金属表面多孔膜的保护作用与介质组分的关系

研究了铝阳极氧化多孔膜层界面电性能与溶液介质组分的关系。多孔膜在介质中存在一等电点ＰｈＩＥＰ,当溶液ＰＨ〈ＰＨＩＥＰ时,膜荷正电具有阴离子选择性：ＰＨ〉ＰＨＩＥＰ时,膜荷负电具有阳离子选择性。介质中的一些组分可通过与膜孔表面的相互作用改变膜的ＰＨＩＥＰ,从而发迹膜的荷遇性能手     

用XPS和AES研究锌表面彩色防腐蚀膜

用阴极极化法从钼酸盐和磷酸盐的混合溶液中获得了锌表面彩色转化膜。此膜具有良好的防腐蚀和装饰效果，盐雾试验结果表明，金黄色膜耐蚀性最佳。ＸＰＳ和ＡＥＳ分析结果表明，该膜厚厚度约为７５ｎｍ；膜表面钼以Ｍｏ（ＶＩ）状态存在，而在膜内则以Ｍｏ（ＶＩ）和Ｍｏ（ＩＶ）共存，从ＡＥＳ深度分布曲纡的组成恒定区求得各组成元素的相对原子百分浓度为：Ｏ ５６．９％，Ｍｏ２６．８％，Ｐ １１．０％，Ｚｎ５．３％     

高效液膜法分离富集微量稀土与测定

应用高效液膜法分离富集样品中微量稀土总量（ΣＲＥ）。研究了表面活性剂（Ｎ２０５）、流动载体（Ｐ２０４）、膜的增强剂液体石蜡、膜溶剂（煤油）和内相解吸剂（ＨＣｌ溶液）等对液膜分离富集微量稀土总量的影响。确立了Ｎ２０５－Ｐ２０４－液相石蜡－煤油－ＨＣｌ溶液体系的最佳组成和最适宜的实验条件。富集后的溶液，用５－Ｂｒ－ＰＡＤＡＰ分光光度法测定ΣＲＥ。本法富集微量ΣＲＥ，富集倍数为１３倍以上，回收率为９９．     

铁基体等离子体增强磁控溅射离子镀Ti－TiN涂层的组织结构

利用等离子体增强磁控溅射离子镀（ＰＥＭＳＩＰ），先在铁基体上镀一层很薄的钛中间层，继之沉积ＴｉＮ。对膜层进行俄歇电子能谱（ＡＥＳ）分析和透射电镜（ＴＥＭ）分析。结果表明，膜与基体之间有厚约５０ｎｍ的过渡层；膜基界面处有ＦｅＴｉ相；中间层与后继膜交接处Ｔｉ２Ｎ与α－Ｔｉ有取向关系。     

醋酸钾型除冰液薄液膜厚度对飞机用4130钢腐蚀行为的影响

搭建了薄液膜腐蚀试验装置,使用膨体聚四氟乙烯(E-PTFE)防水透气膜准确控制了薄液膜厚度。利用电化学方法研究了质量分数为5%的醋酸钾型除冰液薄液膜厚度对飞机用4130基材钢腐蚀行为的影响。结果表明:该体系腐蚀过程主要受阴极氧扩散控制,薄液膜下腐蚀产物的溶解与扩散过程对腐蚀速率有较大影响;不同液膜厚度下腐蚀体系的阻抗谱均只有一个时间常数,且溶液电阻随液膜厚度增大而减小。当液膜厚度很薄(30μm左右)时,腐蚀速率很低;随液膜变厚,腐蚀速率先缓慢升高,然后迅速上升;在液膜厚度200μm左右达到极值,然后快速下降;当膜厚进一步增大,接近全浸状态,腐蚀速率又逐渐升高,并趋于稳定。     

意大利STP PRESSE公司压铸机

意大利ＳＴＰ　ＰＲＥＳＳＥ公司压铸机瑞源国际公司ＳＴＰ公司是一家有着２０多年历史的公司，最初为一德国著名压铸机厂商提供设计，同时也自行制造并销售压铸机。ＳＴＰ自行制造及其为该德国厂家所设计、制造的设备，销售到德、意、法、西等国，特别是宝马、大众，奔驰...     

