泡沫镍制备中脉冲电沉积镍研究

研究了泡沫镍制备过程中脉冲电沉积镍工艺参数(电流密度、脉冲频率、占空比)对沉积速率、镍沉积层的晶体结构和微观形貌的影响.最佳脉冲电沉积工艺参数为:电流密度2.0 A/dm2,脉冲频率1000 Hz,占空比1∶5.此时获得的镍沉积层结构平整,粒度分布均匀,晶体结构完整.     

电沉积工艺参数对泡沫镍成形速度的影响

介绍了电解液喷射沉积制备泡沫镍的原理,讨论了相关电沉积参数对电沉积速度的影响,并且对影响因素进行了基础研究.结果表明,电流密度及电解液喷射速度与沉积速度呈线性关系,电流密度越大,成形速度越快;喷射速度越高,成形速度也越快;喷嘴口径大时,相应增大了电铸面积,提高了电铸的速度;电铸速度随喷嘴扫描速度的提高,略有下降.     

电沉积泡沫镍的DTR控制研究

研究电解液的组成和电沉积过程对电流密度的影响,指出决定厚尺度泡沫镍沉积厚度比(DTR)的决定因素是电流密度的控制,而电解液的电导率及主盐浓度也有重要影响.     

喷射电沉积镍阴极极化行为研究

通过阴极极化曲线的测定研究了硫酸盐电解液喷射速度u(流速)对电流密度jc和阴极过电位ηc的影响．结果表明。电流密度为140A／dm^2时，喷射速度由0．83m／s增大到5．00m／s，阴极过电位从1．48V增至8．52V．与槽镀搅拌作用相比，电解液流速增大。有利于氢还原析出，导致过电位显著增大．随电流密度增大，阴极上析氢步骤逐渐取代水合镍离子电化学还原步骤成为整个过程的控制步骤，过电位可达12．03V。     

氮气雾化喷射沉积变形镍基高温合金

利用氮气雾化喷射沉积技术成功地获得了宇筋骨和变形镍基高温全金柱形坯。沉积坯整体致密、含气量低、成分均匀、组织细化。研究了和应变速率对沉积材料的高温变形抗力、工艺塑性的影响以及热加工和经５种没热处理后材料的显微组织特征。材料的最终力学性能达到或超过同成分的铸锻的标准要求。     

镍的摩擦辅助喷射电沉积过程及沉积效率

分别使用传统喷射电沉积和摩擦辅助喷射电沉积技术制备一组不同沉积时间的镍沉积层,并采用非接触式表面三维形貌仪对其表面形貌进行观察,采用XRD分析沉积层的晶粒大小和织构随沉积时间的变化,用TEM观察沉积层组织机构的不同,通过沉积层的厚度分析对两种方法的沉积效率和稳定性进行比较。结果表明:传统喷射电沉积镍层随着沉积时间的增加表面逐渐变得粗糙,沉积时间由20 min增加至120 min时,粗糙度Ra值由212 nm增加至282 nm,而摩擦辅助喷射电沉积镍层可以始终保持光亮平整,Ra值由最初的228 nm逐渐减小,并最终稳定在171 nm左右;摩擦辅助装置的加入对喷射电沉积效率影响很小,但使沉积的均匀性和稳定性得以提高;同时,该装置细化晶粒,使平均晶粒大小由15.6 nm减少至10.9 nm。     

电沉积法制备泡沫Ni的组织结构

观察了电沉积法制备泡沫Ｔｉ过程中各阶段的Ｎｉ层组织形变化,结果表明：电镀后和６００℃空气处理４ｍｉｎ后的Ｎｉ层均为细晶组织,但经８５０℃和９８０℃的氨分解气氛处理４０ｍｉｎ后,均达到充分烧结,泡沫Ｎｉ表面平整致密,由大晶粒多晶Ｎｉ组成。     

喷射电沉积制备泡沫金属喷嘴型腔流场分析及实验研究

利用有限元分析软件ANSYS,分析了喷射电沉积工艺中不同喷嘴型腔里的流场变化趋势,研究了电镀液在型腔内的压力和速度分布规律.结果表明:无论采用圆形还是扁平形喷嘴在型腔径向截面上压力分布较均匀,速度呈类抛物线形分布;流体的压力梯度和速度梯度随与入口端距离的增大而增加.通过泡沫金属喷射电沉积成形实验验证,显示理论分析与实验结果吻合.     

