钙添加剂对可充锌电极性能的影响

通过直接化学反应法,化学共沉淀法以及物理混合方法在可充锌电极活性物质一氧化锌中掺入钙添加剂,研究了锌电极的充放电特必,放电容量及循环寿命等电化学性能,SEM分析表明直接化学反应法制备的样品是基面为四角形的薄片,化学共沉积法制备的样品是基面为六角形的多面体。XRD分析表面两种化学反应方法制备的样品均为锌酸钙晶体,由于制备过程中晶体优先生长方向不同而具有不同的形状。电极充放电实验结果表明,掺钙锌电极的电化学性能明显优于无钙锌电极,化学掺钙对锌电极电化学性能的改善优于物理混合掺钙。X射线照片表明由锌酸钙组成锌电极的表面活性物质分布较均匀,不掺钙的锌电极经多次充放电循环后电极表面已基本上没有活性物质。     

添加剂对锌电极性能的影响(英文)

为了改善镍锌电池的性能,同时研究电极中添加剂对锌电极性能的影响,选用正交设计对影响锌电极的4个因素(乙炔黑、Bi2O3、PbO、包覆La(OH)3的Ca[Zn(OH)3]2·2H2O)选择3个水平进行测试。对没有任何添加剂的氧化锌在20%KOH电解液中进行充放电循环实验,研究添加剂的作用。为了更好地解释锌电极放电容量衰减的原因,对正交实验的最差样品和最优样品放电产物所含的Zn和Ca的比例进行分析。通过表征,得出了在该实验条件下的电极添加剂的最优配比方案为:在5g样品中,乙炔黑0.02g,Bi2O3 0.5g,PbO 0.3 g,包覆La(OH)3的Ca[Zn(OH)3]2·2H2O)0.2g。     

纳米铁酸锌/丙氨酸改性聚乳酸复合磁性微球的制备和表征(英文)

以改进液相化学法合成铁酸锌纳米磁流体来代替传统的铁氧化物磁粉,同时以D,L型丙交酯与丙氨酸为单体进行本体聚合,得到氨基酸改性聚乳酸,再以改性聚乳酸包封纳米磁流体构建磁性高分子微球。采用X射线衍射、傅立叶红外光谱仪、核磁共振仪、扫描电镜、透射电镜、振动样品磁强计、热重分析仪等对所合成的材料进行表征。结果表明:所制备的材料为尖晶石型的ZnFe2O4纳米晶,粒径为20～45nm,磁饱和强度为32×10-3A.m2;丙氨酸成功接枝到了聚乳酸链上;铁酸锌纳米磁流体/聚乳酸复合微球的分散性较好,粒径为80～300nm,聚乳酸的包覆率为45.5%,磁饱和强度为10.6×10-3A.m2,ZnFe2O4经改性聚乳酸封装后仍然保持较好的磁饱和强度。     

A356合金二次无氰浸锌层的微观组织研究

本文利用扫描电镜（SEM）和原子力显微镜（AFM）观察了一次浸锌和二次浸锌不同时间下浸锌层的微观形貌，建立了无氰多元浸锌全过程模型。结果表明铝及其合金的浸锌过程是锌晶粒在基体上不断形核和长大的过程。浸锌初期主要是晶核形成期，浸锌后期主要是晶粒生长期；金属离子放电的高活性中心在金属表面上的低能量点上，多元合金中的铁、镍和铜是锌晶粒生长的异质晶核；二次浸锌得到的锌晶粒比一次浸锌更细小、均匀和致密，对基体覆盖能力好。二次浸锌时间为20-30S时，浸锌层的微观形貌最好。     

排渣炉鼻子内锌液液位的稳定控制

炉鼻子内锌液液面波动是产生锌灰、锌渣缺陷的重要原因,严重影响高级别镀锌板的表面质量.通过对排渣炉鼻子结构及加锌控制系统的研究,分析了液位波动的原因及原有液位控制策略的不足,提出了一种保持锌锅液位稳定的控制方法.生产实践表明,该方法效果良好,锌液波动很小,产品质量得到明显提升.     

