A Comparative Study on the Tribological Behavior of Nanocrystalline Nickel and Coarse-grained Nickel Coatings under Ionic Liquid Lubrication

Tribological properties of nanocrystalline (NC) nickel coating and coarse-grained nickel coating were evaluated using a ball-on-flat sliding tester. Results indicated that the NC nickel coating had excellent tribological properties. This was partly attributed to the high hardness of the NC nickel coating and the tribochemical interactions between rubbing pairs and ionic liquid.     

Effect of Flash Temperature on Tribological Properties of Bulk Metallic Glasses

The tribological properties of Cu-based and Zr-based bulk metallic glasses (BMGs) sliding against Si₃N₄ under dry and water lubrication were studied on a pin-on-disc tribometer. The wear mechanisms of bulk metallic glasses were investigated based on the calculated flash temperature. The friction coefficients if fully amorphous alloy are about 0.7, while those of BMGs with nanocrytalline are a little higher. The wear rates of Cu-based BMG (V101) are about one order of magnitude lower than those of Zr-based BMG (Vit1) under dry friction, even two orders of magnitude lower under water lubrication. The wear resistance of bulk metallic glasses was influenced by the flash temperature. The calculated flash temperature (3,337 K) on the friction surface of Zr-based amorphous alloy exceeds its glass transition temperature, even its melting temperature. The high flash temperature leads to glass transition accompanied with viscous flow and material transfer, which is responsible for the poor wear resistance of Zr-based BMGs.     

Investigation of the Stability and Tribological Performance of Ionic Nanoliquids

In previous studies, nanoparticles and ionic liquids (ILs) have been used separately as oil additives and have been shown to reduce friction and wear. In this study, the stability and tribological performance of ionic nanoliquids (INLs), which combine nanoparticles and miscible ionic liquids together as oil additives, were investigated. Zinc oxide nanoparticles were dispersed in a mixture of polyalphaolefin (PAO) oil and ionic liquid (tetradecyltrihexylphosphonium bis (2,4,4-trimethylpentyl phosphinate)) using an ultrasonic homogenizer. The coefficient of friction was studied using a tribometer with a ball-on-disk configuration. The wear track was measured using a Bruker Contour GT-K Optical Profiler and the wear volume was calculated. The effects of concentration and load on the coefficient of friction and wear were investigated. The effects of ultrasonic mixing time and nanoparticle concentration on the stability of the solutions were also studied.     

石墨烯/MoS2复合涂层多环境下的摩擦学性能

以MoS2作为润滑剂,以石墨烯(GE)作为润滑添加剂,采用喷涂法在GCr15钢样片表面制备不同含量的GE/MoS2复合涂层.利用HSR-2M型高速往复式摩擦磨损试验机测试涂层在干摩擦及海水环境中的摩擦磨损性能,并分析了磨痕形貌及磨损机制.结果表明:添加适量石墨烯可明显改善MoS2涂层的摩擦磨损性能,且海水环境中涂层的摩...     

Effect of the Anion on the Tribological Properties of Ionic Liquid Nano-Films on Surface-Modified Silicon Wafers

The films of three kinds of 3-butyl-1-methylimidazolium base ionic liquids with thickness of 2 nm were prepared on hydroxyl-terminated and amino-terminated Si substrates by dip-coating method. As anions, tetrafluoroborate, hexafluorophosphate, and adipate, respectively, were chosen. The tribological performances of these thin films were examined by the determination of the film durability and friction coefficient by means of a UMT-2MT tribometer using a steel ball as counterpart. The morphologies of worn surfaces were investigated by a non-contact interferometric microscope. The findings showed that 3-butyl-1-methyl-imidazolium hexafluorophosphate having the poorest hydrophilicity of the ionic liquids exhibited the best tribological properties on aminated Si surface at 0.4 N and 4 Hz.     