镁合金磷酸盐-高锰酸盐化学转化处理工艺研究

在镁合金表面化学转化处理中，利用正交试验法进行试验，根据磷酸盐-高锰酸盐处理液中组分：KMnO4，K2HPO4，H3PO4(调节pH值)采用四因素，三水平的L9(3^4)正交设计试验，通过分析和计算所得转化膜层厚度和膜厚附着力，知道处理液中H3PO4(pH值)为最重要因素，K2HPO4的重要性次之，KMnO4最弱，并得到各因素最优水平。从而得到磷酸盐-高锰酸盐的最优配方及工艺。通过用该配方所得膜进行盐雾试验结果表明：其耐蚀性与铬酸盐处理液转化膜耐蚀性相同。     

二甲苯不饱和聚酯树脂在30%硝酸中的腐蚀行为

通过失重及表面腐蚀层厚度的测定以及红外吸收光谱（ＦＴ－ＩＲ）、扫描电镜（ＳＥＭ）等分析手段研究了二甲苯不饱和聚酯树脂（ＳＵＰＲ）在３０％硝酸溶液中的腐蚀行为，提出了材料耐该介质腐蚀的机理。结果表明，失重和表面腐蚀层厚度经一定时间浸泡后趋于稳定，不同温度下达到的稳定失重和腐蚀层厚度值不同。腐蚀机理为：浸泡过程中试样表面发生了物理吸附及化学反应，形成了一层淡黄色的特，其厚度与温度有关。该层物质阻止了硝     

飞机起落架镀镉4130钢在甲酸钾溶液薄液膜下腐蚀电化学行为研究

采用自制薄液膜腐蚀试验装置,研究了飞机起落架镀镉AISI 4130钢在低温除冰液(主要成分甲酸钾)薄液膜下的腐蚀电化学行为。结果表明:镀镉4130钢在甲酸钾溶液中的腐蚀过程主要受氧扩散控制,薄液膜下腐蚀产物沉积对腐蚀过程产生较大影响。液膜较厚(≥240μm)时,液膜厚度变化对阴极极限扩散电流密度和溶液电阻影响不大;液膜较薄时,阴极极限扩散电流密度和溶液电阻随液膜厚度减小而增大。在相同液膜厚度下,镀镉4130钢腐蚀电位随溶液浓度增大而降低。在低浓度甲酸钾溶液中,镀镉4130钢腐蚀速率较低,腐蚀电位和腐蚀速率受液膜厚度影响不大。在高浓度甲酸钾溶液中,镀镉4130钢腐蚀电位随液膜厚度减小而正移;薄液膜下腐蚀速率明显高于全浸,且随液膜厚度减小先增大后减小,在液膜厚度约为150μm时出现极大值。     

PDM与MRP—Ⅱ的集成方法研究

通过对企业ＰＤＭ实施情况的具体分析,以ＥＤＳ公司的ＩＭＡＮ产品数据管理软件和美国ＱＡＤ公司的ＭＦＧ／ＰＲＯ系统ＭＲＰ－ＩＩ软件为平台,提出ＰＤＭ与ＭＲＰ－Ⅱ的集成模型。     

A numerical simulation of the thickness of molten mold flux film in continuous casting

The lubricative quality of the liquid flux film formed between a solidified shell and a mold in continuous casting is investigated in this study. Specifically, the effects of the thickness of the liquid flux film and the difference in the thickness between the top and the bottom of the film on the pressure force involved in compensating the ferrous static pressure of cast steel are investigated using a numerical simulation of the fluid flow in the film. The experimentally observed relationship between the operational conditions and the mold flux consumption can be explained using calculated results. The analysis also shows that the shape of the flux film is not uniquely determined by the force balance between the static pressure of the cast steel and the internal pressure of the film.     

A 3D simulation of two-phase flow in an effervescent atomizer for suspension plasma spray

In the suspension spray of nanoparticles, where the attempt is to reach nano-scaled uniform coatings, there is a vital demand to produce a controllable and non-pulsating spray. Effervescent atomizers, in which a gas is bubbled into the bulk of liquid through an aerator, have shown to be a technological alternative to the conventional atomizers when liquid atomization with various concentrations of nano-particles is required. Thus, understanding the behavior of gas and liquid flow through the nozzle is crucial to predict the condition of resultant spray. The two-phase flow inside an effervescent atomizer is numerically investigated. Using an incompressible Eulerian/Eulerian approach, the three-dimensional structure of two-phase flow inside an aerated-liquid injector is modeled. The behaviour of liquid film carrying nano-particles in the discharge passage is studied using different Gas to Liquid mass flow Ratios (GLR), ranging from 0.08% to 1.25%. These numerical results are compared with the experimental data available in literature. The effect of nano-sized solid particles concentration on the liquid film thickness at the exit of the atomizer is studied through the change in liquid bulk density and viscosity. The results show that the atomizing gas-to-liquid mass flow ratio (GLR) does play a key role on the flow behaviour inside the atomizer. At low GLRs of 0.15%, the thickness of the liquid film decreases rapidly and as GLR increases to 1.25% the liquid film thickness dependency on GLR reduces. The results also show that there is no significant effect of particle concentrations, varying within the range of Newtonian fluid, on the liquid film thickness. This feature makes effervescent atomizers a technology choice for controllable suspension thermal spray processes.     

