电化学制备多孔硅的工艺对其形貌的影响

采用电化学腐蚀方法,将不同比例的乙醇和质量分数为40%的氢氟酸混合,并以此混合液为腐蚀液,在光照条件下,制备了N型轻掺杂的多孔硅。讨论了不同电化学腐蚀条件对多孔硅结构的影响。研究表明,电流密度、腐蚀时间和氢氟酸质量分数越大时,制备的多孔硅越深,孔径也越大,当以上三者数值过大时会导致多孔硅机械强度急速减弱。由表面形貌可知,当多孔层孔径小于500nm时其机械强度良好,当孔径超过这一阈值尤其是大于800nm时,多孔层骨架则极易断裂。     

脉冲电化学加工表面形貌与摩擦磨损

通过对脉冲电化学、电火花以及机械加工形成的不同表面形貌的对比，来分析加工表面形貌与摩擦磨损之间的影响关系。结果表明：脉冲电化学加工表面具有较小的摩擦系数和很好的抗磨损性能。     

电化学机械光整加工表面形貌研究

提出了用于圆柱表面精密光整的夹心式电化学机械加工装置核心部件设计方案,探讨了主要工艺参数对表面质量影响规律。对采用这种新型加工方法所产生表面的轮廓高度特性、间距特性、形状特性、轮廓峰分布及表面波纹度进行了试验研究,结果表明电化学机械光整表面轮廓以高频小振幅波度为主要成分。     

电化学光整加工对表面微观几何形貌的影响

通过对电化学光整加工过程中所得到的工件阳极表面微观几何形貌变化的分析，指出电化学光整加工过程是表面微观几何形貌的“圆角化”过程；结合表面微观几何形貌电化学溶解过程所建立的数学模型，提出“尖峰”形表面微观几何形貌的存在有利于改善电化学光整加工质量的观点，并在此基础上借助强化机械作用的手段，实现了大型反应釜内表面的光整加工处理，其表面粗糙度R“值可在短时间内降至0．04μm以下。     

采用电化学方法翻新锉刀

锉刀是工业生产中用量很大的工具,锉刀用钝后,切削性能下降,如继续使用会影响生产效率和加工质量,弃置不用又会造成浪费。本文介绍一种采用电化学加工翻新锉刀的方法。１．加工过程采用电化学方法翻新锉刀可分为预处理、化学及电化学浸蚀和后处理三个阶段。在预处理阶段,先用铜丝刷清除锉刀沟槽中的铁屑和油污,再将需要翻新的锉刀放入含２．５％氢氧化钠、８％磷酸钠的水溶液中进行除油处理,溶液温度控制在８０～９０°Ｃ,时间约３０～４０分钟,然后分别用温水和流动的冷水冲洗,除掉锉刀表面的碱性物质。在化学及电化学浸蚀阶段,…     

表面形貌的Motif评定方法及其发展

Motif方法是一种新的表面形貌评定方法，通过设定不同的阈值，可以将波度和表面粗糙度分离开来，它强调大的轮廓峰和谷对功能的影响，在评定中选取了重要的轮廓特征，而忽略了不重要的特征，介绍了2维Motif的参数和合并条件，然后对3维Motif方法的定义，评定参数及算法等进行了综述，并提出了推广这一评定方法需要注意的问题。     

电化学修形对齿轮表面微观几何形貌的影响

对电化学修形前后齿面微观不平度高度特征参数和形状特征参数进行了测量和统计计算,研究了电化学加工表面平滑化对齿面摩擦、齿面闪温及润滑状态的影响。     

用于表面微观形貌测量的光学方法

介绍了在表面微观形貌测量中常用的光学测量方法,分析了它们各自的原理和优缺点,并对光学法表面微观形貌测量技术的发展作了简要评述。     

扫描电化学池显微镜阿基米德螺旋快速扫描方法的研究

针对现有扫描电化学池显微镜(scanning electrochemical cell microscopy, SECCM)的扫描方法在扫描成像快速性上的不足,提出一种基于阿基米德螺旋线的新型SECCM快速扫描方法。传统跳跃扫描模式的跳跃高度是在没有先验知识的情况下靠人工经验设定的,为了避免碰撞其取值往往偏大,因此设置的扫描行程越长,消耗时间越久,速度慢、效率低。利用螺旋线轨迹预扫描快速获得待测平面的最高点,进而有效地降低了传统跳跃模式的跳跃行程,大幅提高了SECCM的扫描成像速度。此外,以螺旋线轨迹高速运动来检测最高点时,轨迹具有无冲击、因此样本运动过程无偏移,该扫描方法具有成像稳定性高的优点。通过带状金属表面成像实验表明,相对于传统跳跃扫描模式,阿基米德螺旋扫描方法在保证成像质量的同时扫描速度提高了约110%。可见提出的方法对提升SECCM扫描速度和成像质量有着重要的意义。     

