IrO2基体上阳极电沉积MnO2的电化学行为

采用极化曲线和循环伏安等电化学方法, 对不同温度下IrO₂电极在MnSO₄镀液与硫酸溶液中的电化学行为进行对比研究, 并以镀液中极化曲线上不同电流密度值进行阳极电沉积, 测量镀速大小. 研究结果表明:IrO₂电极在镀液中同时发生阳极电沉积反应和析氧副反应, 阳极电沉积反应对析氧反应具有明显的抑制作用; MnO₂的阳极电沉积过程较复杂, 存在Mn³⁺中间产物, 既有Mn³⁺→Mn⁴⁺的电沉积过程, 也有Mn³⁺的水解及水解产物的脱附的过程, 水解反应的存在严重降低了MnO₂的阳极电沉积的电流效率; MnO₂的阳极电沉积存在一定的电位区间, 在此区间, 镀速存在最大值.     

化学沉积镍-铁-磷合金和它的伏安行为(英文)

在以次亚磷酸钠为还原剂 ,硼酸为缓冲剂和柠檬酸钠为络合剂的碱性介质中 ,研究了镍_铁_磷合金化学沉积条件 (pH值 ,温度及 [Fe2 + ]/([Ni2 + ]+[Fe2 + ])物质的量比 )对沉积速率和镀层组成的影响 ;并由此建立镀液稳定的最佳沉积工艺 .实验表明 ,镀液中硫酸亚铁对沉积镍_铁_磷合金有阻碍作用 (降低了化学沉积速率 ) ,造成镀层中铁含量不高 (小于 2 0 % ) ,使用循环伏安技术研究了镍_铁_磷合金的电沉积机理 .结果发现铁对次亚磷酸钠的氧化不起催化作用 ,提高镀液温度和pH值有增加沉积速率之效     

离子液体电沉积CuInxGa1-xSe2薄膜

采用循环伏安法(CV)对离子液体Reline中三元CuCl₂+InCl₃+SeCl₄体系和四元CuCl₂+InCl₃+GaCl₃+SeCl₄体系的电化学行为进行了研究。研究表明,In³⁺并入三元CIS(Cu-In-Se)薄膜体系和Ga³⁺并入四元CIGS(Cu-In-Ga-Se)薄膜体系均有两种途径：一是发生共沉积,二是直接还原。利用电感耦合等离子体发射光谱(ICP)和扫描电镜(SEM)对沉积电势、镀液温度和主盐浓度对CIGS薄膜组成、镀层表面形貌的影响进行了测试,结果表明通过工艺参数的选择可以控制Ga/(Ga+In)和CIGS薄膜组成并得到化学计量比为Cu_1.00In_0.78Ga_0.27Se_2.13的薄膜。     

Cu含量对Ni-Cu-P化学镀层组织结构和性能影响

利用化学镀法制备出Ni-Cu-P合金镀层,研究了镀液中CuSO4·5H2O含量对合金镀层沉积速率和成分的影响. 通过XRD和SEM表征了不同CuSO4·5H2O质量浓度下Ni-Cu-P合金镀层的组织结构和表面形貌,运用极化曲线评价了合金镀层在质量分数为3.5%NaCl溶液中的耐蚀性能. 结果表明,随着镀液中CuSO4·5H2O质量浓度的增加,镀层沉积速率和P含量不断下降,Ni-P镀层中P的质量分数为14.98%. 当镀液中CuSO4·5H2O质量浓度为1.0 g/L时,P的质量分数为4.21%;镀层中Cu的含量随着镀液中CuSO4·5H2O含量的增加而增加. 当添加量为1.0 g/L时,镀层中Cu的质量分数达19.04%;镀层的结晶度随着Cu含量的上升不断增大,Cu的加入使镀层的表面形貌更加光滑;镀层的耐蚀性能随着镀液中CuSO4·5H2O含量的增加先上升后下降,当镀液中CuSO4·5H2O质量浓度为0.4 g/L时,Ni-Cu-P镀层表现出最优的耐蚀性能.     

Fe-Ni-S软磁薄膜的电沉积

酸性镀液中以硼酸为缓冲剂、柠檬酸三钠为配合剂,在紫铜箔上电沉积得到非晶Fe-Ni-S合金薄膜。 采用扫描电子显微镜和能谱分析技术(EDS)研究了镀液组成和沉积条件对镀层表面形貌和组成的影响。 结果表明,在镀液中加入2 g/L C7H5O3NS（糖精）和0.4 g/L 1,4-丁炔二醇可获得表面平整无裂缝和较小内应力的合金镀层;电流密度和镀液pH值对镀层组成影响较小,但施镀温度对镀层组成影响较大。 获得了理想的镀液组成和沉积条件,所得Fe73Ni9.5S17.5薄膜的X射线衍射表明其为非晶结构,在室温下具有较高的饱和磁化强度(Ms约为876.25 kA/m)和较低的矫顽力(Hc约为4.96 kA/m),具有良好的软磁性能。 循环伏安曲线和阴极极化曲线均表明,镀液中CS(NH2)2会促进Fe-Ni-S共沉积。     

