温度与pH值对Ni-Fe合金异常共沉积的影响

对从硫酸盐/氯化物槽液中沉积的Ni-Fe合金镀层进行详细研究的结果表明,Ni-Fe合金的异常共沉积确实存在。文中详细说明了沉积层成份、沉积效率、镀层应力、延展性能与pH、温度和电流密度之间的关系。并根据X射线衍射图提供了镀层结构与含铁量关系的数据。     

离心高速电镀铬工艺研究

为提高圆筒状工件内壁电镀铬的沉积速度,采用自行研制的离心高速电镀铬装置。研究了电流密度与沉积速度、晶粒尺寸及镀层硬度的关系。结果表明,离心高速电镀铬的极限电流密度及沉积速度、镀层硬度均增大,镀层晶粒更细致。     

镍钨合金电沉积的电流效率和镀层显微硬度

通过调节镀液中不同的Ｎｉ／Ｗ比例、温度和沉积电流密度,研究在焦磷酸盐体系中镍钨合金电沉积的电流效率、沉积层和组成和显微硬度。实验结果表明：合金共沉积的电流效率不高。为了尽量提高合金的沉积电流效率,主要途径宜增大镀液中硫酸镍和钨酸钠的浓度;提高合金沉积电流密度,降低镀液中［Ｎｉ］／［Ｗ］比例,则镀层中的钨含量增大;合金沉积层的显微硬度随镀层中的Ｗ含量提高而增大。     

离心高速电镀镍工艺研究

为提高电镀镍的沉积速率以提高劳动生产率 ,采用自行研制的离心高速电镀镍装置。研究了电流密度与沉积速率、晶粒尺寸及镀层硬度的关系 ,结果表明 :采用此装置 ,镀液在阴极表面切向流速、极限电流密度及沉积速率均增大 ,使得镀层晶粒更细致 ,硬度更高。     

脉冲铜沉积层织构及形貌的研究

采用脉冲电沉积工艺制备了铜沉积层,研究了电流密度、脉冲频率和占空比对铜镀层织构的影响。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)分析了铜镀层的织构和形貌。实验结果表明,低电流密度下为(200)晶面择优取向,高电流密度下为(111)晶面择优取向,频率越高则择优取向越强。低频脉冲下制备的沉积层平整致密。     

峰值电流密度对脉冲电沉积Ni-Co-CNTs复合镀层机械性能的影响

研究了峰值电流密度对脉冲电沉积Ni-Co-CNTs复合镀层机械性能的影响。结果表明:当峰值电流密度升高时,镀层表面变得粗糙;随着峰值电流密度的增加,镀层中碳的质量分数先增加后下降,当峰值电流密度为80 A/dm~2时,镀层中碳的质量分数达到最大值;镀层的显微硬度和抗拉强度均在峰值电流密度为100 A/dm~2附近时达到其最大值,且高于直流电沉积时所得镀层的显微硬度值和抗拉强度值。说明采用脉冲电沉积工艺可以提高镀层的机械性能。     

基于电沉积法回收废水中铝离子的最佳工艺参数分析

基于电沉积法,针对某铝箔生产企业所产生的高含铝离子废水,通过不同峰值电流密度下形成的电沉积试样的相关电化学曲线测试结果和镀层中的Al质量分数分析,确定所采用电沉积法的最佳峰值电流密度为9 A·dm-2,此时沉积层中铝质量分数为33.21％,原子数量占比为24.69％.     

信息

半光亮镍镀液及其使用方法一种能在基体表面电沉积半光亮镍镀层的镀液包含:(1)硫酸镍;(2)可溶性氯乙酸盐、醋酸盐、乙二醇或丙酸;(3)丁炔二醇。该半光亮镍镀液可以在一个很宽的电流密度范围内获得无硫半光亮镍沉积层。该工艺不含香豆素,不需添加醛类物质,但所得镀层厚度均匀,电压稳     

脉冲电沉积制备Ni70Cu30合金镀层的工艺研究

采用赫尔槽试验法在柠檬酸盐体系镀液中以脉冲电沉积制备Ni-Cu合金镀层。分别采用X射线衍射仪、扫描电子显微镜及能谱仪分析了不同工艺条件下所得镀层的结构、形貌及组成,探讨了镀液中铜含量(WL)和电流密度(jk)对Ni-Cu合金镀层的铜含量(WC)及性能的影响,最终获得了WC与WL、jk之间关系的经验公式。结果表明,镀层中铜含量与镀液中铜含量呈一次线性相关,与电流密度呈幂指数关系。以经验公式为指导,综合考虑镀层外观和镀液稳定性,最终得到电沉积制备Ni70Cu30合金镀层的优化工艺参数为:WL=12%,jk=0.8A/dm2。     

复合搅拌电沉积Ni-Al2O3的研究

施加空气-磁力复合搅拌电沉积制备Ni-Al2O3复合镀层,并研究了电流密度对共沉积速率、电流效率及所得复合镀层形貌的影响。结果表明:复合搅拌状态下,共沉积速率随电流密度的增加而加快,而电流效率随电流密度的增加先升后降;采用适宜的电流密度,可制得形貌状况良好的Ni-Al2O3复合镀层。     

硫酸盐电铸镍内应力的影响因素

研究了NiSO4·6H2O质量浓度、NiCl2·6H2O质量浓度、温度和阴极电流密度等工艺参数对硫酸盐电铸镍层内应力的影响。通过铜箔阴极弯曲法半定量地测定了镍铸层的内应力,采用扫描电镜和X射线衍射表征了镀层在不同应力状态下的表面形貌和微观结构。结果表明,当NiSO4·6H2O质量浓度为100～150g/L时,其变化对内应力影响较大;镀液中氯离子浓度的增加会增大镀层内应力;低温和大电流密度条件下获得的镀层具有大的拉应力,高温小电流则有利于降低镀层的拉应力。     

