化学镀钴工艺试验小结

化学镀钴是利用强还原剂——次亚磷酸钠在化学镀钴溶液中的还原作用,使钴离子还原成金属钴,沉积在待镀零件表面。由于还原剂中含磷,所以获得的是钴磷合金沉积层。化学镀钴能避免电镀时因镀件几何形状复杂而造成的电力线分布不均,均镀能力差的缺陷,改善了镀层抗蚀,耐磨等性能,得到孔隙率低,均匀致密的镀层。化学镀钴层系磁性镀层,可应用于记忆存储器件上,由于它的记录性能优于传统的氧化铁涂层,因此化学镀钴引起了人们深入的研究。     

化学镀Co-Ni-P合金薄膜化学成分的考察

考察了影响化学镀Ｃｏ－Ｎｉ－Ｐ合金薄膜化学成分的因素,镀液中ｃｃｏ＾２＋／（ｃｏ＾２＋ｃＮｉ＾２＋）的比值越高和总金属离子浓度越低,薄膜的钴含量越高,镍和磷的含量越低。较高的ｐＨ值和较厚的薄膜会提高薄膜的钴含量,降低镍含量,磷元素倾向于偏聚在晶界上。     

SiCw-Co复合材料的制备及吸波性能的研究

为了改善SiC晶须的磁损耗性能,提高吸波性能,扩大其在科技、军事等领域的应用范围。本实验采用化学镀钴的方式制备SiCw-Co复合材料,选定化学镀溶液中硫酸钴的质量、化学镀的时间、化学镀的温度三个因素,设计了一个“三因素三水平”的正交实验,运用极差分析法讨论硫酸钴的质量、化学镀的时间和温度对SiCw-Co复合材料吸波性能的影响,最终得到制备SiCw-Co复合材料的最佳工艺。结果表明:在SiC晶须表面镀钴的最佳条件:化学镀溶液中硫酸钴的质量为8.0 g,化学镀时间为5 min,化学镀的温度为80℃。此时SiCw-Co复合材料的吸波性能最好,反射损失率最小为-20.12 dB,低于-10 d B的波段宽度约为3 GHz,同时具有一定的介电损耗和磁损耗能力。     

化学镀钴液中钴（Ⅲ）的分光光度测定

研究了钴－１－（２－吡啶偶氮）－２－萘酚及溴化十六烷基三甲铵体系测定钴。钴与ＰＡＮ二元配合物摩尔吸光系数可达９．４－１０＾３ｌ．ｍｏｌ＾－１．ｃｍ＾－１加入表面活性剂后，钴与ＰＡＮ生成三元配合物，摩尔吸光系数数值提高到２．１２－１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，钴含量０－２５μｇ／５０ｍｌ范围内经耳定律，方法应用于测定化学镀钴液中钴的测定。     

陶瓷粉化学镀钴工艺研究

根据化学镀原理,以镀后粉末的相对增重质量为主要指标,利用正交实验研究了在陶瓷粉末上进行化学镀钴。分析了钴离子浓度、酒石酸钠浓度、稳定剂浓度、温度以及pH对沉积效率的影响。测试了化学镀钴前后的微观形貌SEI图及XRD图。实验结果表明,溶液中的硫酸钴浓度、络合剂浓度、温度以及pH的增大,都会加快沉积速度。经X衍射分析表明,钴的晶体结构为体心六方结构。     

化学镀钴液中钴(Ⅲ)的分光光度测定

研究了钴（Ⅲ）－１－（２－吡啶偶氮）－２－萘酚（ＰＡＮ）及溴化十六烷基三甲铵（ＣＴＭＡＢ）体系测定钴。钴与ＰＡＮ二元配合物摩尔吸光系数可达９４～１０３Ｌ·ｍｏｌ－１·ｃｍ－１，加入表面活性剂后，钴与ＰＡＮ生成三元配合物，摩尔吸光系数值提高到２１２～１０４Ｌ·ｍｏｌ－１·ｃｍ－１，钴含量在０～２５μｇ／５０ｍｌ范围内符合比耳定律，方法应用于测定化学镀钴液中钴的测定。     