连续泡沫镍制造技术

连续泡沫镍由于具有三维网状结构、孔隙率高、比表面积大、质量均匀，因此成为MH／Ni及Cd／Ni电池理想的电极基板材料，并在许多领域得到广泛应用。作者综述了连续泡沫镍的制造技术，介绍了导电化、电沉积镍、热解还原等步骤的具体工艺；对比了化学镀镍、浸涂导电胶、真空气相沉积等不同导电化方法的优缺点；着重介绍了连续泡沫镍主要生产厂家的制造方法和装置；以及适用于MH／Ni及Cd／Ni电池生产连续泡沫镍的性能指标及其评价方法；并展望了连续泡沫镍广阔的市场前景和发展方向。     

喷射电沉积镍磷合金沉积速度试验研究

为了在亚磷酸盐体系中得到工艺稳定、光亮且沉积速度快的镍磷合金镀层,采用自行研制的喷射电沉积装置在45钢基体上进行了四因素五水平正交试验,优选出沉积速度最佳的工艺条件:电流密度300 A/dm2,镀液温度60℃,初始间隙1 mm,相对运动速度375mm/min.     

激光重熔喷射电沉积纳米晶镍涂层微观结构

采用喷射电沉积法在45钢基体表面制备了纳米晶镍涂层,研究了激光重熔工艺对组织的影响.用扫描电镜、X射线衍射仪和显微硬度计分析了涂层表面形貌、微观结构和显微硬度.结果表明,在优化的工艺参数下,喷射电沉积制备的镍涂层表面较平整、结合较致密,由平均尺寸为13.7 nm的纳米晶颗粒组成,但晶粒间仍有一定的间隙;经激光重熔后,熔融区内的晶粒尺寸明显减小,使涂层致密化程度得以提高并使涂层与基体由机械结合变为冶金结合,因此激光重熔处理后涂层的显微硬度明显提高.     

The Structure of Electrodeposited Nickel

Here are presented the results of laboratory studies on various types of acid rhodium plating electrolyte, with particular reference to sulphate and phosphate-sulphate solutions, but including exploratory trials on phosphate, fluoborate and sulphamate electrolytes. The sulphate electrolyte is preferred for general purposes.

For the first two electrolytes, examination is made of the effects of variations in preparative procedure on the characteristics of electrolytes of the same nominal composition, and the influence of composition and deposition factors on the internal stress of deposits.

Factors affecting the incidence of cracking of thick rhodium deposits are discussed, and on the basis of laboratory and field experience, practical recommendations are made concerning the formulation of sulphate electrolytes and the optimum operating conditions for the production of rhodium deposits in the thickness range 0·002-0·002” from this type of solution. Procedures are detailed for either the rhodium or silver/rhodium plating of the basis metals most commonly involved in industrial applications.     

Synthesis and Characterization of Electrodeposited Nanocrystalline Nickel

NANOCRYSTALLINE materials exhibit ultra-highstrength,superior wear resistance and enhancedsuperplastic formability compared with theirconventional coarse-grained counterparts ll~31.As aresult,there has been a great emphasis on studyingthese materials.And the synthesis of nanocrystallinemetals and alloys is a particularly important topic.Many synthesis techniques for production ofnanocrystalline materials have been developed,such asinert gas condensation,ball milling,sol-gel technique,spu…     

