The Kinetics of Shear-Induced Boundary Film Formation from Dimethyl Disulfide on Copper

The kinetics of the shear-induced surface-to-bulk transport of methyl thiolate species formed from dimethyl disulfide (DMDS) on a copper surface are explored. It is found that the loss of surface species as a function of the number of rubbing cycles can be modeled by assuming that the adsorbed layer penetrates the subsurface a distance of ~0.7 nm per scan. Adding wear to this model does not improve the fit to the experimental data providing an upper limit for the wear rate of ~0.06 nm/scan. This model is applied to analyzing the depth distribution of sulfur within the subsurface region as a function of the number of rubbing cycles, measured by Auger depth profiling when continually dosing the copper sample with DMDS. It is found that the shape of the experimental depth profile is in agreement with the model developed to analyze the surface-to-bulk transport kinetics of the adsorbed layer. However, the profiles are almost identical for surfaces that have been rubbed 130 and 360 times, so that the surface-to-bulk transport kinetics are self limiting.     

Molecular Dynamics of Thin Lubricant Films on Sol-Gel SiO2 Surfaces for Thin Film Magnetic Disks

Mobility of molecularly thin lubricant film is an important issue in understanding boundary lubrication mechanisms and to develop reliable magnetic disk media. Intra-molecular mobility for a perfluorinated poly ether (PFPE), which is used as a disk lubricant, with two hydroxyl groups on a sol-gel SiO₂ surface, which is used for a protective overcoat for plated magnetic disks, was studied using nuclear magnetic resonance (NMR). Thin film viscosities for molecular segments were derived from a relaxation time. The viscosity for the hydroxyl segment is 1.8 to 11 times as much as that for a bulk lubricant at room temperature, and the viscosity rate increased with increasing temperature. For example, it increased 15 times at 100°C. The viscosities for the segments in a main chain were not different from that of bulk PFPE.

A spin-off calculation for the molecularly thin lubricant film with thin film viscosity, derived from the NMR method, shows that there is no thickness decrease after seven years.     

纳米薄膜轴承薄膜破坏分析

纳米薄膜可以改善滚动轴承的表面质量，以减少振动、降低噪声，减小摩擦、延长轴承寿命。试验证明，含纳米薄膜的滚动轴承疲劳寿命明显高于普通轴承。本文讨论纳米薄膜轴承表面纳米膜的破坏。     

金掺杂氧化铪薄膜的电阻转变性能研究

采用射频磁控溅射法在ITO基底上制备了Hf O2和Hf O2:Au薄膜,并对Cu/Hf O2/ITO和Cu/Hf O2:Au/ITO三明治结构进行了电阻转变性能测试。结果表明:两者均展现出可逆双极电阻转变性能,但Cu/Hf O2:Au/ITO器件的SET电压较小,电压分布更加集中并且性能更稳定。通过对器件双对数I-V曲线拟合分析,发现其电阻转变机制为空间电荷限制电流效应。金的掺入增加了薄膜中的缺陷,提高了基于氧空位的导电通道的均一性,从而优化了器件的电阻转变性能。     

正十六烷基础油中减摩剂和分散剂相互作用的分子动力学模拟

采用分子动力学模拟加入减摩剂单油酸甘油酯(GMO)和分散剂聚异丁烯琥珀酰亚胺-多胺(PIBSA-PAM)的正十六烷基础油在不同压力条件下剪切时的摩擦学特性.构建光滑铁壁面的纳米间隙润滑剂模型,对GMO分子、PIBSA-PAM分子和壁面之间的吸附和团聚行为进行阐释,得出润滑油膜中每种分子的密度分布及剪切过程中的速度分布,...     

