多孔阵列阳极氧化铝膜润滑性能的Stribeck研究

为了研究阳极氧化铝膜的多孔结构对其润滑性能的影响,分别制备了光滑表面氧化铝膜,40 nm孔径、90 nm孔径多孔表面氧化铝膜.用接触角测试仪测试了水、机油与3种表面的接触角;在不同润滑条件下,用摩擦磨损试验机UMT-2测试了3种氧化铝膜与GCrl5钢面接触的润滑性能.结果表明:多孔结构氧化铝膜增强了材料的亲水性能和亲油性能,90 nm孔径氧化铝膜表现出超亲油特征;水润滑和机油润滑条件下,速度从0.016 m/s增至0.32 m/s过程中,光滑氧化铝表面只能形成边界润滑区域,多孔表面得到了包含边界润滑、混合润滑和流体润滑的完整的Stibeck曲线.机油润滑条件下,40 nm孔径的膜达到最小摩擦系数的临界速度为0.28 m/s,最小摩擦系数为0.083,90 nm孔径的膜达到最小摩擦系数的临界速度仅为0.2 m/s,最小摩擦系数减小为0.023;机油润滑条件下,90 nm孔径的氧化铝膜板的Stribeck曲线,谷底区域更宽.     

外加电对边界油润滑下摩擦系数的影响

利用外加电压实现对摩擦系数的主动控制是摩擦学者长期追求的目标之一．本实验应用球盘式摩擦试验机，针对150SN油润滑下的GCrl5／45″摩擦副，考察了外加直流电压极性、外加直流电流大小、以及外加交流电压的频率对其摩擦和润滑性能的影响，并对其作用机理进行了分析．实验结果表明，外加直流电压的极性对GCrl5／45″摩擦副间的摩擦系数和润滑状况有很大的影响；一定范围内的外加电流大小的影响只是程度上的不同而已；外加交流电压的影响则综合了由极性和幅值的变化所带来的影响，其变化频率也是重要的摩擦学性能影响参数．结合作者先前的工作及其他有关文献，对外加电压的影响机理进行了初步分析，认为外加电是通讨影响界面摩擦电化学反应所形成的表面氧化膜的性质和状态来影响摩擦和润滑性能的．     

脉冲真空电弧离子镀沉积类金刚石薄膜的结构和力学性能研究

利用脉冲真空电孤离子镀技术在3Cr13不锈钢上制备了类金刚石(DLC)薄膜．通过Raman光谱分析了膜的结构特征，采用摩擦磨损试验机测试了薄膜在不同载荷下的摩擦系数，运用划痕仪研究了膜基的结合强度．结果表明：所镀制的薄膜具有典型类金刚石结构特征，膜中ID／IG为1．33；摩擦系数随着载荷的增大而减小，载荷为5N，转速120r／min时的摩擦系数为0．02；Ti过渡层的引入显著地提高了膜基结合力．     

改变过渡层碳靶功率在铜上沉积类金刚石膜的研究

类金刚石膜具有硬度高、 摩擦系数低、 耐腐性强、 稳定性高等优点, 是提高铜耐腐性的理想材料, 但铜 与类金刚石膜之间的结合力差。通过制备T i xC y 过渡层, 采用磁控溅射物理气相沉积与化学气相沉积法, 通过改变 过渡层碳靶功率成功在铜基体上沉积类金刚石膜。并对金刚石膜进行拉曼光谱测试、 划痕实验和电化学实验分析。 结果表明, 所制备碳膜具有典型的类金刚石结构, 膜与基体之间的结合强度大, 过渡层碳靶溅射功率为2 0 0W 时所 制备的类金刚石膜对铜基体的保护作用最好。     

Tribological characteristics and self-repairing effect of hydroxy-magnesium silicate on various surface roughness friction pairs

Tribological characteristics and self-repairing effect of hydroxy-magnesium silicate (HMS) dispersed in lubricant oil on steel-to-steel friction pairs with various surface roughness were analyzed. The friction-reduction, anti-wear and self-repairing performance of various surface roughness friction pairs were examined by friction testing machine. An operation comparison was made between SJ10W-40 lubricant with and without HMS. The surface morphology and elementary composition of the grinding cracks were analyzed by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results show that the lubrication state changes from boundary lubrication into mixed lubrication after operation in lubricant with HMS. The friction-reduction, anti-wear and self-repairing performance of the friction pairs with various surface roughness are distinctly different. There is a repairing film whose material is different from substrate material on the grinding cracks. In addition, Si, Mg, O, Al and other elements are deposited on the repairing film which contains nanocrystals of these elements. And HMS self-repairing material possesses superior performance of friction-reduction, anti-wear and self-repairing effects.     