Mechanical Properties of Electrodeposited Nanocrystalline Nickel

In this paper, dense bulk nanocrystalline (nc) nickel electrodeposits with various grain sizes were produced by using high frequency pulse current and strong electrolyte flushing. The effects of the grain sizes on the mechanical properties were discussed for room and a medium temperature. It was found that the properties of the deposited nickel such as microhardness, corrosion resistance and yield stress (at room temperature and 473 K) were improved substantially with the decrease in the grain size. A deviation of yield stress from the Hall-Petch relationship for nc nickel was observed when the grain sizes were decreased to less than 70 nm at room temperature. A low yield stress value of nc nickel was obtained at a temperature of 673 K as a result of its thermodynamic instability.     

Surface Preparation and Porosity in Electrodeposited Nickel

The porosity of electrodeposited nickel has been measured by an autoradiographic technique after the surface of the copper basis had been prepared by a number of different methods. Statistical analysis of the results shows that porosity is independent of the method of preparation.     

脉冲电沉积纳米晶体镍镀层热稳定性的研究

采用脉冲电沉积法制备了纳米晶体镍镀层，平均晶粒尺寸约为20nm。采用热分析法、透射电子显微镜(17EM)和X射线衍射方法(XRD)研究了纳米镍镀层的热稳定性。结果表明，纳米晶体镍镀层晶粒开始明显长大温度约为255℃，晶粒长大过程分为两个阶段：低温晶粒异常长大阶段(200～300％)和晶粒正常长大阶段(300～500％)。原始镍镀层的(111)和(200)面双织构在低温晶粒异常长大阶段仍存在，但在正常长大阶段逐渐消失。100％加热后镍镀层显微硬度略有增高，随后随着加热温度的升高不断降低。     

The Adhesion of Electrodeposited Nickel To Brass

Although tin-zinc alloy plating has been practised commercially in England for several years, American knowledge of and interest in the process developed by the Tin Research Institute did not become appreciable until 1950; this delay was attributable partly to the continuing restrictions on tin use in America, and partly to normal reluctance on the part of industry to adopt a new process without extensive and time-consuming tests. The acute shortage of cadmium which developed late in 1950 provided the necessary stimulus, and the concurrent development of an all-potassium bath, which made the process directly competitive with cadmium-plating in speed of deposition, greatly aided in convincing the American electroplating industry that the tin-zinc process represented a worth-while innovation. Re-imposition of tin controls has somewhat clouded the issue but there is little doubt that the tin-zinc alloy deposit will find a place in industry. This paper presents operating data for the all-potassium bath and explains a discrepancy between English and American results using the sodium bath.     

电沉积镀镍层的无铬钝化工艺

采用正交试验法筛选了一种以植酸、钼酸钠和缓蚀添加剂为基本组成的无铬钝化液。通过电化学阻抗谱测试,确定了最佳成膜时间;通过5%CuSO4点滴试验、10%NaCl浸泡试验和极化曲线测试,对电沉积镀镍层无铬钝化后的耐蚀性能进行了研究。结果表明,采用本无铬钝化工艺后,镀镍层耐蚀性能良好。     

The Causes and Prevention of Pitting in Electrodeposited Nickel

The determination of the activation overpotential/current density relationship (η_A—i) during the electrodeposition of metals is subject to errors owing to the changing surface topography of the substrate. Under these circumstances, the true current density varies continuously as electrodeposition proceeds. To overcome this difficulty, a technique has been developed which involves the use of a platinum cathode which is coated with a very thin deposit of copper prior to each determination of η_A at constant i. Removal of the deposit is effected anodically and automatically terminated before oxygen gas can be evolved. This avoids the possibility of gas bubbles adhering to the platinum and causing errors in the subsequent plating stage. Although the studies have been confined to copper, it is considered that the method is of general application. The preparation of copper sulphate electrolytes has been investigated and, using highly purified electrolytes in conjunction with the techniques described, it has been found possible to obtain linear Tafel lines during the electrocrystallisation of copper.