镍基Si3N4复合镀层的摩擦磨损特性

通过复合电镀法制备了N i-Si3N4和N i-P-Si3N4两种复合镀层,分别与热处理45#钢组成摩擦副,进行环-环摩擦磨损试验,测试了摩擦因数和磨损量,并观察了磨损表面形貌,探讨了摩擦副的摩擦磨损机理。结果表明,N i-P-Si3N4/45#钢摩擦副的摩擦因数较小,磨损量低,具有良好的减摩耐磨性能。镀层基体的性能明显影响复合镀层的摩擦磨损性能。磨料磨损是N i-Si3N4/45#钢摩擦副的主要磨损形式,导致45#钢的磨损量增大;N i-P-Si3N4镀层对Si3N4颗粒具有良好的把持力,避免了磨料磨损的产生,摩擦副处于稳定的边界润滑摩擦状态。     

Nano/Microtribological Properties of Ultrathin Functionalized Imidazolium Wear-Resistant Ionic Liquid Films on Single Crystal Silicon

Ionic liquids (ILs) are considered as a new kind of lubricant for micro/nanoelectromechanical system (M/NEMS) due to their excellent thermal and electrical conductivity. However, so far, only few reports have investigated the tribological behavior of molecular thin films of various ILs. Evaluating the nanoscale tribological performance of ILs when applied as a few nanometers-thick film on a substrate is a critical step for their application in MEMS/NEMS devices. To this end, four kinds of ionic liquid carrying methyl, hydroxyl, nitrile, and carboxyl group were synthesized and these molecular thin films were prepared on single crystal silicon wafer by dip-coating method. Film thickness was determined by ellipsometric method. The chemical composition and morphology were characterized by the means of multi-technique X-ray photoelectron spectrometric analysis, and atomic force microscopic (AFM) analysis, respectively. The nano- and microtribological properties of the ionic liquid films were investigated. The morphologies of wear tracks of IL films were examined using a 3D non-contact interferometric microscope. The influence of temperature on friction and adhesion behavior at nanoscale, and the effect of sliding frequency and load on friction coefficient, load bearing capacity, and anti-wear durability at microscale were studied. Corresponding tribological mechanisms of IL films were investigated by AFM and ball-on-plane microtribotester. Friction reduction, adhesion resistance, and durability of IL films were dependent on their cation chemical structures, wettability, and ambient environment.     

Tribological behavior of sialon ceramics sliding against steel lubricated by fluorine-containing oils

The friction and wear behavior of sialon ceramics sliding against steel and lubricated by perfluoropolyethers (PFPE), tetrakis (3-trifluoromethylphenoxy)-bis(4-fluoro-phenoxy)-cyclotriphosphazene (X-1P) and ionic liquid (1-methyl-3-octylimidazolium tetrafluoroborate, coded as L108) were investigated. It was found that the three fluorine-containing lubricants reduced friction coefficient and wear volume effectively. The effectiveness of the three lubricants in reducing wear volume could be ranked as L108>X-1P>PFPE. The antiwear films mainly consisting of organic oxyfluoride or carbonfluoride species and silicon fluoride are all observed for the three lubricants, while the degradation of PFPE during friction might account for the higher wear volume therewith. The lowest friction coefficient 0.065 was recorded for L108 under load of 0.5–400 N. This is dependent on the physically adsorbed ionic liquid on the rubbing surface and the formation of BN under the harsh conditions.     

Tribological properties of plasma nitrided stainless steel against SAE52100 steel under ionic liquid lubrication condition

1Cr18Ni9Ti stainless steel was modified by plasma nitriding. The phase composition of the plasma nitrided layer was examined by means of X-ray diffraction. The friction and wear properties of the modified and unmodified 1Cr18Ni9Ti stainless steel specimens sliding against SAE52100 steel under the lubrication of ionic liquid of 1-ethyl-3-hexylimidazolium hexafluorophosphate (L-P308) and poly α-olefin (PAO) were investigated on an Optimol SRV oscillating friction and wear tester, with the interactions among the modified surface layer and the ionic liquids and PAO to be focused on. The morphologies of the worn surfaces were observed using a scanning electron microscope. The chemical states of several typical elements on the worn surfaces of the modified steel surfaces were examined by means of X-ray photoelectron spectroscopy. Results showed that the modified sample had better anti-wear abilities than the unmodified one, but the modified sample had a slightly higher friction coefficient than the untreated one. This was partly attributed to the change in the hardness and phase composition of the stainless steel surfaces after plasma nitriding and tribochemical reactions between the steel and the lubricant. The resultant surface protective films composed of various tribochemical products together with the adsorbed boundary lubricating film contributed to reduce the friction and wear.     

