镍基WC陶瓷等离子喷涂涂层的干滑动摩擦磨损性能

研究了镍基WC陶瓷等离子喷涂涂层随载荷和速度变化的干滑动摩擦磨损性能，探讨了涂层的孔隙率、显微硬度及磨损面和磨损后涂层形貌与涂层的磨损机制之间的关系。研究表明：镍基WC涂层与对磨材料相比具有优良的摩擦磨损性能，且随着摩擦速度的增加，磨损率增加的幅度很小，摩擦因致减小的幅度较大，随着摩擦载荷的增加，摩擦因致减小和磨损率增加的幅度较小。     

径向滑动轴承的水润滑分析

针对工程中润滑膜膜厚难以直接准确测量问题,本文采用数值分析方法,研究了工况参数对水润滑径向滑动轴承成膜性能的影响。给出了径向滑动轴承的几何关系,忽略水润滑径向滑动轴承密度与粘度变化,建立数学模型,将数学模型无量纲化后再进行求解及离散,根据离散的控制方程,利用FORTRAN语言进行编程,同时采用高斯-赛德尔迭代法进行迭代,并用ORIGIN软件进行分析。结果表明,随着卷吸速度的增大,偏位角增大,偏心率减小,最小膜厚增大;随着载荷参数的增大,偏位角减小,偏心率增大,最小膜厚减小。该研究对此类摩擦副的润滑设计具有一定的参考意义。     

石墨密封材料润滑膜形成规律及摩擦磨损研究

为了研究石墨密封材料润滑膜形成规律及其摩擦磨损特性,使用MMW-1立式万能摩擦磨损试验机分别对浸渍金属锑、浸渍树脂和人造石墨多组试样进行摩擦磨损试验.研究表明:浸锑石墨密封材料呈现快速成膜、迅速稳定的有膜润滑状态,其摩擦系数在0.08左右;浸树脂石墨密封材料因材料硬度不同而呈现有膜润滑、贫膜润滑和残膜润滑状态,摩擦系数为0.07～0.1;人造石墨表现为无膜润滑,摩擦系数在0.25左右.有膜摩擦耐磨损性能最好,贫膜摩擦耐磨损性能不稳定,无膜摩擦磨损严重.     

水轮发电机镶嵌固体润滑剂轴承的应用研究

根据固体润滑机理设计了水轮发电机镶嵌轴承用固体润滑剂配方，对不同冷却条件下的产品进行摩擦磨损性能试验、台架模拟试验，用扫描电镜(SEM)对摩擦表面形貌进行分析。试验结果表明：以聚四氟乙烯为主体的固体润滑剂在金属表面可形成润滑转移膜；在水轮发电机特殊工况下(高载荷、往复运动)，固体润滑剂中的填料(纤维)在摩擦过程中出现局部取向现象，增加承载能力；当树脂与填料用量相近时，复合材料成型冷却条件对摩擦系数、磨损量的影响不明显；在铜套中镶嵌固体润滑剂可明显降低铜套与钢之间的摩擦系数与磨损量。     

石墨含量对风电机组用铜基摩擦材料摩擦磨损性能的影响

采用粉末冶金技术制备风电机组用的铜基摩擦材料。研究在不同的摩擦速度下,石墨的含量对材料的摩擦磨损性能的影响。结果表明:材料的磨损率随着摩擦速度的增加而增加。随着石墨含量的增加,材料的磨损率增加,由于石墨破坏基体的连续性使得材料的强度降低,从而使材料的磨损率增加。材料的摩擦系数随着石墨含量的增加而降低,这是因为材料摩擦过程中摩擦表面形成具有润滑作用的摩擦膜。石墨含量为10%的材料具有较好的摩擦磨损性能。     