聚酰亚胺自支撑膜的制备及其表面形貌

采用物理气相沉积法,在加热或不加热的抛光玻璃基片上蒸镀N aC l脱膜剂,再混合蒸镀均苯四甲酸二酐(PMDA)和二氨基二苯醚(ODA)两种单体,然后在空气环境中对样品进行热亚胺化。在去离子水中脱膜后获得厚度为100nm的聚酰亚胺自支撑膜。采用傅里叶变换红外光谱仪(FT IR)对样品进行化学结构分析并且根据谱线计算了不同热处理下薄膜的亚胺化程度。采用原子力显微镜,对样品进行表面形貌分析,结果表明给基片加热能改善聚酰亚胺薄膜的表面形貌。     

Fabrication of WC micro-shaft by using electrochemical etching

Tungsten carbide (WC) micro-shaft can be used as various micro-tools for MEMS because of its high rigidity and toughness. In this study, we performed fabrication experiments of the WC micro-shaft using electrochemical etching. H₂SO₄ solution was used as the electrolyte because it can dissolve tungsten and cobalt simultaneously. Optimal electrolyte concentration and applied voltage resulting in uniform shape, good surface quality, and high material removal rate (MRR) of a workpiece were experimentally selected. A straight micro-shaft with 5 μm diameter and 3 mm length was obtained by controlling the various machining parameters. Using the fabricated micro-shafts as tools, we machined a high quality micro-hole with 8 μm diameter and a micro-groove with 9 μm width in stainless steel 304 (304 SS).     

异相电解/超声波方法制备超细金属粉末

研究一种异相电解/超声波制备超细金属粉末的新方法,并应用该方法对制备超细铁粉末进行研究,成功地制备出超细金属铁粉末。该方法主要用于相对氢而言的较活泼金属粉末的制备,也可以应用于相对氢而言的不活泼金属粉末的制备,适用范围广,电解效率高,成本低,具有工业化应用前景。     

低温碱热法制备尖晶石型LiMn2O4纳米棒

以硫酸锰和氢氧化锂为原料,采用碱热法在KOH-NaOH体系中成功地合成了尖晶石型LiMn2O4纳米棒。利用X射线衍射(XRD)和扫描电子显微镜(SEM)对样品的结构与形貌进行了表征,结果表明:反应温度、反应时间和氢氧化锂的用量对产物的结构和形貌有较大影响。     

Modelling and analysis of hybrid electrochemical turning-magnetic abrasive finishing of 6061 Al/Al2O3 composite

This paper integrates the electrochemical turning (ECT) process and magnetic abrasive finishing (MAF) to produce a combined process that improves the material removal rate (MRR) and reduces surface roughness (SR). The present study emphasizes the features of the development of comprehensive mathematical models based on response surface methodology (RSM) for correlating the interactive and higher-order influences of major machining parameters, i.e. magnetic flux density, applied voltage, tool feed rate and workpiece rotational speed on MRR and SR of 6061 Al/Al₂O₃ (10% wt) composite. The paper also highlights the various test results that also confirm the validity and correctness of the established mathematical models for in-depth analysis of the effects of hybrid ECT- MAF process parameters on metal removal rate and surface roughness. Further, optimal combination of these parameters has been evaluated and it can be used in order to maximize MRR and minimize SR. The results demonstrate that assisting ECT with MAF leads to an increase machining efficiency and resultant surface quality significantly, as compared to that achieved with the traditional ECT of some 147.6% and 33%, respectively.     

