直线刃阴极数控电解加工工艺试验研究

采用直线刃阴极进行电解加工平面的工艺试验,对试验结果进行分析,得到电解液压力、阴极进给速度、电源电压、极间初始间隙与表面粗糙度、切削深度的关系曲线.在此基础上,选取优化的参数组合,实现了直纹曲面的加工.     

槽起始段有不同斜率产品的电解加工

通过对槽起始段具有不同斜率产品的电解加工特点进行分析,设计了一种不同加工间隙的新式阴极头,并制定了相关的加工工艺.应用该阴极头和加工工艺对产品进行了电解加工,达到了预期效果.加工出的槽起始段可有不同的斜率.     

钛合金喷注器微小孔电解加工应用

设计了一种航天用喷注器微小孔电解加工工艺方案,通过对微小孔结构阴极的设计、阴极绝缘处理方法的研究,对电解加工参数进行了分析和优化,实现了钛合金材料微小孔的稳定加工.基于上述研究成果,设计了电解分度工装,成功实现了某型号钛合金喷注器微小孔电解加工.     

基于流体动压效应的扫描阴极掩膜电解加工试验

针对目前掩膜电解加工深度溶解能力受限问题，以微凹坑阵列为研究对象，提出了基于流体动压效应的扫描阴极掩膜电解加工新方法。利用高流速电解液冲刷微凹坑表面堆积的电解产物，提高深度溶解能力，并且借助扫描阴极射流产生的流体动压效应使掩膜与工件表面动态贴合，从而简化工艺装置设计。基于加工试验，探讨了不同平底阴极结构和加工参数耦合作用对微凹坑尺寸变化的影响，最终实现直径259.8μm、深度44.1μm和直径418.1μm、深度102.7μm微凹坑阵列的加工，论证了扫描阴极掩膜电解加工方法具有提高深度溶解的能力。     

活动阴极模板电解加工微小群孔的研究

研究了活动阴极模板电解加工微小群孔加工工艺,建立了加工过程的数学模型,利用有限元方法对加工表面电流密度分布进行了数值求解.试验研究了活动阴极模板绝缘层厚度、阴极厚度及孔的分布对群孔成形精度的影响.结果表明,绝缘层厚度越大,加工孔的成形精度越好,而阴极厚度和孔分布对群孔成形精度没有明显影响.进行优化参数加工,所加工的4种不同孔径群孔均匀性较好,成形精度较高.     

TC4复合材料电解钻孔加工技术研究

基于TC4复合材料研究了大余量去除和大直径孔的电解钻孔加工技术.首先,设计了工具阴极结构,在工具阴极侧面绝缘基础上采用电场仿真研究了工作圈高度对加工效果的影响,再针对不同钻孔深度进行流场仿真分析,揭示电解钻孔加工流场分布规律并探究了工具阴极端面出液孔数量对加工稳定性的影响;其次,对陶瓷绝缘和电泳绝缘两种不同绝缘方式下的...     

叠加磁场方孔电解加工试验研究

为了提高型孔电解加工精度和表面质量,分别采用在方孔阴极体的四壁和芯部镶贴永磁体两种方案进行电解加工工艺试验.结果表明,与不叠加磁场相比,在相同工艺参数下,四壁镶贴永磁体有利于改善表面粗糙度,芯部镶嵌永磁体有利于减小杂散腐蚀.     

基于CFD软件球形阴极流场仿真试验研究

应用CFD软件对数控电解加工的球形阴极电解加工流场进行了仿真.根据计算机仿真结果,结合工艺试验,指导阴极内部流场的优化设计,初步实现了工具阴极的计算机辅助设计与分析.     

阴极周期跳跃式微细电解加工的正交试验研究

阴极周期跳跃式微细电解加工是为解决加工中电解液更新困难、电解产物很难排除的难题而提出的一种加工方法.基于自行研制的加工装置,设计了以加工间隙为优化目标的正交试验方案,通过对0.5 mm厚不锈钢板正交试验数据的方差分析,找出了影响加工精度的主要因素,得到了实现加工间隙更小化的工艺参数优化组合.     

复合进给对锥形孔电解加工过程的影响

为提高锥形孔加工精度,采用圆锥阴极复合进给的电解加工工艺方案,首先分析了阴极复合进给对加工间隙流场的影响,从促进加工间隙电解产物的排出及优化间隙流场的角度证明了复合进给能有效提高电解加工精度。基于自主研制的复合进给电解加工装置系统进行了工艺试验,研究了复合进给参数对锥形孔孔径及锥度的影响。最后,采用优选的工艺参数加工出的锥形孔能满足现有喷油嘴锥形孔的加工要求,且加工过程稳定。     

单颗粒金刚石平面划擦大理石的实验研究

本文采用单颗粒金刚石沿不同的切削路径（不同间距切痕或重叠切痕）与不同切削深度的组合形式进行了平面划擦广西白大理石的试验。分析了两种切削路径下各加工参数对切削力FZ的影响,结果表明：当切削深度小于10μm时,两种切削路径对各道切痕的切削力FZ无明显影响;当切削深度大于30μm时,切削路径对切削力FZ影响增大,且在相等切削深度的条件下,切痕重叠时的加工性能比不同切痕间距时的加工性能差;在不同间距切痕条件下,小间距大切削深度（L〈200μm,ap〉70μm）或大间距小切削深度（L〉600μm,ap〈10μm）的组合形式的加工性能较好。     

A new candidate as the cathode material for intermediate and low temperature SOFCs

In order to develop the new cathode materials suitable for intermediate and low temperature solid oxide fuel cells (IT/LTSOFCs), LaNi1-xFexO3(x=0.4-0.8) (LNF) materials were synthesized using coprecipitation method. Their structures and morphologies were investigated by XRD and SEM, and their electronic conductivities at different temperatures were measured by dc four terminal method. Fuel cells were fabricated to evaluate the electrochemical properties of the LNF materials as cathodes at different temperatures. The performance of 450-497 mW·cm-2 was obtained in the temperature region of 580-650 ℃ for the LaNi0.2Fe0.8O3 cathode, and of 209-227 mW·cm-2 at 400-500 ℃ for the LaNi0.4Fe0.6O3. The excellent fuel cell performances indicate that the LNF materials are good cathodes for IT/LTSOFCs.     