The effects of polyethylene glycol (PEG) as an electrolyte additive on the corrosion behavior and electrochemical performances of pure aluminum in an alkaline zincate solution

The effects of zinc oxide and/or polyethylene glycol (PEG) as electrolyte additives on the corrosion and electrochemical performances of pure aluminum in 4.0 M KOH solutions were investigated by means of hydrogen collection, polarization curve, galvanostatic discharge, scanning electron microscopy (SEM), and energy dispersive analysis of X‐ray (EDAX). The addition of ZnO markedly inhibited the corrosion of aluminum in 4.0 M KOH solutions, resulting from the deposition of zinc with high hydrogen evolution overpotential in aluminum surfaces. The introduction of PEG in the alkaline zincate solution obviously improved the deposition of zinc by increase in the overpotential of zinc deposition, thus the corrosion rate of aluminum in the alkaline zincate solutions with PEG was further decreased. The enhancement effect of PEG on the inhibition of zinc oxide first increased and then decreased with increasing the content of PEG in the electrolyte. The electrolyte system with 0.2 M ZnO and 2.0 mM PEG presented the highest inhibition efficiency (98.8%) for the corrosion of aluminum. The results of galvanostatic discharge indicated that the aluminum anode shows excellent discharge performances in the 4.0 M KOH solution with 0.2 M ZnO and 2.0 mM PEG.     

锌夹层对铝合金超声搅拌摩擦点焊Hook缺陷的影响

对于铝合金的搅拌摩擦点焊,Hook缺陷是制约接头焊接质量的原因之一. 文中提出一种添加锌夹层的超声搅拌摩擦点焊新工艺,在利用超声可提高材料流动性及促进元素扩散的同时,添加纯锌中间层,使界面形成低熔点共晶进一步促进Hook区材料的冶金结合,从而改善Hook形貌,提升接头焊接质量. 结果表明,添加锌夹层可明显改善接头Hook形貌,显著提高了Hook区有效连接面积. 在不同热输入条件下,添加锌夹层后超声搅拌摩擦点焊接头的拉剪强度均有所提高. 当转速为600和1 200 r/min时,添加锌夹层比常规超声搅拌摩擦点焊工艺得到的接头拉剪失效载荷分别提升了21.36%和12.79%.     

基于银氧化物电极的高比能电池研究进展

基于银氧化物电极(银电极)的高比能电池具有比能量大、输出功率高、放电平稳、安全可靠等优点;银电极作为此类电池的关键部件,决定着电池性能的优劣。简要介绍了银电极的工作原理和制备方法;详细分析了银电极中AgO分解、两坪阶电位、活性物质利用率和高倍率放电性能等研究现状;综述了锌银、铝银和锂银等几类基于银电极的高比能电池的原理与特点、发展与应用、性能与改进方法等;对基于银电极的高比能电池的发展方向进行展望。     

Investigation of the microstructure of an aqueously corroded zinc wire by data‐constrained modelling with multi‐energy X‐ray CT

The compositional microstructure of a zinc sample that has been subjected to aqueous oxidation has been investigated using a data‐constrained modelling (DCM) approach combined with multi‐energy X‐ray micro computed tomography (CT) data. High‐resolution X‐ray CT data sets were acquired at the Shanghai Synchrotron Radiation Facility (SSRF) at beam energies of 9 and 10.5 keV. CT images were used to reconstruct the three dimensional chemical compositional distribution via the DCM approach, with spatial resolution at the order of a micron. The results indicate that the interface between zinc and zinc oxide is characterized by a triple layer where the innermost layer consists of zinc and zinc oxide and the outer layers of zinc oxide with differing density.     

Effects of additives on zinc electrodeposition from alkaline zincate solution

The effects of additives on the surface and cross-sectional morphologies of zinc deposits on iron substrate from alkaline zincate solution were characterized by scanning electron microscope (SEM). The cathodic reaction mechanisms under various concentrations of additives were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. It is found that with increasing the additive A content in the bath solution, the nucleation overpotential (NOP) value is obviously increased and the inhibition effect is strengthened. This may be mainly due to the adsorption of additive A on the cathodic electrode surface, which can cover the active sites and block the discharge reduction. The results of EIS analysis indicate that the rate-determining step of zinc electrodeposition process is changed from mixed control step into electrochemical reduction step in the presence of additive A. However, any quantity of additive B has little effect on the NOP value and the inhibition effect is not obvious. Furthermore, addition of additive A and additive B at the same time displays the strongest inhibition effect and shows a strong synergism because of their co-adsorption on the cathodic electrode surface.     

