用改型滚筒解决镀件变形的方法

一滚镀件变形原因的分析在滚镀加工过程中,经常会出现电镀件变形的现象,严重时会出现滚筒电缆线绞断的状况.电镀件变形造成报废,影响了企业的信誉. 滚镀加工过程中电镀件变形的原因主要产生于潜浸式滚筒的结构上. 1 当滚筒以10～15r/min速度在溶液中滚动时,由于阴极导电线端导电锤上下敲击的作用使电镀件变形.随着电镀时间延长,导电锤镀层增厚,重量加大.其敲击作用则更为明显. 2 阴极导线引入处(尼龙空芯轴头处)留有     

贴片式电阻器滚镀工艺影响因素分析及改进

贴片式电阻器尺寸小,在滚镀时往往存在镀层分布不均匀和电流效率低的问题。分析了影响贴片式电阻器滚镀的因素(包括滚筒阴极导电结构、陪镀物种类和比例),对各因素进行了优化,最终令镀层分布均匀性与电流效率都得以提高。     

镀锌滚筒中阴极方式的改进

浸入式水平旋转滚筒的阴极,其连接方式从技术要求上讲,应该使其结构中的导电部位,在滚简运转时能始终保持与工件接触,使电流畅通无阻,又不无功消耗。但是要做到这一点,事实上也并不是一件容易事。本文经过多次改进和试验,最后采用链环式阴极结构,经生产实践取得了良好的效果。阴极链环靠自身重量埋入零件堆中,导电接触面积大,与零件充分接触,导电平稳良好。链环之间能够活动自如,减少了零件滚动时发生卡死变形等问题。此外,这种阴极还有一优点是使用寿命长,不易损坏,对提高质量和产量,都有明显的效果。     

滚镀铬工艺及其装置

一、滚镀铬的特点由于镀铬的电流效率低(滚镀铬液也不过20％左右),所以滚镀铬比滚镀其他常用镀层都要困难,以致滚镀铬工艺和设备具有一些与一般镀层滚镀工艺和设备不同的特点。主要点有: 1.滚筒的几何形状不同; 滚筒锌、铜、镍、银的滚筒一般都是六角形的,而镀铬滚筒都是圆筒形。 2.滚筒的材料不同; 一般滚桶都是采用聚氯乙稀硬塑料板或有机玻璃加工,用一导电辫子作阴极,使其与工件接触时用以输送阴极电流。而镀铬滚筒则是用金属网作筒壁,靠金属网与小零件接触时输送阴极电流。因此,零件与阴极的接触面大,以弥补镀液电流效率低的缺陷。     

镀银后出光工艺的改进

电器元件,尺寸小、数量大,一般用滚镀方法进行镀银,镀后出光采用铬酸溶液出光,由于铬酸溶液对银镀层的溶解,要求镀层厚度要适当加厚才能保证质量;同时铬污水要有治理措施才能排放;操作要有排风才能进行。为此我厂针对镀银后的出光处理进行了改进。改进后的方法对银镀层无损耗;取消了铬酸溶液,无废液排放;操作不需排风,减少了处理工序。其方法是用滚光取代铬酸出光处理,滚光机可以自制,用一台0.8瓩的电机,带一个φ300×500的塑料六方滚筒。塑料板厚10～12mm,滚筒转数为40     

矿渣冷却滚筒输送机的设计与改进

该文阐述了硫酸生产中矿渣冷却滚简输送机所起的作用及其结构特点，给出了冷却滚筒输送机工艺尺寸及有关参数的设计计算公式，分析了设计安装过程中的注意事项，并介绍了在实际生产中对其结构和运行缺陷的改进方法。     

滚镀瓦特镍研究

提出滚镀瓦特镍的工艺配方和操作条件，讨论了阴极电流密度，滚筒转速，孔眼大小等对镍电沉积性能如镍沉积速度，阴极电流效率、镀液分散能力等的影响。     

新颖的合叶式开门滚筒

滚镀具有生产效率高,不需挂具,而广泛的被用于小另件的镀锌、镍、铜及合金等。最常用的卧式滚筒为硬聚氯乙烯塑料板焊成的六角形有门滚筒,滚筒门的结构形式通常为扦闩式门,其结构如图一。但由于这种滚筒周围是密封的,镀液只能靠滚筒壁上的小孔流动,镀液的循环量慢,加上滚镀时的电流较大电压高,造成镀液升温快;并存在开关滚筒门的繁琐操作,增加了装卸零件的操作时间和劳动强度,同时门的强度有     