热处理对化学镀钴磷薄膜组织结构和磁学性能的影响

化学镀钴磷薄膜具有优良的磁学性能。研究了不同的热处理条件下薄膜组织结构对磁学性能的影响。化学镀钴磷薄膜镀态下为单一的α－固溶体,矫产力和矩形比较高,具有磁各向异性。     

加热温度对化学镀Co—P合金晶体结构和硬度和影响

化学镀Ｃｏ－Ｐ合金层在镀态下为晶态，是磷在钴中的固溶体，晶粒较为细小。随加热温度升高，晶粒长大、应力松驰，析出了金属化合物Ｃｏ２Ｐ和ＣｏＰ２相，并发生了α－Ｃｏ向β－Ｃｏ的同素异构转变。化学镀Ｃｏ－Ｐ合金层镀态硬度为４８２．４ＨＶ，经４００℃×１ｈ处理后可达峰值８２０．９ＨＶ。     

中国专利信息

一种化学镀锡溶液；微电子装置中的钴化学镀；化学镀钯液；一种化学镀银铜粉及其化学镀液和化学镀的方法；铁基粉末冶金制品的化学镀镍方法。     

化学镀研究现状及发展趋势

化学镀作为一种优良的表面处理技术,能够施镀于导体和非导体材料,镀层均匀,操作简便,因此一直受到工业上和学术界的关注.综述了化学镀的研究现状和主要化学镀层的应用领域,包括化学镀镍、化学镀铜、化学镀钴、化学镀银、化学镀锡、化学镀金以及化学镀钯等技术,并提出了化学镀技术的发展趋势.     

铁、钴、镍、铜和锌催化剂催化氨硼烷水解产氢性能研究

采用浸渍-还原法制备了铁、钴、镍、铜和锌催化剂,考察了其催化氨硼烷水解产氢性能,并优化了钴催化剂的制备条件和反应条件。结果发现,铁催化剂中铁以Fe₂B合金相存在,钴催化剂中钴以金属钴存在,镍催化剂中镍以金属镍和Ni（OH）₂·2H₂O存在,铜催化剂中铜以金属铜和氧化亚铜存在,锌催化剂中锌以Zn₄SO₄（OH）₆·4H₂O存在。铁、钴、镍、铜和锌催化剂催化氨硼烷水解产氢活性由大到小顺序为钴催化剂、镍催化剂、铜催化剂、铁催化剂、锌催化剂。显然,具有金属钴相的钴催化剂、金属镍相的镍催化剂和金属铜相的铜催化剂催化氨硼烷产氢活性高于具有Fe₂B合金相的铁催化剂。锌催化剂在制备条件下不能被还原为金属相,它几乎没有催化氨硼烷产氢活性。氯化钴与还原剂硼氢化钠的物质的量比为1∶1.3、还原温度为303 K时制备的钴催化剂催化BH₃NH₃水解产氢性能最佳。反应动力学计算表明钴催化剂催化BH₃NH₃水解产氢反应对氨硼烷浓度的反应级数为零级,对钴催化剂浓度的反应级数为一级,活化能为58 kJ/mol。     

氢氧化镍电极的修饰及电化学性能的研究

镍系列二次电池的正极活性物质Ni（OH）2的晶型和镍电极的制备工艺对电池的性能具有较大的影响。文章以镍-氢电池作为对象,着重研究作为电池正极的氢氧化镍电极。通过不同的方法制备电极的活性物质Ni（OH）2,以Co、Zn和稀土作为掺杂剂对电极进行修饰,并对不同掺杂方式构成的电池进行了测试。用金相显微镜来观察Ni（OH）2的外观、颗粒大小;通过恒电流放电曲线比较各电极的放电性能,并通过XRD谱图了解样品的晶型结构。电池性能测试结果表明：采用配位沉淀法制备的Ni（OH）2晶体为最佳;在添加剂方面,Zn、Co、Sm均对镍电极的电化学性能影响较大。     