水润滑橡胶/镀镍钢配副摩擦磨损机理研究

对水润滑轴承专用橡胶／镀镍钢配副分别在干摩擦、边界润滑条件下用数显式高速环块摩擦磨损试验机进行了摩擦磨损试验，并借助SEM分析了其摩擦磨损机理。结果表明：千摩擦条件下主要为粘着磨损，边界润滑条件下主要为磨粒磨损。     

不同石墨烯添加量下MoS2基复合涂层的摩擦磨损及耐腐蚀性能

为改善MoS2基固体润滑涂层的摩擦磨损性能和耐蚀性能,制备了不同石墨烯（GE）添加量的MoS2复合涂层,利用HSR-2M摩擦磨损试验机测试了复合涂层的摩擦磨损性能,并分析了其磨损机理,通过极化曲线、交流阻抗谱（EIS）研究了涂层在3.5%NaCl溶液中的电化学腐蚀行为。试验结果表明,0.8-GE/MoS2复合涂层的摩擦磨损和耐腐蚀性能最优,其平均摩擦因数和磨损率分别为0.232和2.379×10-13 m3/(N·m),较未添加石墨烯的MoS2涂层分别降低了49.56%和43%,腐蚀速率（1.96×10-8 A/cm2）较纯MoS2涂层（5.54×10-6 A/cm2）降低了近2个数量级。石墨烯的二维片状结构具有良好的自润滑性能,在涂层中均匀分布时能有效阻隔腐蚀介质的渗透,因此,石墨烯的添加提高了MoS2基复合涂层的摩擦学性能和耐腐蚀性能,石墨烯的最优添加量为0.8%（质量分数）。     

Ni-Fe-W合金镀层的结构形貌及摩擦学性能研究

利用脉冲电沉积的方法制备了Ni-Fe-W合金镀层,讨论了镀液中W的含量对Ni-Fe-W合金镀层组织结构的影响,以及镀液成分对镀层硬度及厚度的影响。分析了Ni-Fe-W合金镀层在干摩擦条件下摩擦因数随载荷以及速度的变化情况,并与Ni-W合金镀层以及硬铬镀层进行了比较,探讨了干摩擦条件下Ni-Fe-W合金镀层的摩擦磨损机制。在高速轻载时,Ni-Fe-W合金镀层在摩擦过程中会生成有弥散强化作用的中间硬质相和起固体润滑作用的氧化物,使其磨损表现为轻微的磨粒磨损。     

温度对火焰喷涂FEP涂层制备及摩擦学性能的影响

利用火焰喷涂在不同预热温度制备了FEP涂层，评价了环境温度对涂层摩擦学性能的影响，并对涂层进行了XRD、SEM等分析。结果表明：FEP涂层的最佳预热温度为270℃，此时涂层与基材的结合面上缺陷很少。FEP粉末和涂层中都含有无定形和结晶相，形成涂层后的结晶度有了明显的提高；环境温度在200℃以下时，涂层摩擦因数变化不大；200℃以后摩擦因数迅速增大，且涂层的磨损率随着环境温度的升高而增大；在较高的环境温度下，涂层的磨损呈现出明显的疲劳磨损特征。     

