钢-铜磨合期磨粒分形行为的研究

在环-端面磨损试验机上,用45~#钢-铜摩擦副进行浸油磨损试验,采用由光学显微镜、摄像头、计算机数据采集装置组成的磨粒分析测试系统考察不同磨损阶段产生的磨粒,并求出多种磨粒表征参数。分析结果表明:磨损过程中产生的磨粒,其轮廓具有分形特征;磨粒分形维数的分布呈正态分布;磨粒分形维数相对于其它表征参数而言,和摩擦力相关性更大。因此,对磨粒分形维数的考察有助于了解磨损状态的转变。     

基于Matlab的浸锑石墨密封材料的分形特征研究

针对电厂用的2种浸锑和1种不浸锑的磨煤机用石墨密环材料,利用Matlab编写的分形维数计算程序计算其分形维数,并进行摩擦磨损实验.结果表明:未浸锑材料的相对磨损率约为浸锑的10～30倍,摩擦因素约为2倍;浸锑石墨材料的分形维数(约1.5～1.7)小于不浸锑的(约1.8);摩擦因数随着分形维的增加而增大,磨损量亦随着分形维数的增加而增大.     

表面纳米化中碳钢磨合磨损性能研究

为研究表面纳米化中碳钢在润滑条件下的磨合性能,用环-盘摩擦磨损试验机进行磨合磨损试验.分析在不同载荷下摩擦系数和摩擦振动信号多重分形谱参数的变化,通过磨损表面形貌探讨表面纳米化影响中碳钢磨损行为的原因.结果表明:在低、中负荷作用下,表面纳米化处理的中碳钢摩擦系数和振动信号多重分形谱参数较未处理的有所降低,其较高的表面活性可更好地吸附润滑油以形成油膜.因此,在低、中负荷条件下,表面纳米化可提高中碳钢磨合磨损性能.     

半金属摩擦材料的摩擦磨损性能及磨屑形貌

采用D－MS定速式摩擦试验机，测定了3种金属纤维（钢纤维，黄铜纤维和紫铜纤维）增强的半金属摩擦材料与灰铸铁在不同温度下滑动摩擦的摩擦磨损性能，并收集磨屑，借助SEM扫描电子显微镜，观察，分析磨屑的形貌，研究材料磨损的内在机制。研究结果表明：紫铜纤维增强的磨擦材料与灰铸铁间的摩擦因数最稳定，磨损率最低；低温时，3种材料的磨屑均比较细小，在少数大颗粒的表面可以观察较深的划痕，有的带有明显的裂纹，说明该磨损主要由犁沟及微切削作用引起；高温时，磨屑多呈较大的块状或薄片状，这是粘结剂的高温分解和摩擦表面膜的热裂分解所致；对于铜纤维（黄铜或紫铜），在摩擦过程中还会发生铜在对偶表面的涂抹现象，这也是影响其摩擦磨损性能的一个重要因素。     

大口径弹带材料黄铜的磨损机理研究

为开发适用于高膛压发射条件的新型弹带材料,研究传统黄铜弹带材料的磨损机理。采用HSR-2M往复式摩擦实验机测试黄铜的摩擦磨损性能,并结合OM、SEM/EDS分析磨损黄铜的形貌和成分。结果表明,在30N载荷下,滑动速度按照200r/min、400r/min、600r/min次序增加时,黄铜的摩擦系数先增大后减小,磨损量在滑动速度为600r/min时急剧增大。滑动速度由200r/min提高到600r/min时,由于摩擦表面温度达到黄铜的熔点,黄铜的磨损机制由磨粒磨损转变为熔化磨损。     

介质分子中的羟基活性基团在选择性转移中的作用

研究摩擦介质分子中羟基活性基团数目对选择性转移摩擦学特性的影响。对黄铜摩擦表面膜的结构成份进行化学电子能谱分析及红外吸收光谱分析。建立选择性转移作用机理模型，找出介质分子中羟基数目与摩擦学特性及黄铜表面膜强度间的对应关系，得出了有价值的结论。     

压铸ZL101A铝合金摩擦磨损性能及机理的研究

以汽车发动机缸体用的ZL101A铝合金作为研究对象,开展了在SiN、GCr15两种摩擦副条件下摩擦载荷对ZL101A铝合金磨损性能及磨损机理的研究.试验结果表明:ZL101A铝合金在SiN和GCr15两类摩擦副中,随着摩擦载荷由2N增加至4N时,平均摩擦系数和磨损量均先增加后降低;在不同摩擦载荷下,SiN摩擦副的试样摩擦磨损平均摩擦系数均低于GCr15摩擦副;摩擦磨损过程发生了剥层磨损、磨粒磨损、黏着磨损以及氧化磨损多种磨损机制,只是在不同的试验条件下磨损机制的作用程度不同;在SiN摩擦副中磨屑的黏着、碾压现象比GCr15摩擦副中更加明显,以至于SiN摩擦副中摩擦表明的氧化现象比GCr15摩擦副中更加明显.     

YT类硬质合金刀具在磨损状态下的分形结构研究

通过对ＹＴ类硬质合金刀具在磨损状态下的分形结构研究，对刀具磨损的判别提出了一种新的方法。     

碳化钨涂层的摩擦磨损行为研究进展

磨擦磨损与腐蚀是各种机械装备与电站设备中金属工件失效的主要形式,它会导致能源和材料消耗增加,由此所造成的经济损失是巨大的,WC涂层是一种减少工件磨损的有效保护涂层.通过对碳化物涂层的摩擦磨损行为、涂层结构、涂层磨损机理等进行较系统的分析,阐述了国内外碳化物涂层的摩擦磨损行为研究进展,讨论了耐磨涂层磨损的微观机制,以及制备工艺、WC含量及其它因素对涂层耐磨性能的影响规律,指出了WC涂层摩擦磨损研究的发展方向.     