钢铁件镀银工艺的改进

发电机导电螺栓机械加工后外表面需电镀银以增强导电能力。螺栓的材质一般是钢铁基体。常规钢铁件镀银工艺为除油～除锈一活化～预镀碱钢一镀银。生产中我们发现此工艺镀银后，零件表面易出现锈蚀现象。为此，通过实验研究，我们采用镀锌层作为过渡层，较好地解决了这一问题。1常规镀银工艺产生锈蚀现象的原因及解决的办法导电螺栓镀银因配合尺寸的要求，镀层一般较薄，在10－2（）m。常规的镀银工艺中，镀铜层和镀银层相对铁基体均为阴极性镀层，不能对铁基体起到电化学保护作用。阳极性镀锌层作为过渡层，在电化学保．护中，锌层起牺牲阳…     

滚镀装置的改进和建议

1前言随着经济高度增长，生产率的不断提高，大型连续滚镀设备得到了普及。从使用的滚锻设备来看，滚筒的结构未有多少改进，普遍还存在许多不足之处。目前，电镀行业中按滚镀方式可分为：卧式滚镇机、微型滚镇机、潜浸倾斜式滚镀机等方式。2现行滚筒存在的问题2．1网扎现行使用的滚筒上的网孔是在简体表面均匀开设的o2～o7mm孔，孔距为5～IOm。。由于，滚筒将镜液与镀件分隔成两部分．镀液须通过网扎进入街内再与镀件发生电化学反应。反应后，镀液能否及时流出简外；新的镀液能否快速补充到街内，往往受到网孔尺寸限制。但是，在尽可能增…     

阴极辊结构和导电分析

针对电解铜箔生产的主要设备部件——阴极辊的导电分析计算和导电结构设计问题,从理论上进行了探讨,提出了导电分析计算模型及计算的通用公式,推导出电解铜箔的工作原理;增大电流密度可以提高铜箔的生产率,保证稳定的电流密度,可以生产出一定厚度的铜箔,并给出了实用的设计准则。同时对应用情况进行了介绍。     

Effect of Porosity in Catalyst Layers on Direct Methanol Fuel Cell Performances

Effects of porosity of catalyst layers (CLs) on direct methanol fuel cell (DMFC) performances are investigated using silicon dioxide (SiO₂) particles as a pore former. The pore size and volume of CLs are controlled by changing the size and content of SiO₂. As the size of pore formed by removal of SiO₂ increases, DMFC performances are enhanced. The augmentation in performances can be explained by facilitation of fuel transport to catalyst particles, increase of utilization efficiency of catalysts, diminishment in methanol crossover, reduction in activation loss and facilitation of water discharging out of CLs of cathode due to the controlled porosity in CLs. The enhanced fuel transport, accessibility of fuels to Pt catalyst surface, is proved by the active areas of Pt catalyst. In addition to the active area of Pt catalyst, porous CLs exhibit a decline in methanol crossover, leading to increase of open circuit voltage (OCV). The porous CLs also show improvements in activation loss due to high porosity, causing enhancement in DMFC performances. In aspect of pore volume contribution to cathode performance, the SiO₂ content is optimized. Based on the DMFC performances, it can be suggested that the optimum conditions of SiO₂ are 500 nm in size and 20 wt.% in content. The porosity effect on both electrodes appears as follows: the pores in cathode are more effective on DMFC performances (55.5%) than those of anodes (44.5%) based on the maximum power of DMFC, indicating that the pores in CLs facilitate removal of water from electrodes.     

担载膜受限烧结孔结构模型的改进及验证

针对担载膜受限条件下,复杂的堆积方式及垂直膜面方向出现的加速收缩将影响孔径的问题,对前期建立的担载膜孔结构预测模型进行了改进,从两个方面对模型的关键参数进行定量修正。考虑制备过程中颗粒可能形成的软团聚体对初始堆积方式的影响,对模型重要参数——初始孔隙率进行调整;并结合受限烧结应力模型计算担载膜在垂直膜面方向上的收缩速率和收缩率,研究该方向加速收缩对孔径的影响。在此基础上,采用改进的模型对ZrO2担载膜在800～1200℃烧结后,孔径、孔隙率、膜厚等微结构进行了预测。结果表明:与原模型相比,改进模型具有更好的适应性以及更高的计算精度,能更准确地预测不同烧结温度制备的担载膜的孔径和膜厚,为陶瓷膜孔径的预测与定量控制提供了有效的工具。进一步将模型计算值代入Hagen-Poiseuille方程,可以预测膜的纯水渗透通量。     