An approach to predict the solid film thickness possibly yielded from an alumina sol-gel liquid film

The Landau-Levich-Derjaguin (LLD) equation is widely used to predict the thickness of wet layer deposited on substrate by dip-coating. But it cannot effectively predict the solid film thickness yielded from the sol-gel liquid layer. Considering the solid content, the amount of solution sticking to the surface of substrate and the density of the sol-gel derived solids materials are the main factors determining the solid film thickness, a new approach capable of directly predicting what an oxide film thickness of a liquid layer on the substrate could yield without really sintering at high temperature was developed. It was found that the predicted and measured thicknesses for both compact and porous Al₂O₃ films were in good accordance. The approach uses very common testing techniques and does not concern the aspects such as solution composition, Newtonian or non-Newtonian fluid, withdrawal speed, viscosity, and liquid-vapor surface tension, etc. So the method is much timesaving and economical, and will be a good supplement for thickness determination techniques, especially under some circumstances where use of SEM, XRR, ellipsometer analyses are limited.     

Suppression of the emeraldine base-to-emeraldine salt transition in ultra-thin films of polyaniline

Electronic absorption spectra of thin films of polyaniline (emeraldine base (EB) and emeraldine salt (ES)) prepared by adsorption at the solid/liquid interface and by casting from dimethylformamid and dimethyl sulfoxide solutions were investigated. Prepared by the same technique and using the same solution, the films however demonstrated divergence in their absorption spectra, depending on the film thickness. The benzenoid-to-quinoid excitonic transition in the EB was blue shifted as the film thickness was decreased. In films exposed to equal levels of acid, thicker films showed more pronounced spectral features of the ES. Spontaneous suppression of the protonation features was found in spectra of adsorbed films of ES as compared to those of a solution from which the film was adsorbed. Also, the protonation features in cast films of ES were weakened as the film thickness was decreased. Possible mechanisms responsible for this phenomenon are discussed.     

考虑涡动工况的螺旋槽液膜密封性能分析

为进一步探索液膜密封性能影响机制，以上游泵送螺旋槽液膜密封为研究对象，基于满足质量守恒的Schnerr-Sauer空化模型，建立密封环涡动模型并基于圆形涡动轨迹，探讨了不同操作工况如压差、转速和膜厚时，涡动方向对密封性能和液膜空化影响。结果表明：正向涡动在变压差和变转速时均可提升液膜承载能力但加剧了泄漏量，反向涡动虽减小泄漏量但较大幅度降低液膜承载能力，不利于密封稳定性；变膜厚时，反向涡动显著降低液膜承载能力，而较大膜厚时正向涡动提升液膜承载能力相对较小；正向涡动有效促生液膜空化，而反向涡动在变压差时有助于抑制液膜空化但低速时对其无影响，并且受膜厚影响较小     

Numerical modelling and experimental investigation of diffusion brazing SS304/BNi-2/SS304 joint

Abstract

The kinetics of dissolution and isothermal solidification at the bonding temperature during diffusion brazing SS304/BNi-2/SS304 has been studied through a combination of analytical modelling and experimental investigations. The modelling is based on the diffusion theory and the consideration of transient motion of liquid/solid interface. A set of coupled finite differential equations has been programmed to track the motion of liquid/solid interface during the isothermal solidification of liquid filler. Four parameters can be mathematically determined from the analytical modelling including the evolution of solute concentration profile, the maximum diffusion distance, and the maximum liquid thickness as well as the time to complete the isothermal solidification. These analyses are helpful to understanding the joining mechanism during diffusion brazing. The temperature dependent diffusion coefficient used in the modelling is derived together with the experimental data from brazing the wedge shaped joint specimen of SS304/BNi-2/SS304. The effects of bonding temperature and initial joint thickness on the joining process have also been investigated.     