Reactivity and codeposition of Co3O4 powderswith nickel in a Watts bath

The effect of the physico-chemical characteristics of Co3O4 powders on their reactivity in solution and their incorporation in a nickel matrix has been investigated in a Watts nickel plating bath. The results showed that the surface area of the powder present in suspension not only catalyses the adsorption or desorption phenomena occurring at the particle/solution interface but also has a significant effect on the incorporation of the particles into the nickel matrix. It has been found that the use of Co3O4 with high specific surface area (40m2g–1) significantly limits the growth rate of the electrodeposited composite coatings. Furthermore, it has been shown that the codeposition of these more reactive particles leads to significant changes in the microstructure and texture of the nickel matrix. Finally, it has been found that, according to their specific surface areas, the amount of H+, Ni2+ and Ni[B(OH)4]+ ions adsorbed on the Co3O4 oxide surfaces and the quantities of particles codeposited can vary considerably.     

Effects of electroplating variables on the composition and morphology of nickel-cobalt deposits plated through means of cyclic voltammetry

The effects of temperature and pH of the plating baths as well as the potential range and cycle number of cyclic voltammetry on the composition and morphology of NiCo deposits were systematically investigated. A reaction scheme corresponding to the NiCo codeposition was proposed. Nickel-cobalt deposits with the composition approximately equal to their corresponding plating solutions (based on the metal content) were formed when pH of the plating bath was equal to 2.0 and the potential range of CV was between 0 and −1.2 V. This complete depression in the anomaly of NiCo codeposition was attributed to the anodic dissolution of the freshly deposited metal atoms resulting in the simultaneous dissolution of the adsorbed monohydroxide species occurring between −0.3 and 0 V. The effects of temperature and pH of the plating bath, the cycle number and potential range of CV on the morphology, loading, or crystalline structure of NiCo deposits were also compared.     

Effects of the coating characteristics of Y(OH)3 on the electrochemical performance of spherical Ni(OH)2 at elevated temperature

The effects of the coating characteristics of Y(OH)₃ on the high-temperature performance of spherical Ni(OH)₂ were studied. The coating was performed by chemical surface precipitation under different conditions, and the characterization of Y(OH)₃-coating layer was evaluated accordingly. The electrochemical properties of three as-prepared samples with different coating surface were characterized and compared at different temperature. The results reveal that the sample with dense and porous surface retains the excellent performance at elevated temperatures, and the necessary coating amount is only 0.55 at.%. The mechanism analysis suggests that the chemical nature and morphology of the coating layer plays an important role in oxygen evolution reaction (OER). The coating surface with dense and porous morphology, larger relative surface content and higher utilization ratio of yttrium is more effective on controlling OER and improving the high-temperature performance of Ni(OH)₂ electrode for nickel-metal hydride (Ni/MH) batteries.     

Comparative experimental study on reactive crystallization of Ni(OH)2 in an airlift-loop reactor and a stirred reactor

The objective of this work is to study the reactive crystallization in an airlift-loop reactor (ALR) using the precipitation of Ni(OH)2 as a model reaction.The growth of Ni(OH)2 particles in an ALR and a stirred tank was quantified by scanning electronic microscope (SEM),X-ray diffraction (XRD),laser particle analyzer,tap densitometer and optical microscope,and the growth process of Ni(OH)2 particles is analyzed.It is found that the Ni(OH)2 particles prepared in an ALR have a better sphericity than those in a stirred tank and the growth of Ni(OH)2 particle tap density mainly depends on the size of crystallites:the bigger the size of crystallites,the bigger the tap density is.Based on these,the growth process of Ni(OH)2 particles in ALR is elaborated.Crystallites precipitated from solution aggregate to form large particles with much void.These constituting crystallites continue to grow up,that takes up the void inside particles and makes the tap density increase.     