Preparation and Characterization of DLC Films by Twinned ECR Microwave Plasma Enhanced CVD for Microelectromechanical Systems （MEMS） Applications

Diamond-like carbon ( DLC ) films have recerntly been pursued as the protection of MEMS against their friction and wear. Plasma enhanced chemical vapor deposition (PECVD) technique is very attractive to prepare DLC coating for MEMS. This paper describes the preparation of DLC films using twinned electron cyclotron resonance (ECR) microware PECVD process. Raman spectra confirmed the DLC characteristics of the films.Fourier-transform infrared (FT-IR) characterization indicates the carbon is bonded in the form sp^3 and sp^2 with hydrogen partciputiag in bondiag. The surface rougbness of the films is as low as approximately 0.093nm measured with an utomic force microscope. 4 CERT mierotribometer system is employed to obtain information about the scratch resistance ,friction properties, and slidiag wear resistance of the films. The results show the deposited DLC films have low friction and good scratch/wear resistance properties.     

Study of lubrication behavior of pure water for hydrophobic friction pair

The perfluorooctyltrichlorosilane molecular layer was self-assembled on glass plate. The tribological properties of the molecular layer in water were studied with the method of ball on disk. An interesting phenomenon was found that low friction coefficients of 0.02–0.08 were obtained when the friction pair was lubricated with only a water droplet. Whereas, when the friction pair was encircled with large amount of water or fully immersed in water, the friction coefficient was higher than that under a droplet lubrication. A mechanism of water droplet lubrication was proposed that the surface tension caused by the solid-liquid-air three-phase interface makes water molecules enter into the contact zone, which separates the two friction surfaces and provides a low friction coefficient. However, water film can hardly form when more water encircles the friction pair, due to the attraction between water molecules.     

水环境下二硫化钼/聚四氟乙烯复合材料与石英玻璃的超润滑摩擦学特性

采用M-200型摩擦磨损试验机,对比研究了几种填充PTFE复合材料与石英玻璃对磨时,在水润滑、低速、较高载荷条件下的摩擦学特性。结果表明:在水润滑条件下,MoS2/PTFE复合材料与石英玻璃对磨时的摩擦系数可低于0.005,表现出超润滑摩擦特性,而且具有稳定的摩擦系数和很低的磨损率。石英玻璃所具有的优良表面特性和优异的亲水性是实现超润滑的关键。当添加高硬添料时,石英玻璃表面容易受到破坏,导致摩擦学性能下降。     

柱塞泵柱塞密封摩擦副润滑状态分析

根据流体动压润滑理论,对柱塞泵柱塞密封摩擦副的润滑机理进行了理论分析,即在泵的排出行程由强制性润滑油润滑,泵的吸入行程由工作介质润滑;并利用最小油膜厚度的计算公式,对摩擦副的润滑状态进行了判断。模拟计算表明,在柱塞往复运动周期内,摩擦副处于干、混合摩擦状态,工作介质和强制润滑油可改善润滑状态,且润滑油的选择也是至关重要的。     

Tribological Properties of MoSi2 Against AISI10045 Steel Under Sliding Friction

MoSi2 samples were prepared by a self-propagating high-temperature synthesis （SHS） and a hot-press technique. The sliding friction and wear properties of intermetallic MoSi2 against AISI10045 steel under dry friction and oil lubrication conditions were investigated with a MRH-5A type ring-on-block friction and wear tester. The elemental composition, microstructure and worn surface morphology of the MoSi2 material were observed and analyzed by means of scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The synthetic parameter pv value reflecting friction work, was used to discuss the tribological properties of MoSi2 material. The results show that 1） oil lubrication can obviously improve the tribological properties of MoSi2, 2） the bigger the pv value, the greater the antifriction and the abrasive resistance of MoSi2 under oil lubrication, 3） with an increase in the pv value, the wear mechanism of MoSi2 material under dry sliding friction is the fatigue fracture and adhesive wear and 4） under oil lubrication the wear mechanism is mainly fatigue pitting.     