锌粉颗粒形状对机械沉积无结晶镀层结构的影响

以球状锌粉和片状锌粉为原始锌粉借助于机械镀工艺制备了无结晶锌防护层，运用光学显微镜（OM）、扫描电子显微镜（SEM）观察了镀层的结构形貌；采用XRD技术分析了镀层的物相组成；采用贴滤纸法进行了镀层的孔隙率测试。研究结果表明，片状锌粉制备的镀层比球状锌粉制备的镀层表面要平滑、光亮。球状锌粉制备的镀层中锌粉颗粒呈紧密堆积，部分锌粉颗粒发生塑性变形；片状锌粉制备的镀层中的锌粉颗粒呈层片状叠加，镀层中锌粉颗粒没有发生明显塑性变形。两种形状锌粉制备的镀层均为锌基多相混合体系，镀层中没有固溶体、化合物等合金相产生，属于锌基复合镀层。锌粉颗粒形状对镀层中颗粒之间的结合机理没有显著影响，两种镀层中锌粉颗粒间均以机械咬合为主。     

烟化炉产氧化锌烟尘的介电特性及温升特性

为了研究微波焙烧脱除氧化锌烟尘中氟氯的可行性以及氧化锌烟尘的吸波特性,采用谐振腔微扰法对不同物料密度氧化锌烟尘的介电特性（ε′,ε″和tanδ）进行测定。氧化锌烟尘的介电常数、介电损耗和损耗角正切值与氧化锌烟尘的表观密度成正比。在微波场下研究物料质量和微波功率对氧化锌烟尘升温特性的影响。结果表明,氧化锌烟尘对微波具有较强的吸波能力,其表观升温速率与微波焙烧功率成正比,与质量成反比,在8 min内温度可到达800℃。     

Development of peeling tool for micro-EDM

We propose a simple and fast fabricating method of tool electrode for micro-EDM. A ‘peeling tool’, a wire coated with a different material, has been developed as an interim product for a microelectrode. A zinc layer was coated by electroplating on a tungsten electrode of 100 μm diameter. The zinc layer makes both handling and chucking of the electrode easy. Part of the zinc layer is instantly ‘peeled’ by a single discharge, exposing tungsten electrode under the zinc layer undamaged and the exposed electrode can be used in microhole drilling by EDM. Time-resolved imaging revealed the peeling process dynamically.     

Hydrothermal synthesis of Zn4SO4(OH)6·5H2O and its application as anode material for nickel/zinc batteries

The anode material Zn4SO4 (OH)6 · 5H2O for nickle/zinc batteries was synthesized by hydrothermal method and was identified by XRD techniques. TG/DAT measurements reveal that the products lose lattice water at 145 ℃ and decompose to 3ZnO · ZnSO4 at 274 ℃. Cyclic voltammetry and recharging/discharging results show thatCV curves have good symmetry, the ratio of oxidation area to reduction area for each curve is about 1, and the peak potential EPa and EPc have little change with the scanning rate. At 50th circle, more than 65 % of theoretical capacity is obtained while at the same condition, zinc oxide electrode only remains 35% of theoretical capacity.     

Effect of zinc powder content on tribological behaviors of brake friction materials

Brake friction materials with different zinc powder contents (0, 2, 4, 6, 8 wt.%) were fabricated via powder metallurgy method. The results indicate that with the increasing zinc powder content, the density and thermal conductivity of the materials gradually increase, while the hardness decreases monotonously. With increasing zinc powder content, the curve of the nominal friction coefficient shows fluctuating trend but the lowest friction coefficient also shows an increase. However, the wear rate and braking noise of the friction material monotonously decrease with increasing zinc content. This effect may be attributed to the transformation of the tribological mechanism from adhesive wear and abrasive wear to adhesive wear. The brake friction material with 4 wt.% zinc powder exhibits both the best tribological and noise performance.     