光度法快速测定钼铁中硅、磷、铜

本文采用分光光度法,建立钼铁中硅、磷、铜三种元素含量的测定方法,本方法简单、快速,精密度高,准确度较好。     

Determination of phenyl acetic acid by cyclic voltammetry with electrochemical detection

The phenyl acetic acid (PAA) has been determined by cyclic voltammetry with electrochemical detection using CuGeO₃ nanowires as the glassy carbon electrode (GCE) modified materials. The electrochemical behaviors of the PAA at the CuGeO₃ nanowire modified GCE in neutral solution show that two pairs of electrochemical CV peaks are observed. Two anodic CV peaks are located at 0.31 V and −0.02 V for cv peak 1 and cv peak 2, respectively. The intensities of two anodic peaks vary linearly with the increase of the PAA concentrations from 0.01 to 2 mM. The detection limit is 82.1 μM and 9.1 μM for cv peak 1 and cv peak 2, respectively. The CuGeO₃ nanowire modified GCE exhibits good reproducibility, stability and sensibility.     

Observation of the surface stress induced in microcantilevers by electrochemical redox processes

The potential-induced surface stress of a solid electrode was investigated in an electrochemical cell. Gold-coated atomic force microscopy microcantilevers were used as working electrodes to measure the current–potential response (by cyclic voltammetry) and simultaneous bending characteristics in solutions of NaNO₃ and K₃Fe(CN)₆/NaNO₃. The observed changes of differential surface stress at a microcantilever electrode were attributed to electrochemical-potential-induced changes in surface charge density, ion adsorption/desorption, and electron transfer across the electrode surface. The potential dependent change in stress shows promise for the study of microscopic properties at the solid–electrolyte interface.     

Modeling and fabrication of microhole by electrochemical micromachining using retracted tip tool

Accurate microhole is a key feature for many kinds of micro parts widely used in diverse industries. But machining of microhole using traditional processes faces great challenges due to the thermal-mechanical effects. Electrochemical micromachining (EMM) is a potential technique to meet the requirement of high-quality microhole fabrication. However, the currently-used microtools suffer from some drawbacks such as stray dissolution, bell-mouth entrance and excess radial overcut. To overcome these limitations, a novel microtool with retracted tip structure is proposed in this work. A mathematical model has been developed to investigate the effect of retracted tip depth on machining accuracy. And an empirical formula is obtained based on the model to predict the diameter of the generated microhole. Experimental verification is performed on a home-made EMM system and reveals good correlation with the theoretical predictions. Using this novel microtool with optimum retracted tip depth, high-quality microholes have been fabricated on aluminum and 304 stainless steel sheets.     

结合连续法与数值图谱法的四杆机构连杆轨迹的尺度综合

由连续法得到满足再现轨迹综合要求的平面四杆机构。利用该机构连杆轨迹的谐波特征参数,通过模糊识别的方法,从已建立的对应机构的“数值图谱库”中找到更多组符合设计要求的机构。最后给出算例进行了验证。     

Interpretation of electrochemical measurements made during micro-scale abrasion-corrosion

This paper brings together and analyzes recent work based on the interpretation of the electrochemical measurements made on a modified micro-abrasion-corrosion tester used in several research programmes. These programmes investigated the role of abradant size, test solution pH in abrasion-corrosion of biomaterials, the abrasion-corrosion performance of sintered and thermally sprayed tungsten carbide surfaces under downhole drilling environments and the abrasion-corrosion of UNS S32205 duplex stainless steel. Various abrasion tests were conducted under two-body grooving, three-body rolling and mixed grooving-rolling abrasion conditions, with and without abrasives, on cast F75 cobalt-chromium-molybdenum (CoCrMo) alloy in simulated body fluids, 2205 in chloride containing solutions as well as sprayed and sintered tungsten carbide surfaces in simulated downhole fluids. Pre- and post-test inspections based on optical and scanning electron microscopy analysis are used to help interpret the electrochemical response and current noise measurements made in situ during micro-abrasion-corrosion tests. The complex wear and corrosion mechanisms and their dependence on the microstructure and surface composition as a function of the pH, abrasive concentration, size and type are detailed and linked to the electrochemical signals. The electrochemical versus mechanical processes are plotted for different test parameters and this new approach is used to interpret tribo-corrosion test data to give greater insights into different tribo-corrosion systems. Thus new approaches to interpreting in-situ electrochemical responses to surfaces under different abrasive wear rates, different abrasives and liquid environments (pH and NaCl levels) are made. This representation is directly related to the mechano-electrochemical processes on the surface and avoids quantification of numerous synergistic, antagonistic and additive terms associated with repeat experiments.