Comparison of Biotribology of Swine Compact Bone Against UHMWPE

A pin-on-disk tribometer was used, in a comparative test to observe the tribological behavior of the swine femoral bone against UHMWPE with dry friction, physiological water and human plasma lubrication. The wear mechanisms of swine bones and UHMWPE were investigated by SEM. The experimental results of these wear tests demonstrated that both the friction coefficient and wear rate of UHMWPE were the lowest when human plasma lubrication was used. The wear mechanism of the compact bone was mainly fatigue wear with dry friction, corrosive wear under physiological water lubrication and abrasive wear with human plasma lubrication. For UHMWPE, the wear mechanism was adhesive wear and plastic deformation with dry friction, serious ploughing and fatigue fracture wear under physiological water lubrication, fine ploughing and plastic deformation with human plasma lubrication. An analysis of nitrogen elements on the wear surface of UHMWPE indicated that the content of nitrogen in worn areas was 16 times higher than that in unworn areas, which proved that serum protein deposition occurred on worn areas.     

谐波齿轮粗糙表面薄膜润滑计算

谐波齿轮传动齿面的润滑状态,考虑到表面粗糙度影响后,用基于平均流动模型的平均雷诺方程进 一步研究,推导薄膜润滑条件下齿面压力和油膜厚度的计算关系,计算剪切膜和挤压膜的数值解,给出齿面最小油 膜厚度曲线。结果表明,齿面表面粗糙度增大,由它所引起的动压效应增强,齿面上的润滑油易存留,能够建立起足 够的油膜厚度。     

H2对类金刚石薄膜性能影响的研究

类金刚石膜因其高的硬度、高的介电性、低的摩擦系数、优异的光学和化学性能以及巨大的潜在应用前景而成为研究热点。采用离子增加化学气相沉积方法在Si基底表面制备含氢类金刚石薄膜,通过XPS能谱测试,确定膜层的成份组成,膜层中除了含有碳以外还含少量的吸附的氧。调节反应源气体中H：的比例,结果表明H2的含量直接影响DLC薄膜的性能。随着H。的含量增大,膜层的表面粗糙度降低,膜层的硬度变大,而应力相应增大。这是由于反应源气体中H2含量的增加,DLC薄膜中氢的含量反而降低,膜层内sp2团簇结构的无序性增加,sp2键的比例增加,这将使得膜层内的碳的空间网络结构所占的比例增加。     

Tribological behavior of MC Nylon6 composites filled with glass fiber and fly ash

To improve tribological property of MC Nylon6,the glass fiber and fly ash reinforced monomer casting nylon composites(GFFAPA)were prepared by anionic polymerization of ε-caprolactam.The friction and wear behaviors of composites under dry condition,water lubrication and oil lubrication were investigated through a ring-black wear tester.Worn surfaces were analyzed using a scanning electron microscope.The experimental results show that the tensile strength and hardness of nylon composites are obviously improved with reinforcement increasing.Compared to MC nylon,the lowest friction coefficient and wear rate of glass fiber reinforced nylon composites(GFPA)with GF30% respectively decrease by 33.1% and 65.3%,of fly ash reinforced nylon composites(FAPA)with FA20% decrease by 5.2% and 68.9% and of GFFAPA composites with GF30% and FA10% decrease by 57.8% and 89.9%.The main wear mechanisms of FAPA composites are adhesive and abrasive wear and of GFPA composites with high proportion are abrasive and fatigue wear.The worn surfaces of GFFAPA composites are much multiplex and the optional distributing glass fiber and fly ash have a synergetic effect on the wear resistance for GFFAPA composites.Compared with dry friction,the friction coefficient and wear rate under oil lubricated conditions decrease sharply while the latter reversely increase under water lubricated conditions.The wear mechanisms under water lubricated condition are principally chemical corrosion wear and abrasive wear and they become boundary friction under oil lubricated condition.     

Tribological properties of CrN coating deposited on 20CrMo against tin bronze

A CrN coating was deposited on the piston pin material 20CrMo. The tribological properties of 20CrMo and CrN coating against tin bronze QSn7-0.2 were compared by pin-on-disk tests under dry friction and oil lubrication, respectively. The cross-sectional morphologies and structures of the coating were characterized through scanning electron microscopy and X-ray diffraction. The hardness, elastic modulus, and adhesion strength of the coating were tested through nano-hardness and scratch tests. The wear tracks were tested with an optical profilometer, and wear volume was calculated. Under dry friction conditions, the CrN coating exhibited a significantly stable friction coefficient and a relatively lower wear rate against QSn7-0.2 at various temperatures compared with 20CrMo. The wear rate decreased by 98.5% at 700°C. Under poly-alpha-olefine lubrication, the CrN coating reduced the load effect on the friction coefficient. Under engine oil 5 W40 lubrication, the CrN coating improved the tribological properties under high speed and heavy load conditions. Simultaneously, the CrN coating changed the friction and heat flow with increasing temperature.     

