Structure and microtribological characteristics of laser-arc deposited TiB2 thin film

TiB2 thin film was deposited by laser-arc deposition method on the surface of single crystalline silicon. The morphology, composition, structure and microtribological properties of the film were studied by using XPS, XRD and atomic force/friction force microscope (AFM/FFM). The results show that TiB2 (100) preferred growth on the Si(100)substrate, TiB2(001) preferred growth on the Si(111) substrate. The TiB2 thin film was composed of TiB2 and a small amount of TiO2. The friction coefficient of TiB2 film on substrates Si (100) and Si(111) in microtribological process were 0.087 and 0.073,respectively. TiB2 thin film displayed distinct ability of anti-scratch and wear-resistance.     

MEMS动平板的切向静电阻力

由于微机械的表面积与体积之比远大于宏机械,所以微机械中的表面阻力难以忽略,为了改善MEMS器件的性能和可靠性,必须对其影响进行研究.基于能量守衡法,本文建立了光滑平板和正方形、四棱锥两种微凸体粗糙表面平板的切向静电阻力模型,讨论了微小尺度、表面形貌、外加电压以及因流片制造工艺而产生的微凸体、凹坑或孔对两个相对运动的带电平板间的切向静电阻力的影响.分析表明：当平板宽度与两平板之间的距离之比、表面形貌因数和外加电压增大时,切向静电阻力也将随之增加;表面形貌因数则与微凸体在平板的总投影面积与平板面积之比成正比,随相对表面粗糙度增加而非线性增加.     

Effect of humidity and temperature on nano/microtribolgical properties of perfluorinated carboxylic acid and hydrogenated carboxylic acid self‐assembled monolayers deposited on aluminum‐coated silicon substrate

Two series of perfluorinated carboxylic acid (FC) and hydrogenated carboxylic acid (HC) self‐assembled monolayer (SAM) films were prepared on aluminum surfaces separately by chemical vapor deposition. The formation, structure and morphology of these films were characterized by measuring contact angle with ellipsometric method, x‐ray photoelectron spectrometry, and atomic force microscopy, respectively. FC and HC SAMs with long chains formed more densely packed films than those with short chains did. The comparative micro/nanoscale friction and adhesive properties of FC and HC SAMs, with various chain lengths on aluminum‐coated silicon substrate, were investigated. The influence of environmental conditions, such as relative humidity (RH) and temperature, on the friction and adhesion behavior was studied. Micro/nanotribological properties of the films were greatly influenced by their backbones and terminal groups. FC SAMs with long chain exhibited adhesion‐resistance, friction reduction, and environmental independence. Copyright © 2009 John Wiley & Sons, Ltd.     

微观摩擦学研究进展

早在十九世纪中叶就有人试图从原子、分子水平上揭示摩擦过程的本质，然而直到原子力显微镜和摩擦力显微镜问世之后的本世纪八十年代，学术界才明确提出了微观摩擦学这个概念。为了推动微观摩擦学的发展，对微观摩擦学的研究方法及其最新研究进展作了综合介绍与评述。微观摩擦学在基础研究方面首先是从边界润滑之研究提出的，而在应用方面则是从磁头－盘之润滑提出的；在研究方法上主要是原子力显微镜、ＬＢ膜技术、表面力装置、石英晶体微量天平、红外、电子能谱和计算机分子动力学模拟等。目前，微观摩擦学主要应用于高密度磁纪录介质的摩擦学研究，同时还应用于微型机械和大规模集成电路的制造，以及微观摩擦、粘着与磨损行为的基础研究等方面，除此以外，还简明地指出了今后微观摩擦学研究应当重视的若干问题。