures, mechanical and tribological properties were investigated from 25 to 700 °C. The results showed that the surface roughness and average grain size of VN/Ag coatings with transition multilayer interface are obviously larger than those of VN/Ag coatings with heterogeneous multilayer interface. The coatings with transition multilayer interface have higher adhesion force and hardness than the coatings with heterogeneous multilayer interface, and both coatings can effectively restrict the initiation and propagation of microcracks. Both coatings have excellent self-adaptive lubricating properties with a decrease of friction coefficient as the temperature increases, but their wear rates reveal a drastic increase. The phase composition of the worn area of both coatings was investigated, which indicates that a smooth Ag, Magnéli phase (V₂O₅) and bimetallic oxides (Ag₃VO₄ and AgVO₃) can be responsible to the excellent lubricity of both coatings. To sum up, the coatings with transition multilayer interface have excellent adaptive lubricating properties and can properly control the diffusion rate and release rate of the lubricating phase, indicating that they have great potential in solving the problem of friction and wear of mechanical parts.     

Ni-P金刚石化学复合镀层制备及摩擦磨损性能分析

目的研究不同粒径微米金刚石对Ni-P金刚石化学复合镀层摩擦磨损性能的影响。方法选择出一组优良的Ni-P化学镀工艺参数,在镀液中分别加入不同粒径的金刚石微粒,制备含不同粒径微米级金刚石颗粒的化学复合镀层。用SEM和XRD,观察并分析了不同粒径金刚石对热处理前后Ni-P金刚石化学复合镀层微观形貌和组织结构的影响;通过硬度和摩擦磨损实验,研究了不同粒径金刚石颗粒对复合镀层硬度及摩擦磨损性能的影响。结果制备的复合镀层厚度为30μm左右,金刚石质量分数达到21%~25%,且金刚石均匀分散在Ni-P镀层中。热处理前镀层为非晶结构,经过400℃×2 h的热处理后,镀层晶化为硬度更高的Ni3P。金刚石能提高镀层硬度,其中粒径为9μm的复合镀层硬度最高,达到1261HV。Ni-P金刚石复合镀层的摩擦系数为0.4~0.52,随着金刚石粒径的增大,摩擦系数不断减小。金刚石使镀层的磨损机制发生了变化,随着金刚石粒径的增大,硬质合金球的磨损加剧。结论随着金刚石粒径的增大,镀层硬度增加,摩擦系数减小,耐磨性增大。     

Bio-mimetic surface structuring of coating for tribological applications

A novel multilayered coating was developed for applications associated with friction reduction and wear resistance improvement. The nano-engineered coating integrates a soft lubricating layer, consisting of MoS₂-PTFE, onto hard load-supporting layers, with controlled surface morphology (roughness and patterning) of cBN-TiN. The coating was synthesized by sequential procedures including electrostatic spray deposition of cBN particles with different average particle sizes, chemical vapor deposition of TiN, deposition of nano- and micro-sized MoS₂ dispersed in PTFE, and curing. The effect of cBN particle size (with different combinations of particle size) and deposition parameters (specifically electrical voltage) on the cBN-TiN surface morphology were studied experimentally and optimized. SEM characterization of the as-synthesized cBN-TiN coating shows surface features similar to that of colocasia esculenta, with alternating nano- and micro-sized domes and “pockets”; the MoS₂-PTFE top layer has MoS₂ particles retained in the pockets by a basket structure formed during PTFE curing. Tribological and scratch tests were carried out for the as-prepared cBN-TiN and cBN-TiN/MoS₂-PTFE multilayered coatings. Sliding test results demonstrate significantly lower friction coefficient for the multilayered coating, showing that the unique integration of soft lubricating layer and biomimetically structured hard layer can effectively improve tribological performance. It is suggested that lubrication at the frictional contacts was realized by continuous release of the lubricants, MoS₂ and PTFE, from the pockets.     

三维石墨烯作为润滑油添加剂的抗断油性能研究

目的设计三维网状石墨烯(3D framework carbon, 3DFC)作为PAO-6基础油添加剂,改善基础油的摩擦磨损性能,提高基础油的抗断油能力。方法使用十八胺修饰得到亲油的3DFCs,将0.001g 3DFCs粉末添加到10 g PAO基础油中,超声分散30 min,得到稳定分散的3DFCs润滑油。利用场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、能量分散X射线仪(EDX)、傅里叶变换红外光谱仪(FTIR)和拉曼光谱仪(Raman)分析了3DFCs的微观形貌和结构。利用CSM摩擦试验仪器评估了3DFCs作为基础油添加剂的摩擦学性能,并用扫描电镜、拉曼光谱对磨斑及磨痕成分进行了分析。结果经十八胺修饰的3DFCs的亲油性得到提高,可在PAO-6基础油中稳定分散。3DFCs作为PAO-6基础油添加剂(0.01%),在非断油摩擦情况下,其磨损率较PAO-6基础油降低了约1个数量级,而较0W-50机油并未降低。在断油摩擦情况下,PAO-6基础油和0W-50机油易发生摩擦失效,3DFCs润滑油能保持平稳有效摩擦,其抗断油性能最优。结论具有三维结构、石墨层间距大、润滑性能优异的3DFCs作为润滑油添加剂,具有良好的抗断油能力,可以有效地保护摩擦部件免遭损坏。     

含纳米金刚石润滑油减摩抗磨添加剂的摩擦学性能

研制了一种含纳米金刚石润滑油节能抗磨添加剂，对其摩擦学性能及机制进行了研究。结果表明：所研制的含纳米金刚石润滑油抗磨添加剂上有优异的摩擦学性能，摩擦表面存在含金刚石的表面膜。