A Chemical Route to Large-Scale Preparation of Spherical and Monodisperse Ni Powders

A facile chemical route to prepare a well-defined Ni powder on a mass-production scale without external heating was suggested. A highly concentrated Ni complex was formed between NiCl₂ and N₂H₄ solution, and subsequent addition of NaOH solution triggered serial reactions from the Ni complex decomposition via Ni(OH)₂ formation to the reduction of a Ni(OH)₂ gel into well-defined Ni spheres. The high temperature necessary for the reaction was attained not by external heating but by exothermic reactions such as complex formation and reduction. The preparation of monodisperse and spherical Ni powder was attributed to uniform distribution of the reducing agent (N₂H₄) within the Ni(OH)₂ gel.     

Electrochemical Quartz Microbalance characterization of Ni(OH)2-based thin film electrodes

The use of the Electrochemical Quartz Crystal Microbalance (EQCM) to study the proton intercalation performance of thin film Ni(OH)₂ layers, nowadays widely used as cathode electrode material in rechargeable Ni(OH)₂-based battery systems such as NiMH and NiCd, is reviewed. In addition, the impact of incorporating foreign metals in these layers on the electrochemical performance will be highlighted.Using EQCM much information can be obtained, as both the electrochemical response and accompanying mass changes can be measured simultaneously. EQCM was extensively used to investigate the effect of the conditions on the formation of Ni(OH)₂ thin layers, the α-to-β modification changes and the details of the redox mechanism. The proposed redox mechanisms differ in whether H⁺ or OH⁻ is transferred, the reactants and/or products are hydrated and cations from the solution take part in the reaction.By incorporation of other metals in the structure, the characteristics of thin Ni(OH)₂ layers can be tuned. This affects the oxidation and reduction potential, the reversibility, the stability of the structure and the oxygen evolution side reaction. Co²⁺ and Fe²⁺ were shown to replace Ni-sites in the hydrous oxide lattice, thereby forming very dense structures with higher stability. However, structural changes still occur in most cases. Due to this inhomogeneity, the layers are usually a combination of different structures, depending on the distribution of the incorporated metal(s). Suppression of the oxygen evolution reaction is reported for Co, Pb, Pd, Zn and Mn. The effects of Co and Mn are shown to depend on the incorporated amount. Co shifts the standard redox potential for the oxygen evolution reaction towards more cathodic potentials and decreases the oxygen overpotential significantly. Light-weight rare-earth elements also catalyze the oxygen evolution reaction.     

(Zn-Co)-TiO2复合电镀的工艺研究

研究了微酸性氯化物体系中（Ｚｎ－Ｃｏ）－ＴｉＯ２复合电镀的工艺,探讨了镀液组成及工艺条件对复合镀层中Ｃｏ及ＴｉＯ２含量的影响,得到了（Ｚｎ－Ｃｏ）－ＴｉＯ２复合电镀的最佳工艺。并对（Ｚｎ－Ｃｏ）－ＴｉＯ２复合镀层的耐蚀性进行了考察,与Ｚｎ－Ｃｏ合金镀层和锌镀层的耐蚀性进行了对比。     

氢氧化镍粉末的化学镀Co-Zn合金表面改性研究

采用化学沉积技术对由水溶液络合沉淀法合成的氢氧化镍粉末进行了表面包覆Co—Zn改性处理,利用扫描电子显微镜分析、比表面积测量、X一射线光电子能谱及原子吸收光谱等对处理前后氢氧化镍粉末的表面形貌、微晶结构、比表面积、元素化学态及镀层组成等进行了表征和研究。结果表明,Co—Zn合金镀层可以均匀包覆在氢氧化镍颗粒表面,氢氧化镍经化学镀处理后其表面微观组织形貌发生了明显变化。化学镀表面改性使氢氧化镍粉末的比表面积有所降低,镀层中的Co、Zn元素均以氧化态形式存在。