光学薄膜的研究

本文概述了当前薄膜光学领域里的一些研究工作,并就具体的研究方向,如:光学薄膜的离子束辅助淀积和离子束溅射、低能离子镀技术,光学薄膜的成核、生长和微结构的模型,薄膜特性的检测和微结构分析等作了论述。     

CVD-Si3N4薄膜工艺及性能研究

以三氯硅烷和氨气作为硅源和氮源，利用低压化学气相沉积工艺（LPCVD）在烧结氮化硅表面制备氮化硅薄膜。考察了工艺参数对沉积速率的影响，并对薄膜的组成、结构及硬度等性能进行了分析。结果表明，当载气为N2或N2＋H2、沉积温度为800℃、NH3／HSiCl3流量比为4时是较佳的工艺条件，此时薄膜沉积速率可达23．4nm／min，其膜层主要由Si-N组成，并含有部分Si-O，硬度为HV2865。     

硬质合金刀具基体沉积低表面粗糙度金刚石薄膜的工艺研究

CVD金刚石薄膜刀具的表面粗糙度是影响刀具切削性能的重要参数。为通过改进CVD沉积工艺减小金刚石薄膜表面粗糙度 ,提出了适当提高碳源浓度和合理控制沉积气压两项新的工艺方法 ,并通过切削试验研究了其对金刚石薄膜刀具耐用度及切削性能的影响     

Modeling Bearing and Shear Forces in Molecularly Thin Lubricants

Under the effects of high shear rate and confinement between solid surfaces, the behavior of a thin lubricant film deviates from that of the bulk, resulting in significant increases of lubricant viscosity and interfacial slip. A semi-empirical model accounting for the breakdown of continuum theory at the nanoscale is proposed—based on film morphology and chemistry from available experimental and molecular dynamics simulation data—to describe lubricant behavior under shear. Viscosity stiffening and interfacial slip models are introduced into the formulations of the normal (bearing) and shear forces acting on a sphere that moves within a thin lubricant film parallel to a rigid plane. The experimentally measured ‘apparent’ viscosity confounding the effects of both stiffening and slip is used to predict the hydrodynamic forces acting on a fully or partially submerged sphere for the purposes of describing lubricant contact in magnetic storage. The proposed sphere-on-flat model forms the basis of a future, dynamic contact with friction model that will account for lubricant contact in the context of molecularly thin lubricated rough surface contact.     

尼古丁印迹聚合物分子识别特性的光谱研究

以尼古丁为模板分子，甲基丙烯酸为功能单体，乙二醇二甲基丙烯酸酯为交联剂，合成尼古丁分子印迹聚合物。采用紫外光谱和1H核磁共振波谱研究了该印迹聚合物的结合位点和识别机理。结果表明，该聚合物中尼古丁与甲基丙烯酸通过协同氢键作用形成1：2型配合物。甲基丙烯酸分子中羧基氢原子是氢键的质子给予体；尼古丁分子吡啶环和四氢吡咯环上的两个氮原子是接受质子的识别位点。该印迹聚合物通过协同氢键作用选择性的识别尼古丁分子。     

薄膜吹塑模芯螺旋槽的数控加工

分析了薄膜吹塑模芯螺旋槽的特点,用通用模具软件进行了设计造型和加工仿真,并在四轴数控加工中心机上生产出模芯,已应用于多层吹塑模具产品中。     

剪切应力影响下近壁微液膜测量技术及波动特性研究

基于尺度分离理论,近壁微液膜波动特性对临界热负荷的产生有至关重要的影响。针对水平管内分层流动近壁微液膜在气流剪切应力作用下的波动特性进行研究,分析声学法,射线法,电学法和光学法等不同检测方法在近壁薄液膜厚度测量上的应用,并比较各种方法的优缺点。最终采用光学法,即利用光谱共焦位移传感器,对不同气、液流速条件下近壁微液膜进行测量,分析剪切夹带对液膜厚度变化的影响规律,获得液膜撕裂的临界条件。研究结果表明：微液膜平均厚度在气流剪切夹带影响下随气速的增大而减小。由于液滴夹带现象影响程度的不同,在不同气、液流速条件下,试验段出口处液膜平均厚度液膜呈现线性或非线性的变化趋势。气流剪切应力增大时,液膜厚度超过临界厚度即发生撕裂现象,液膜撕裂存在随机性,当壁面条件一定时,临界液膜厚度不随气、液流速的变化而变化,但在高气、液流速条件下液膜波动加剧。     