双圆弧谐波减速器共轭啮合区混合润滑分析

为了给轮齿啮合区的加速寿命试验提供理论依据,更好地指导产品优化设计,以某型号谐波减速器为分析对象,基于包络理论求出柔轮与刚轮的齿廓方程,分析了啮合点的曲率半径、卷吸速度以及啮合区受载情况,综合考虑啮合区的宏观几何、真实表面粗糙度等因素,建立了柔轮与刚轮啮合区的混合润滑模型,通过分析润滑区膜厚比、摩擦因数等参数,定量研究了转速和温度对润滑性能的影响.结果表明:转速越高,平均油膜厚度和膜厚比越大,接触载荷比和接触面积比越小,润滑性能越好.当转速高于2 200 r/min时,啮合区由边界润滑变为混合润滑,接触载荷比和接触面积比较50 r/min时减小90%以上,摩擦因数减小一半以上,将转速控制在2 200 r/min以上有利于改善润滑状况;随着啮合区温度的升高,平均油膜厚度和膜厚比逐渐减小,接触载荷比和接触面积比逐渐增大,润滑状况逐渐变差.温度为60℃时,摩擦因数较10℃增加一倍以上,接触载荷比和接触面积比增加一倍以上,需严格控制谐波减速器工作温度在60℃以下.     

ZM6镁合金的摩擦性能研究

以ZM6镁合金为试验材料,利用正交试验方法和方差分析方法研究了粗糙度、转速和载荷对摩擦系数影响的权重顺序以及其对摩擦性能的影响.结果表明:各因素对摩擦系数影响的权重顺序依次为粗糙度、转速、载荷; 转速为30 r/min时,摩擦系数随着载荷的增加而增大,随着粗糙度的增大先减小后增大; 转速为45 r/min时,摩擦系数随着载荷和粗糙度的增大均先减小后增大; 转速为60 r/min时,摩擦系数随着载荷的增加而减小,随着粗糙度的增大先增大后减小; 载荷为35 N时,摩擦系数随着转速的增大先增大后减小; 载荷为50 N时,摩擦系数随着转速的增大而增大; 载荷为65 N时,摩擦系数随着转速的增大逐渐减小.     

三叉杆万向联轴器的点接触润滑特性分析

为了控制滚珠轴承与滑块之间的点摩擦,提高三叉杆滑块式万向联轴器在汽车传动轴系统的工作效率,因此研究三叉杆滑块式万向联轴器在润滑脂情况下的润滑特性。本研究以弹流润滑点接触理论为基础,采用多重网格法对Ostwald方程进行量纲一化,得出量纲一化后的Reynolds方程,然后对Reynolds方程进行差分处理,得出差分处理后的润滑脂油膜厚度公式和载荷公式。研究结果表明:三叉杆滑块式万向联轴器的润滑特性与输入轴频率、载荷、输入输出轴夹角、滚珠半径和压黏系数有关,润滑脂的膜厚和压力随着输入轴频率、输入输出轴夹角和滚珠半径的增大而减小,而随着载荷和压黏系数的增大而增大。本研究为三叉杆滑块式万向联轴器在汽车传动轴系统应用时控制摩擦磨损提供理论依据和技术支持。     

Al2O3陶瓷与铸铁副在空气和蒸馏水润滑下的滑动磨损

在室温、干摩擦(空气)及蒸馏水润滑条件下使用环块磨损试验机进行Al2O3陶瓷和球墨铸铁、灰铸铁及钢配副时的滑动磨损试验.结果表明:蒸馏水润滑下Al2O3及铸铁的磨损体积均小于在干磨擦条件下;在同一润滑条件下,钢的磨损体积大于铸铁磨损体积,球墨铸铁磨损体积最小;陶瓷Al2O3磨损体积在干摩擦时与铸铁配副时比与钢配副时要小得多.对Al2O3磨面进行形貌及能谱分析,发现在干摩擦条件下,Al2O3磨面有大量铸铁或钢的转移物组成的迁移膜,在蒸馏水润滑条件下则没有.分析认为,铸铁中石墨在于摩擦时能起到较明显的固体润滑剂作用,相对地减小了磨损,而在蒸馏水润滑下石墨的润滑作用己大大减弱.     