离子液体添加剂对润滑剂摩擦和润滑性能的影响

目的研究离子液体作添加剂时对基础润滑剂成膜能力和摩擦磨损性能的影响。方法选取聚α烯烃(PAO8)和锂基脂作为基础润滑剂,用季膦盐油酸离子液体作为添加剂,用UMT-3型多功能摩擦磨损试验机(UMT)进行实验,并对试验后的试样表面进行SEM分析。同时用光干涉点接触润滑油膜厚度测量装置测量其膜厚,通过对比基础润滑剂与添加离子液体后的摩擦系数、膜厚和磨斑,评价离子液体添加剂对基础润滑剂摩擦润滑性能的影响。结果相比于基础油和基础脂,离子液体作添加剂可以有效地降低摩擦磨损。含有离子液体添加剂的润滑剂有更高的油膜厚度,在高载荷工况下更明显。添加离子液体可以有效减轻基础油的乏油程度。结论离子液体添加剂可以有效减小摩擦磨损,提高润滑性能。     

固/液界面润湿性对线接触油膜润滑的影响

目的 优化表征固/液界面的表征参数。方法 应用AF和FAS修饰柱面滑块以获得不同润湿性的表面，并测量PEG200、150N和PAO6三种润滑油在AF、FAS和SiO2表面上的接触角、接触角滞后以及三种表面的表面自由能。通过对线接触润滑油膜厚的测量，评价固/液界面润湿性与油膜厚度的关联性。结果 润滑油为PEG200或150N时，在SiO2/SiO2接触副产生的油膜厚度高于SiO2/FAS接触副，而且接触角越小，油膜厚度越大；接触角滞后越大，油膜厚度越大。PEG200、150N和PAO6润滑油分别在SiO2/SiO2和SiO2/AF同一接触副时，呈现出几乎相同的油膜厚度。此时，接触角滞后与油膜厚度的关联性优于接触角。此外，润滑油在AF表面测得的接触角最大且接触角滞后最小，但产生的油膜厚度最大，该现象可以归因于油膜承载力/厚度与界面强度的非单调性。结论 在线接触流体动压润滑条件下，固/液界面的润湿性能够影响油膜厚度。界面表征参数接触角和接触角滞后，与油膜厚度的关联性都存在一定的局限性，但相对而言，接触角滞后的范围更大。AF界面特性与油膜厚度的关系，证明了疏油表面可以具有较好的成膜能力。     

几种Al合金阳极氧化膜的孔蚀行为

用电化学极化和SEM分析等方法研究了工业纯铝L2，硬铝LY12和超硬铝LC4 3种Al合金的阳极氧化膜在NaCl溶液中的孔蚀行为.3种合金氧化膜在1 mol/L的中性、酸性、碱性NaCl溶液中均发生孔蚀，其阳极极化电流呈台阶式上升.当阳极氧化膜厚度增大时，L2的氧化膜耐孔蚀性能提高，LY12和LC4的氧化膜耐蚀性则没有明显改善.L2的阳极氧化膜上小孔贯穿氧化膜后，优先在Al基体中发展，形成外形规则、内部深 而大的小孔；LY12和LC4的阳极氧化膜上小孔则有膜中发展倾向，形成大而浅的小孔.氧化膜中的合金元素对腐蚀行为有重要影响.     

固液界面对流体动压润滑膜厚的影响

目的研究固液界面对流体动压润滑油膜厚度的影响。方法在面接触润滑油膜光学测量装置中,旋转的光学玻璃圆盘和静止的微型滑块平面构成面接触摩擦副。实验选取PAO6和80%甘油水溶液作为润滑剂,而滑块使用的表面材料为钢和二氧化硅两种。实验中分别利用同种润滑液体与不同滑块表面材料组合,以及不同润滑液体与同种滑块表面材料组合成不同界面组。针对不同界面组进行不同条件下的膜厚-速度关系曲线的测量。各界面的亲和性通过液体对固体的接触角评价。结果 PAO6/钢界面与PAO6/SiO_2界面产生的膜厚-速度曲线无明显差别,并与经典润滑理论计算值保持一致。而PAO6对钢表面和二氧化硅表面的接触角分别为17.5°和21.9°,两界面的亲和性差别不大。当界面组内各界面亲和性差别较大时,对应的膜厚表现出差别。亲和性较弱,或对应液体在固体的接触角较大时,膜厚相对较低。对于文中实验条件,界面效应随载荷的增加表现明显。初步分析表明,载荷的增加会加大摩擦副出口处油膜的剪切应变率,诱发滑移,从而使得界面效应明显。结论在流体动压薄膜润滑条件下,固液界面亲和性可以对膜厚产生明显的影响。