二阶流体非牛顿薄膜润滑

从原理出发，推导出二阶流体的本构方程以及润滑方程，并将二阶流体应用于径向轴承和楔形滑块。     

微电子机械系统中的压电薄膜微马达

本文提出了压电薄膜微马达的工作原理,介绍了该马达的优良性能、结构形式和加工工艺,最后指出了该马达研制的关键技术以及应用前景。     

Modeling Sliding Contact of Rough Surfaces with Molecularly Thin Lubricants

The sliding contact between two rough surfaces in the presence of a molecularly thin lubricant layer is investigated. Under very high shear rates, the lubricant is treated as a semi-solid layer with normal and lateral shear-dependent stiffness components obtained from experimental data. The adhesive force in the presence of lubricant is also adapted from the Sub-boundary lubrication model and improved to account for variation in surface energy with penetration into the lubricant layer. A model is then proposed, based on the Improved sub-boundary lubrication model, which accounts for lubricant contact and adhesion and its validity is discussed. The model is in good agreement with published experimental measurements of friction in the presence of molecularly thin lubricant layers and suggests that a molecularly thin lubricant bearing could be successfully used to reduce solid substrate damage at the interface.     

Theoretical Study on the Interferometry of Thin EHL Film Measurement

Interferometry has been widely utilized in elastohydrodynamic lubrication (EHL) film measurement since the 1960s. In-depth optical analyses are required to get more fundamentals of optical EHL film tests. In this paper, a stratified-layer model of optical EHL contact is numerically analyzed by the multi-beam interference approach. It is revealed that the high reflectance of the beam-splitter and the steel interface generate a deviation of the intensity profile from the two-beam interference. Previous experimental results about fringe contrast are reproduced, and the determination of the beam-splitter layer is theoretically clarified. Furthermore, some characteristics of spectrometry for ultra-thin film measurement are studied, and the dependence of the interference spectrum on the spacer layer thickness is displayed. The measurement simulation has theoretically confirmed the constant initial phase change assumed in practical measurement. It is theoretically demonstrated that in the spectrometry approach, TiO₂ layer can generate spectrum with high finesse and may be used in the future application. The theoretical results in this paper are correlated with previous experimental practices, and the optical EHL technique can therefore be much better theoretically understood.     

The Effect of the Electric Double Layer on a Very Thin Water Lubricating Film

This paper discusses the effect of the electric double layer on a very thin water lubricating film with and without consideration of the elastic deformation of the opposing surfaces. A modified Reynolds equation that considers the electric double layer is used in a numerical analysis. The effect of zeta potential on the film thickness and pressure is numerically calculated. For both hydrodynamic and elastohydrodynamic cases, the electric double layer significantly increases the lubricating film thickness. The pressure is also marginally increased, as illustrated in the hydrodynamic analysis. However, the effect on pressure is almost unnoticeable in the elastohydrodynamic analysis. Overall, the electric-double-layer effect is only significant for a water-film thickness of less than approximately 100 nanometers.     

薄膜应力的测定

本文介绍一种利用长焦距显微镜观察玻璃薄片由镀膜淀积引起的形变来测量薄膜应力的方法。对于该实验装置的几个主要结构部份、测量的原理及方法和提高测量精度所采取的主要措施作了较详细的描述。最后给出了在不同真空度和蒸发速率时硫化锌膜、氟化镁膜及硫化锌—氟化镁多层膜的应力分别随薄膜几何厚度而变化的实验结果。     

钽铝薄膜中功率衰减器的设计

介绍了一种用于微波电路的中功率薄膜衰减器的设计与制作。该衰减器是由铝原子含量为50％的Ta／Al合金薄膜制成。测试结果表明其性能优良。     

铁电薄膜的制备方法

介绍了制备铁电薄膜的几种不同种类的方法.LSMCD技术是一种新型的制备铁电薄膜的技术.采用超声雾化产生微米级或亚微米级尺寸的气雾,再用载气将气雾引入沉积室内,沉积在基片上.重复此过程直至膜厚达到所需厚度.