摩擦副不同表面织构化的润滑减摩性能试验研究

为研究织构位于摩擦副不同表面时的润滑减摩性能,对无表面织构、上试件单表面织构、下试件单表面织构和双表面织构四种不同形式的摩擦副分别在富油和乏油两种润滑条件和50N,100N两种载荷下进行摩擦磨损试验,观察摩擦系数变化规律.试验结果表明:载荷越大,表面织构对摩擦系数的影响越显著;富油条件下,上、下试件单表面织构均能减小摩擦系数,而且上试件单表面织构更加有效;乏油条件下,下试件单表面织构减小而上试件单表面织构增大摩擦系数;双表面织构在不同的润滑条件下均不能减小摩擦系数.     

混杂增强AZ91复合材料的制备及其显微组织和性能

采用挤压铸造方法制备了以AZ91镁合金为基体、Al2O3短纤维(Al2O3f)和石墨颗粒(Grp)混杂为增强体的复合材料。观察了不同复合材料的显微组织,测试了其力学性能,并对其摩擦磨损性能进行了研究。结果表明:用此法制备的镁基复合材料增强相分布均匀,与基体结合紧密。硬度随Grp体积分数的增加而降低,Al2O3f的加入能提高复合材料的硬度。抗拉强度和伸长率都随Grp体积分数的增加而减小。Grp体积分数增加,磨损质量损失和摩擦系数都降低。随着摩擦过程的进行,在试样表面逐渐形成一层黑色连续的润滑膜。     

SF-1材料水润滑艉轴承摩擦性能研究

针对传统船舶艉轴承的应用现状与不足,在SSB-100型船舶艉轴试验机上对SF-1高分子石墨轴承进行水润滑条件下的摩擦性能试验,分析了载荷、线速度和润滑水温变化对摩擦系数的影响规律以及摩擦磨损性能。结果表明,SF-1材料具有优良的自润滑性能,摩擦系数低,承载压力高以及耐磨性好,在船舶行业具有广阔的应用前景。     

有机粘结固体润滑膜研究进展

分析了有机粘结固体润滑膜的减摩耐磨主要机理,详细讨论了环氧与酚醛环氧、聚酰亚胺与聚酰胺酰亚胺、聚苯硫醚和聚酰胺等常用高分子树脂基体固体润滑膜的摩擦学特性及其性能,展望了高分子固体润滑膜的发展趋势和研究方向.     

A comparative study of tribological properties between perfluoro and non-perfluoro alkylsilane self-assembled monolayers(SAMs)

The tribological properties of perfluoro and non-perfluoro alkylsilane molecular films were investigated and compared detailedly. Their surface properties were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle (CA) measurement. A ball-on-disk tribometer was used to study the frictional properties of these alkylsilane monolayers. The experimental results reveal that the alkylsilane molecular films are good candidates to decrease friction and they have good capability to endure rigorous shear forces. Perfluoro alkylsilane molecular films are bonded better with the Si substrate than the simple hydrocarbon ones. The effects of sliding velocity and normal load on friction coefficient are evident and the friction coefficient increases with the increase of the sliding velocity. However, friction coefficient decreases with the increase of normal load initially and then increases, indicating there exists a critical normal load for the load effect. Funded by the National Natural Science Foundation of China (No.50730007 and 50805086), the Foundation of Tsighua Basic Research, and the National Key Basic Research Program of China(No. 2007CB607604)     

钛合金材料防微动磨损涂层性能研究

采用超音速火焰喷涂工艺在TC4钛合金基体材料表面制备碳化铬系耐磨涂层,通过自制微动磨损试验设备测试不同对磨副、不同位移副值试验条件下带涂层的TC4钛合金材料的摩擦因数、磨损量等微动磨损性能,利用SEM、EDS、XRD等分析手段,对比分析微动磨损表面形貌、成分和相组成的差异.结果表明:不同摩擦副和位移副值条件下的摩擦因数...     