Research on the Penetration Depth in Aluminum Reduction Cell with New Type of Anode and Cathode Structures

In this article, a cold water model experiment based on the principle of similitude was conducted to study penetration depth and to investigate the rules of penetration depth (the thickness of bubble sheet) in new anode structure electrolytic cell. New structure anodes and new structure cathodes were designed to examine penetration depth induced by anodic gas in the electrolytic cell. A high-speed camera was used to take photographs of the water model experiment. After that, photographs were analyzed by Image-Pro Plus software. The results revealed the effect of different parameters such as slit width, anode–cathode distance, electrolyte level, and gas rate on the penetration depth. The results provide several meaningful suggestions in selecting electrolysis apparatus. Finally, through dimensional analyzing, the penetration depth criterion equation of the 1/2 anode structure electrolytic cell was obtained. In sum, water model experimental results provide theoretical and experimental basis for the new anode structure and new cathode structure electrolysis cell’s design and practice.     

Simulations of the dielectric constant of bonding materials and field emission properties of CNT cathodes

The effect of the dielectric constant (k) of bonding materials in a screen-printed carbon nanotube (CNT) cathode on the field enhancement factor was investigated for high-efficiency CNT cathodes using the ANSYS software. The values obtained by a simulation study were compared to the experimental results obtained for screen-printed CNT cathodes. The field enhancement factor increased as the dielectric constant decreased, reaching a maximum value at a dielectric constant of 1, the value for a vacuum. The findings indicate that the larger sheet resistance of the bonding materials, after the firing process, can be attributed to the larger emission current of the CNT cathode. From these results, it was concluded that the best bonding materials for screen-printed CNT cathodes should have a low dielectric constant and a high sheet resistance. This finding can be used as criteria for selecting bonding materials for use in CNT pastes for highly efficient CNT cathodes.     

Electrochemical Wear of Carbon Cathodes in Electrowinning of Aluminum

Cathode wear is the main factor limiting the lifetime of high-amperage aluminum electrolysis cells with graphitized cathodes. The current article deals with an investigation of cathode wear in a laboratory cell, where the cathode is directly exposed to the electrolyte during electrolysis. The wear was shown to be electrochemical in nature and dependent on the current density, the rotation speed, and the depth of prefabricated slots in the cylindrical cathodes. The wear mechanism is discussed with respect to kinetics influencing the electrochemistry as well as the solubility of aluminum carbide in the electrolyte.     

小孔径内壁螺旋形结构电解加工试验研究

以小孔内壁为加工对象,设计螺旋型刃阴极,研究电解加工小孔径内壁螺旋形结构成形规律。分析了小孔径内壁螺旋槽电解加工成形基本理论,设计并制作了螺旋形阴极;基于ANSYS软件进行电场仿真,分析不同加工间隙和电压时的电场分布情况;利用FLUENT软件分析不同初始加工间隙时的流场分布情况,通过流场分析优化了阴极结构,解决了由于存在涡流现象导致加工质量差的问题;通过正交试验分析各参数对加工结果的影响规律。采用优化参数加工所得螺旋槽最大深度为0.672 mm,误差为0.017 mm,表明数控电解加工小孔径内壁螺旋形结构切实可行。     

THERMIONIC EMISSION OF CARBONIZED La-Mo CATHODE

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纳米阴极材料电弧分散特性的理论分析

采用扫描电子显微镜观察了纳晶结构和粗晶结构的W-20%Cu和Cu的首击穿烧蚀形貌,指出纳晶电弧烧蚀痕迹分散,烧蚀比较轻微;常规材料烧蚀比较集中,且烧蚀比较严重。通过分析阴极材料的微观结构,建立了多晶材料电子所处势场结构模型,通过数值计算得出：晶粒越小,对应价电子子能带间能隙越大。分析认为,纳米晶结构的阴极材料电弧分散是由于较大的能隙阻碍了大量电子同时参与导电并迫使阴极斑点快速运动,从而避免大电流产生的焦耳热所导致的严重烧蚀。     

Electrochemical performance of La1-xSrxCuO3-δ-Sm0.15Ce0.85O1.925 composite cathodes in IT-SOFCs

The cathode material La1-xSrxCuO3-δ( x =0.15, 0.2, 0.3, 0.4) was synthesized by a sol-gel method. X-ray diffraction reveals that a single phase of perovskite is formed. The investigation of the electrical properties suggests that La0.7Sr0.3CuO3-δ has the highest electrical conductivity. La0.7Sr0.3CuO3-δ powder was mixed with different amount SDC (Sm0.15Ce 0.85O1.925) powder (5wt.%-30wt.%) as composite cathodes. Electrochemical properties of the composite cathodes were researched further. Investigation suggests that the addition of appropriate amount SDC to La0.7Sr0.3CuO3-δ can improve the electrochemical properties and obtain better cathodic performance. Using La0.7Sr0.3CuO3-δ-SDC composite materials as a cathode based on SDC electrolyte, higher current density and power density at intermediate temperatures can be obtained.