纳米活性炭/锌锰复合电极材料的制备及性能

使用溶胶-凝胶法合成锌掺杂二氧化锰的纳米晶电极材料,将其与干式振动滚压法制备的纳米活性炭混合制成超级电容器所需的片状电极。纳米活性炭材料为类球状颗粒,粒径约为50 nm,且为微孔和中孔并存的狭缝结构;制备的锌掺杂二氧化锰纳米晶材料为中孔占优的孔隙结构,含有纳米锌和氧化锌的成分,经XRD测试和比表面分析,得到此纳米晶材料的平均粒径小于30 nm。分析显示,经滚压振动研磨改性的纳米活性炭与10%纳米晶锌锰材料混合的电极材料具有较好的电容性能,比电容达到299 F.g-1。     

电解铜箔生产用新型阴极辊在线抛磨装置的设计

介绍了一种基于花键副传动的铜箔沉积用阴极辊在线抛磨装置,解决了传统装置中抛磨轮摆动惯量大,振动难以控制的问题,实现了抛磨轮的精确控制,有效消除了离线研磨中产生的纵向浅沟状刮削痕,提高了阴极辊辊面光洁度和一致性,使得生产的铜箔具有良好的各向同性性能。     

Characterization of porous lanthanum strontium manganite (LSM) and development of yttria stabilized zirconia (YSZ) coating

Cylindrical shapes of lanthanum strontium manganite (LSM) with varying amounts of pore former have been fabricated by the extrusion technique. Density of the sintered samples was found to decrease with the addition of pore former. Pore size distribution in a sintered sample with 37% porosity was within the range of 2–20 μm. Electrical conductivity of LSM samples with 20% and 32–37% porosity was found to be ∼92 S/cm and ∼80 S/cm, respectively. The thermal expansion coefficient of the LSM samples was found to be independent of porosity in the 20–37% porosity range. Sintered LSM tube was coated with YSZ by dip coating. Cross-sectional view of the coated sample showed formation of a dense layer of YSZ on the porous cathode structure.     

三种类型辊压机辊套对比

辊压机辊套目前有锻造母材+硬面耐磨堆焊、双金属离心复合铸造及柱钉辊套三类,通过对三种辊套的制造及材质特点、工作过程中辊面的可修复性、可靠性等分析对比得出,硬面耐磨堆焊辊套和柱钉辊套均具有较高的装配可靠性、抗疲劳强度及使用寿命,在控制物料粒度及严格控制金属异物进入的前提下,柱钉辊套是首选。     

Performance enhancement of strontium-doped lanthanum manganite cathode by developing a highly porous microstructure

A simple and promising template method was applied for the development of a highly porous microstructure, referred to as a macroporous structure (having pore size >50 nm), for a solid oxide fuel cell strontium-doped lanthanum manganite (LSM) cathode. Using poly(methyl methacrylate) beads of 2.9 μm size as the pore-forming templates, a porosity value of ca. 63 % was achieved. The electrochemical performance of the developed macroporous cathode was evaluated by measuring electrochemical impedance spectra of the symmetrical cells as well as power density of the full cells. The results indicated that due to enhanced oxygen diffusion and reaction kinetics, the macroporous structure was effective in reducing the interfacial polarization resistance of the LSM cathode and hence attaining a higher cell performance.     

Cyclic cold isostatic pressing and improved particle packing of coarse grained oxide ceramics for refractory applications

This study investigated the cold isostatic pressing of coarse grained alumina refractories applying either a cyclic pressure increase or a cycling at maximum pressure. Additionally the effects of the maximum pressure and the particle size distribution on physical, mechanical and thermomechanical properties were analyzed. The cyclic pressure increase resulted in a slightly higher apparent density and lower apparent porosity. A cycling at maximum pressure decreased the median pore size to some extent. Remarkably, an optimized particle size distribution resulted in a lower apparent porosity, lower median pore size and in a higher Young's modulus before and after thermal shock together with a slightly lower relative decrease of the Young's modulus. A higher pressing pressure which decreased the apparent porosity did not affect the Young's modulus. Thus, apparently the optimized particle size distribution improved the particle packing which was associated with a smaller median pore size. This smaller pore size increased the number of pores relative to the total porosity, which then acted as points of crack initiation and crack deflection limiting the length of propagating cracks in case of thermal shock. Thus, tailoring the pore size distribution is a promising starting point to improve the thermomechanical properties of refractories.     

支撑体孔径大小对Al2O3微滤膜完整性的影响

无机微滤膜不仅具有优良的热稳定性、机械稳定性和结构稳定性,而且化学稳定性高,耐腐蚀,不会被微生物分解,使用寿命较长,易于清洗和再生,更重要是无机微滤膜无毒．因此,它在食品、生化制药、催化反应等领域中作为物料的预处理和催化载体有着广阔的应用前景．然而,无机微滤膜真正起作用的是一层薄膜,