Effect of fretting amplitudes on fretting wear behavior of steel wires in coal mines

Given that fretting wear causes failure in steel wires, we carried out tangential fretting wear tests of steel wires on a self-made fretting wear test rig under contact loads of 9 and 29 N and fretting amplitudes ranging from 5 to 180 μm. We observed morphologies of fretted steel wire surfaces on an S-3000N scanning electron microscope in order to analyze fretting wear mecha-nisms. The results show that the fretting regime of steel wires transforms from partial slip regime into mixed fretting regime and gross slip regime with an increase in fretting amplitudes under a given contact load. In partial slip regime, the friction coefficient has a relatively low value. Four stages can be defined in mixed fretting and gross slip regimes. The fretting wear of steel wires in-creases obviously with increases in fretting amplitudes. Fretting scars present a typical morphology of annularity, showing slight damage in partial slip regime. However, wear clearly increases in mixed fretting regime where wear mechanism is a combination of plastic deformation, abrasive wear and oxidative wear. In gross slip regime, more severe degradation is present than in the other regimes. The main fretting wear mechanisms of steel wires are abrasive wear, surface fatigue and friction oxidation.     

AM60B镁合金在滑移区的微动磨损行为研究

研究了AM60B镁合金在滑移区的微动磨损行为。考察了摩擦因数和磨损体积随循环次数、载荷和频率的变化及磨损表面形貌，探讨了其微动磨损机理。结果表明：AM60B镁合金的微动磨损可分为开始阶段、二体接触向三体接触过渡阶段和稳定阶段3个阶段。在不同的阶段，摩擦因数和磨损体积的变化及磨损机制各有特点；此外，磨损体积随着法向载荷的增加而增大，但随着频率的增大而减小。     

Tribological properties of nanostructured n-Al_2O_3/Ni coatings deposited by plasma spraying

1INTRODUCTION Nanostructuredmaterialsareofprimeinterestsincetheyshouldexhibitsuperiorpropertiesin comparisonwithconventionalmaterials(i.e.mi crostructured).Thermalsprayingisregardedasoneofthepossiblemethodstodepositnanostruc turedcoatings.Researchworkshav…     

Tribological Behavior of Nano-ZrO_2 Reinforced PTFE-PPS Composites

Polytetrafluoroethylene(PTFE) is a commonly used seal material for oil-free engine that is well known for its excellent tribological properties. In this work, the nano-ZrO_2 particles were used as the friction modifiers to improve the friction and wear performance of PTFE-PPS composites. The friction and wear characteristics of PTFE/PPS-nano-ZrO_2 composites were investigated by a block-on-ring tester under dry friction sliding condition. The worn surfaces, counterpart transfer films and wear debris were studied by scanning electron microscopy and X-ray photoelectron spectroscopy. It was found that the increase of nanoZrO_2 content could effectively reduce the coefficient of friction and enhance the anti-wear ability of PTFEPPS composites. Especially, the best tribological properties of the composites were obtained when the particle content of nano-ZrO_2 was 10 vol%, the anti-wear performance of composite is 195 times better than that of the unfilled PTFE-PPS composite. Under different conditions, the coefficient of friction of PTFE/PPS-nano-ZrO_2 composites was more affected by the applied load while the wear rate was more affected by the sliding velocity.     

Comparison of tribological properties for graphite coatings used for remanufacturing

To improve the solid lubricity on the worn surface of frictional-pairs, a convenient and simple brush-painting technique was utilized to prepare the solid lubrication graphite coatings. The bonding between the coatings and substrate is good. To examine the influence of the different graphite contents on the tribological properties of the graphite coatings, the comparison experiments were carried out on the ring-on-block friction tester. The tribological results show a change law of saddle-shape between the tribological properties of graphite coatings and graphite content. When the amount of graphite is up to 28 g, the tribological properties of graphite coating are the best. The excellent anti-friction of the graphite coating is associated with the close-packed hexagonal crystal structure of graphite.