GCr15球-盘点接触摩擦副的滑滚摩擦磨损特性研究

选用GCr15钢盘和GCr15球作为摩擦副,在NGY‐6纳米润滑膜测量仪上开展球‐盘点接触摩擦副在润滑状态下的滑滚摩擦磨损实验,研究不同接触应力、钢球转速、滑滚比等参数对摩擦副的摩擦因数、磨损形貌的影响规律．结果表明：当接触应力和钢球转速一定时,摩擦因数随着滑滚比的增大而逐渐增加后达到稳定状态;当滑滚比一定时,摩擦因数随接触应力的增大而逐渐增大;当钢球转速低于300 r／min时,摩擦因数随着钢球转速的增大而减小;当钢球转速高于300 r／min、接触应力大于0．84 GPa时,摩擦因数随着钢球转速的增大而呈增大趋势．Stribeck曲线表明：当滑滚比为0．01时,摩擦副处于流体动压润滑状态;当滑滚比为0．03时,润滑状态随Sommerfield参数的增加而从边界润滑过渡到混合润滑;当滑滚比分别为0．05、0．1、0．3、0．5时,润滑状态为边界润滑．滑滚比较小时,磨损机制以疲劳磨损为主,随着滑滚比的增大,磨损机制转变为磨粒磨损．     

蜗杆传动的润滑

本文根据摩擦磨损润滑学理论分析了蜗杆传动的三种基本润滑状态:液体润滑、边界润滑和干摩擦状态;说明这三种基本润滑状态中,液体润滑是一种理想的润滑状态。在此基础上,分析了蜗杆传动实现液体润滑的几何条件、润滑条件及传动条件,并通过对油膜比厚的分析,说明提高啮合表面光洁度对实现液体润滑的作用。作为实例,本文还分析了普通圆柱蜗杆(传动)的传动特点及其不同的润滑状态,说明选用合适的润滑油对提高普通圆柱蜗杆(传动)使用寿命的重要作用。     

基于鸟翼轮廓的沟槽型织构润滑性能分析

为减小车辆行星齿轮双向旋转轴向滑动支承磨损,将仿生学理念引入支承端面微织构的设计,将空气动力学优良的鸟翼结构抽象简化为抛物线槽,双抛物线三角形槽以及双抛物线梯形槽三种基本的槽型,建立基于质量守恒边界条件的空化效应数值模型,从而分析比较不同槽型的工况参数和结构参数对润滑特性的影响。研究结果表明基于仿生的这三种槽型中,双抛物线三角形槽的油膜承载力和摩擦系数最优,双抛物线梯形槽的润滑油流量和空化率最优,抛物线槽的的各项润滑性能没有太优异的也没有太差的,但其综合润滑性能在三者中最优。     

滚动轴承式行星摩擦传动弹流研究

运用弹性流体动力润滑理论推导出了滚动轴承式行星摩擦传动润滑最小油膜厚度公式.根据公式作出了最小油膜厚度与转速的关系曲线和最小油膜厚度与球径的关系曲线,由关系曲线得出:转速越高和选用较大的轴承直径系列,均有助于油膜的形成.     

不同工况下丁腈橡胶的摩擦磨损机理

为了合理选择螺杆泵定子橡胶材料以提高螺杆泵的使用寿命,分析了不同工况下丁腈橡胶与金属配副的摩擦磨损机理.采用MPV-600环块式摩擦磨损试验机对不同炭黑质量分数的丁腈橡胶在变载荷情况下进行摩擦磨损试验,利用体视显微镜观察橡胶磨损后的表面形貌,使用红外光谱仪分析表面官能团变化.试验结果表明:干摩擦情况下,磨损量在一定炭黑质量分数范围内随其增加而减小,磨损机制为黏着磨损和磨粒磨损;水润滑情况下,由于水的润滑及冷却作用,炭黑质量分数适中的橡胶耐磨性最好,磨损机制为磨粒磨损;原油润滑低载荷情况下,磨损量几乎不受炭黑质量分数的影响,而高载荷情况下,炭黑质量分数越高,磨损量越小,其磨损机制以腐蚀磨损为主.