微波辅助液相还原法制备针状纳米镍及其摩擦学性能研究

采用液相化学还原法,在水体系中,以醋酸镍为前驱体,水合肼为还原剂,氢氧化钠为pH值调节剂,引入微波辐照,加入适量自制表面活性剂为修饰剂,合成了长85～95nm、直径为3～6nm的针形纳米镍。通过X-射线衍射(XRD)、透射电子显微镜(TEM)和热重-差热分析(TG-DSC)对纳米镍进行了表征。将所制备的纳米镍添加到成品润滑油15W/40SF汽油机油中,考察了添加前后润滑油的摩擦学性能。结果表明:添加纳米镍后较大程度地降低了成品润滑油的摩擦因数,显著改善了成品润滑油的摩擦学性能;添加量的增加对润滑油摩擦性能的改善略有提高,但提高不大。     

超声辅助电火花粉末沉积WC-Ni金属陶瓷涂层的微观结构及摩擦学性能

针对传统电火花沉积工艺中工具电极预制成本高、工艺复杂、材料选择范围受限等问题,提出了一种超声辅助电火花粉末沉积(Ultrasonic-assisted electro-spark powder deposition,UEPD)的新方法.利用UEPD工艺成功地在316L不锈钢基材上制备了 WC-Ni金属陶瓷涂层.所制备的...     

Tribological Performance Optimization of Electroless Ni–P Coatings Using the Taguchi Method and Grey Relational Analysis

The present article considers an experimental study of tribological performance of electroless Ni–P coatings and optimization of tribological test parameters based on the Taguchi method coupled with grey relational analysis. A grey relational grade obtained from the grey relational analysis is used as performance index to study the behaviour of electroless Ni–P coating with respect to friction and wear characteristics. Experiments are carried out by utilizing the combination of tribological test parameters based on L₂₇ Taguchi orthogonal design with three test parameters, viz., load, speed and time. It is observed that all the three test parameters have significant contribution in controlling the friction and wear behaviour of electroless Ni–P coating. In addition, the interaction of load and time has significant influence on tribological performance. The surface morphology, composition and wear mechanism of the coatings are studied with the help of scanning electron microscopy, X-ray diffraction analysis and energy dispersed X-ray analysis.     

羟乙基咪唑啉对矿物润滑油生物降解及摩擦学性能的影响

以液体石蜡模拟矿物润滑油基础油,考察羟乙基咪唑啉作为润滑油生物降解促进剂对液体石蜡生物降解性、抗磨减摩性、热稳定性、抗腐蚀性、防锈性的影响。结果表明：羟乙基咪唑啉可显著提高液体石蜡的生物降解性,其原因是羟乙基咪唑啉降低了油/水界面张力和加速了微生物生长;羟乙基咪唑啉还可在一定程度上改善液体石蜡的抗磨减摩性、抗腐蚀性和防锈性,且对液体石蜡热稳定性影响不大。     

Y2O3改性石墨/CaF2/TiC/镍基合金复合涂层微观组织与摩擦学性能研究

为提高石墨/CaF₂/TiC/镍基合金（GCTN）复合涂层的力学性能和摩擦学性能,运用等离子喷涂技术在45钢表面制备了Y₂O₃改性GCTN复合涂层,研究了Y₂O₃对复合涂层的微观组织、显微硬度、断裂韧性和摩擦磨损性能的影响。结果表明：Y₂O₃改性GCTN复合涂层主要由γ-Ni、CrB、Cr7C₃、TiC、CaF₂和石墨等物相组成。Y₂O₃在等离子火焰加热作用下与C元素反应生成活性元素Y,Y净化了复合涂层的微观组织,并细化了CrB、Cr₃C7等硬质相晶粒,提高了其致密性。当Y₂O₃质量分数为0.5%时,复合涂层的显微硬度和断裂韧性分别为593.3MPa和6.82MPa·m^1/2,比不含Y₂O₃的复合涂层分别增大了8%和22%,其机理主要是Y₂O₃细化了CrB、Cr₃C₇等硬质相晶粒,起到了细化强化作用。由于GCTN-0.5Y₂O₃复合涂层的显微硬度和断裂韧性显著提高,减少了其黏着磨损和微观断裂磨损,因而GCTN-0.5Y₂O₃复合涂层的摩擦因数和磨损率最小,分别为0.085和0.39×10-3mm3/m。