脉冲电镀中脉冲参数对镍镀层显微硬度的影响

采用传统的瓦特镀液通过脉冲电镀制得纯镍镀层。研究了脉冲参数对镀层微观形貌与显微硬度的影 响。结果表明:镀层表面形貌为胞状结构;随着脉冲峰值电流密度的增加,胞状结构的尺寸逐渐变小,镀层显微硬度先增 加后减小;随着占空比的减小,最大显微硬度值对应的峰值电流密度增大,占空比减小到一定值后,峰值电流密度的改变 对显微硬度影响不再明显。     

脉冲喷射电沉积镍工艺的研究

由于直流电沉积镍使用极限电流密度下,沉积速度低。本文介绍脉冲喷射电沉积的方法制备镍镀层。研究了脉冲频率、占空比、电流密度及糖精对镀层晶粒尺寸的影响。结果表明：镀层晶粒尺寸随脉冲频率、平均电流密度的增大而减小;随空比的增大而增大。少量糖精的加入能有效降低镀层晶粒尺寸。     

连续电镀锌镍合金的研究

提出了一种高氯化铵弱酸型镀液体系连续电镀锌镍合金工艺，研究了m(Ni^2 )/[m(Ni^2 ) m(Zn^2 )]、氯化铵浓度，电流密度、温度、PH值对镀层镍含量的影响，推导出连续镀的镀速计算公式，采用此工艺可获得外观良好、镍含量在13％－15％的锌镍合金镀层。     

Influence of cathodic overpotential on grain size in nanocrystalline nickel deposition on rotating cylinder electrodes

Nanocrystalline (nc) nickel was electrodeposited using rotating cylindrical electrodes (RCD) from a Watt’s bath containing saccharin. The effects of cathode rotation speed and saccharin concentration on the cathodic overpotential and grain size were studied. The grain sizes are presented as a function of the cathodic overpotential. All reported cathodic overpotentials were corrected for ohmic overpotentials. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to determine the deposit grain size. In addition, the influences of cathode rotation speed and current density on the morphology of nanocrystalline nickel were observed by scanning electron microscopy (SEM).     

The effect of current density on properties of electrodeposited nanocrystalline nickel

Nanocrystalline nickel electrodeposits were fabricated at 18, 25 and 50 mA cm^–2 using a sulfamate-based electrolyte. The crystallite size of the deposits was evaluated by XRD technique and their mechanical properties were characterized by tensile testing. The results of this study confirmed that increasing the current density results in an increase in the grain size of nickel deposits. The strength of the deposits decreased consistently with increasing the crystallite size. However, the deposit fabricated at 50 mA cm^–2, in comparison to nickel with conventional grain size (>1 m), showed a relatively low strength and a surprisingly low tensile elongation. It is suggested that the enhanced evolution of hydrogen at high current densities is responsible for the formation of larger crystals and the unusual low tensile elongation.     

防止锡回流变色的连接器电镀工艺

分析了连接器锡镀层发生回流变色的原因。开发了一种能有效地控制连接器表面锡的回流变色和锡须形成的新工艺。该工艺能形成较大的结晶粒度,并能控制结晶取向从而获得光亮的外表。采用在镍层表面再电镀一层镍磷合金形成N i/N i-P双层镀层的方法,改善了镍层表面纯锡的回流变色问题。最后采用与常规碱式后处理有很大差别的酸式后处理方法对锡层表面进行处理。新工艺有效地解决了连接器表面纯锡的回流变色问题,实现了工业化生产。     

The preparation and structure of electrodeposited sponge cadmium electrodes

A method is described for preparing coherent sponge cadmium electrodes on cadmium-plated substrates by electrodeposition from cadmium chloride solutions in the absence and presence of potassium chloride. The deposit morphology was shown to be a function of current density, pH, plating bath composition and temperature. Of the five main deposit types observed, only one, a sponge with very small crystallites, displayed high electrochemical activity when cycled in KOH solution and had sufficient coherence and adherence to its substrate to be considered suitable as a battery electrode. This material had a useful capacity approximately twice that of conventional electrodes, implying a net increase in battery capacity of at least 30% if conventional sintered plate positives were used. In addition, the elimination of the sintered nickel substrate and the possibility of continuous production methods promised a lower cost. In a separate series of experiments, ultramicrotome sections of the sponge deposits were examined by transmission electron microscopy. For specimens having a high electrochemical activity (more than 70% of the deposit being capable of reversible cycling in KOH solution) crystallite dimensions up to several microns in length and 0.5 to 1 micron in diameter appeared to predominate. This was consistent with measurements of the depth of oxidation observed on block cadmium electrodes and with the structure inferred from powder X-ray diffraction examination.     

脉冲电镀镍及其性能的研究

采用瓦特镀镍液,研究了脉冲占空比、平均电流密度、温度对电沉积速率,镀层光亮度和镀层在w=3.5%的NaCl溶液中耐蚀性的影响.用扫描电镜研究了直流和脉冲镍镀层的表面形貌.结果表明:电沉积速率随脉冲占空比、平均电流密度及温度的增大而加快;镀层耐蚀性,光亮度随脉冲占空比增大而变差,随温度、平均电流密度的增大先变好后变差.较佳脉冲电镀条件为:平均电流密度0.75 A/dm~2,脉冲占空比5%,温度45～50 ℃,pH 2.5～3.0.X射线衍射分析结果表明,与直流镀镍相比,脉冲镍镀层在(111)晶面存在择优取向,镀层更致密,性能更好.