不同导电剂对锌镍电池中锌电极性能影响的研究

本文采用常规电化学测试,研究了添加铜、镍和石墨对锌电极电化学性能的影响.电化学测试结果表明,添加铜的锌电极具有较高的放电容量,较好的循环稳定性以及较稳定的中值电压.通过比较不同铜添加量对锌电极性能的影响,确定了铜的最适宜添加量为5%(质量).恒电位极化测试证明,添加铜的锌电极不仅腐蚀电位提高,而且腐蚀电流明显降低,说明...     

Probability of precision micro-machining of insulating Si3N4 ceramics by EDM

Electrical discharge machining (EDM) is used as a precision machining method for the electrically conductive hard materials with a soft electrode material. But recently we succeeded to machine on insulating material by EDM. The technology is named as an assisting electrode method. The EDMed surface is covered with the electrical conductive layer during discharge. The layer holds the electrical conductivity during discharge. For micro-EDM, the wear of tool electrode becomes lager ratio than the normal machining. So the micro-machining is extremely difficult to get the precision sample.

In this paper to obtain a fine and precise ceramics sample, some trials were carried out considering the EDM conditions, tool electrodes material and assisting electrode materials. Insulating Si₃N₄ ceramics were used for workpiece. The machining properties were estimated by the removal rate and tool wear ratio. To confirm the change of micro-machining process, the discharge waveforms were observed. The micro-machining of the Ø0.05 mm hole could be machined with the commercial sinking electrical discharge machine.     

Pressure leaching of zinc silicate ore in sulfuric acid medium

Zinc silicate ore was characterized mineralogically and the results showed that zinc exists mainly as hemimorphite and smithsonite in the sample. Sulfuric acid pressure leaching of zinc silicate ore was carried out to assess the effect of particle size, sulfuric acid concentration, pressure, reaction time and temperature on the extraction of zinc and the dissolution of silica. Under the optimum conditions employed, up to 99.25% of zinc extraction and 0.20% silica dissolution are obtained. The main minerals in leaching residue are quartz and small amounts of undissolved oxide minerals of iron, lead and aluminum are associated with quartz.     

铝锌合金在3%NaCl溶液中的电化学行为

通过测定铝锌合金试样在3%NaCl溶液中不同极化电位下的EIS,分析铝锌合金的溶解行为。完善了传统的溶解－沉积—再溶解机理,研究锌活化铝的作用。结果表明,富锌相的存在使得合金溶解加速,溶解较为均匀。     

表面封闭法对铝阴极耐腐蚀性的影响

目的提高锌电积中铝阴极表面耐腐蚀性能,从而延长其使用寿命,降低生产成本。方法对铝阴极采用不同的表面处理工艺,对耐腐蚀处理后的铝阴极进行了铜加速乙酸盐雾试验、电液腐蚀失重试验和工业扩大化试验研究,考察其耐腐蚀性能。结果在经历120 h盐雾腐蚀后,溶胶-硬脂酸封闭试样仅9.5%的表面被腐蚀,沸水封闭、铈盐封闭试样表面分别有50%与27%左右的面积遭到腐蚀破坏,出现腐蚀孔与腐蚀裂纹,而未经处理的普通铝板表面则已完全被腐蚀破坏。在电解液腐蚀失重试验中腐蚀32 min后,溶胶-硬脂酸封闭试样的单位面积失重达到0.4 mg/cm~2,沸水封闭、铈盐封闭试样的单位面积失重较为相近,均在0.9 mg/cm~2左右,普通铝板的单位面积失重高达1.3 mg/cm~2。工业扩大化试验中,溶胶-硬脂酸封闭后的铝阴极在锌电积生产40 d期间失重约为1.8%且其电流效率保持在91%左右,而普通铝阴极失重则达7.7%。使用90 d后,溶胶-硬脂酸封闭的铝阴极板还能正常使用,而普通铝阴极由于腐蚀破坏需要更换。结论采用沸水封闭、铈盐封闭和溶胶-硬脂酸封闭处理后的铝阴极板耐腐蚀性能均有相应提高,其中以溶胶-硬脂酸封闭工艺最佳。可见表面封闭法对于提高铝阴极耐蚀性延长使用寿命起到了较好作用,同时也保持了较高的电流效率。