载荷对Kevlar/PTFE纤维混杂织物摩擦学性能的影响

采用电子小样织机机织Kevlar/PTFE纤维混杂织物,借助于MMU-5G端面摩擦磨损试验机,激光扫描共聚焦显微镜（CLSM）,考察了Kevlar/PTFE纤维混杂织物在高速、干摩擦时不同载荷下的摩擦磨损性能。结果表明,在转速为300 r/min下,载荷越高,稳态摩擦系数值越低,随着载荷的不断增加,稳态摩擦系数下降趋势变缓;织物磨损深度随载荷增加而增加,但磨损率反而降低,织物的摩擦磨损与织物结构有关,磨损方式主要为磨粒磨损,以及PTFE在法向载荷挤压和摩擦剪切作用下发生塑性变形。     

Fractal identification of wear debris group in sliding wear process

Fractal geometry was used to describe the distribution characteristics of wear debris group collected from pin-on-disc wear tester under dry friction conditions, and experimental study and theoretical analysis were made for the distribution features of wear debris group. It was found that the wear debris size distribution conforms to the fractal distribution law. Two numerical parameters, fractal dimension D and scale coefficient C,were defined with their geometric and tribological meanings and calculating methods given. It was discovered that these two parameters can be used to describe the variation law of wear status, which provide the basis for diagnosis and prognosis of tribological systems.     

磨屑破碎及分布的多重分形模拟

基于多重分行理论和磨屑尺寸分布的统计自相似性，建立了磨屑破碎过程的多重分形模型，以数论和矩阵2种方式对磨屑破碎过程和分布进行了论述，并利用多重分形模型对具体工况下磨屑破碎过程和分布进行了模拟，并将模拟结果与实验统计结果进行了对比分析．结果表明，该模型能够较精确的描述磨屑的破碎过程和分布，具有静态（磨屑分布）和动态（磨屑破碎过程）二重性；根据多重分形分形维数表达式所求出的分形维数具有惟一性，体现了多重分形表征磨屑破碎过程和分布的惟一性；该模型对磨屑破碎过程和分布的描述和预测基本不受测量仪器分辨率和取样长度的影响，因而比传统基于统计分析的模型更为合理和有效．     

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.     

稀土镁合金的摩擦磨损性能

采用MMS-2A型环块式摩擦磨损试验机对稀土镁合金GW103K进行了摩擦磨损试验.试验结果表明:GW103K体积磨损量随着磨损时间和外载荷的增大而增大,当磨损时间超过30min,外载荷超过400N时,体积磨损量增大明显;摩擦因数在0.26~0.28之间变化.对摩擦副环块,转速与体积磨损量成正比,与摩擦因数成反比.     

Comparison of the Wear Behavior of UHMWPE Lubricated by Human Plasma and Brine

The effect of plasma and brine lubricants on the friction and wear behavior of UHMWPE were studied by using the geometry of a Si3N4 ball sliding on a UHMWPE disc under patterns of uni-directional reciprocation and bi-directional sliding motions. The worn surface and wear particles produced in these two lubricants were analyzed. Sliding motion pattern affected the friction coefficients lubricated with plasma, while seldom affected that lubricated with brine. UHMWPE lubricated with plasma showed about half of the wear rate of that lubricated with brine. The two rates were 0.75 pg/m and 2.19 pg/m for the two motion patterns, respectively. However, wear particles generated in plasma included a greater amount of small particles, compared to that in brine. In uni-directional reciprocation, the main wear mechanism is ploughing both in plasma and in brine. In bi-directional sliding modes, the significant characteristic is ripples on the worn surface in plasma, while there are oriented fibers on the worn surface in brine.     

Microstructural characterization and mechanical property of Fly Ash/Al-25Mg composites

Fly ash/Al-Mg composites are fabricated by powder metallurgical method. The morphology and structure of fly ash/A l-Mg composites are characterized by scanning electron microscope （SEM） and X-ray diffraction, respectively. The influences of different fly ash content on the friction and wear behavior of the composites are investigated at a constant sliding velocity of 400 r/min and the worn mechanism of composites is discussed. The results indicate that the friction coefficient is steadily lower than that of Al alloy matrix at the lower fly ash content and loads. For the fly ash/Al-Mg composites, the wear mechanism is characterized as abrasive wear and adhesive wear under small normal load and at low fly ash content, and it is characterized as delamination wear and abrasive wear transferred onto the counterpart under high normal load and at high fly ash content.     

QPQ表面疏松层纯磨损试验研究

在M-2000型磨损试验机上进行纯磨损试验,研究了QPQ表面改性层在浸油擦干后的滑动干摩擦磨损过程。根据磨损曲线和摩擦系数的变化,发现其摩擦磨损过程存在一个干摩擦向边界摩擦过渡的亚稳定阶段,稳定阶段的磨损率和摩擦系数仅为未浸油干摩擦磨损试验时的三分之一。利用SEM分析各阶段磨损表面形貌,QPQ表面改性层磨合阶段的主要磨损机理为黏着磨损,亚稳定和稳定阶段对应的磨损机理为显微切削和划伤。试验结果表明,QPQ表面改性层外表面存在一定程度的疏松层可以储存润滑油,降低摩擦因数,避免或减轻了黏着磨损及磨粒磨损。