表面活性剂对陶瓷基底化学镀镍的作用机理及镀层性能的影响

采用酸性化学镀技术在Al₂O₃陶瓷片表面沉积Ni-P镀层,通过电感耦合等离子体发射光谱,X射线衍射光谱和扫描电子显微镜等分析测试,对镀层的成分、物相和形貌进行了表征,考察了表面活性剂种类、掺量等因素对镀层表面性貌和性能的影响。结果表明,当添加5 mg·L^-1 SDS时,镀速从14 μm·h^-1增加到17 μm·h^-1,随表面活性剂添加量继续增加,镀速呈减少趋势。添加表面活性剂能够不同程度的消除化学镀Ni-P镀层固有的胞状组织,提高表面致密性和平整性;镀层自腐蚀电流密度从43 μA·cm^-2减小至3.5 μA·cm^-2,镀层的耐腐蚀性能显著提高。根据电化学理论和实验规律,探讨了表面活性剂在化学镀镍磷合金反应过程的影响机理。     

在离子液体[BMIm][BF4]中电沉积光亮金镀层

在离子液体1-丁基-3-甲基咪唑四氟硼酸盐（[BMIm][BF₄]）中以HAuCl₄·3H₂O为主盐、通过添加5,5-二甲基乙内酰脲（DMH）和胞嘧啶可得到色泽光亮、厚度达1.5 μm的金镀层,沉积过程中阴极电流效率可达到100%。SEM和XRD测试结果表明,DMH和胞嘧啶具有细化晶粒、平整镀层的作用。电化学测试结果表明,DMH可分别与Au³⁺、Au⁺形成配合物Au（DMH）₄^-、Au（DMH）₂^-,抑制了还原过程的表面转化步骤,从而增加了阴极极化,起到光亮镀层、细化晶粒的作用;胞嘧啶可在金核表面吸附,从而可以进一步光亮镀层、细化晶粒,与DMH有协同作用。循环伏安测试研究了镀液的电化学行为,研究表明在此体系中Au³⁺的还原为两步还原过程,分别为Au³⁺→ Au⁺和Au⁺→ Au。此外DMH和胞嘧啶的添加不会带来副反应。     

电沉积条件对钴-锰合金结构和磁性能的影响

以柠檬酸为络合剂和硼酸为缓冲剂的酸性硫酸盐镀液中电沉积Co-Mn合金,循环伏安实验显示Co-Mn的起始共沉积电位约-1.282 V(vs.Hg-Hg2SO4 , sat.K2SO4)。借助扫描电镜(SEM)、能谱分析(EDS) 、X射线衍射(XRD)和振动样品磁强计(VSM) 研究了沉积条件对镀层结构和磁性能的影响。结果表明,Co-Mn镀层的组成受沉积条件影响较大;在镀液pH 4.0时,随着阴极电流密度从10 mA•cm-2增加到40 mA•cm-2,镀层中锰含量从0.3 at%增大到6.6 at%;镀层结构由hcp的固溶体转为fcc的固溶体;随着镀层中锰含量增加,膜的饱和磁化强度开始增大,然后降低,最大饱和磁化强度为1926.0 kA•m-1,膜的矫顽力在31.6 ~ 33.9 kA•m-1范围。     

Ti基化学镀Ni-P和Ni-P-Cg镀层晶化动力学

利用化学镀技术在Ti基体材料表面制备了Ni-P合金镀层和Ni-P-Cg复合镀层。利用SEM、XRD和EDS等分析了镀层的晶化过程,用差热分析仪研究了Ni-P合金镀层和复合镀层的晶化动力学,运用Ozawa、Freeman-Carroll、Achar和Coats-Redfern方法对非等温动力学数据进行了分析和比较。结果发现,复合镀层的特征温度T_m和晶化激活能E均高于Ni-P合金镀层,而热焓值｜ΔH｜却低于Ni-P镀层;计算出Ni-P合金镀层和Ni-P-Cg复合镀层晶化激活能分别为308.9 kJ·mol^-1和412.99 kJ·mol^-1、指前因子A分别为58.03 s^-1和77.84 s^-1,确定了Ni-P合金镀层和复合镀层晶化动力学方程。     

KCl-LiCl-MgCl2熔盐体系中共电沉积制备Mg-Li合金及理论分析

在670 ℃的KCl-LiCl-MgCl₂熔盐体系中通过共电沉积方法制备了Mg-Li合金,并进行了理论分析。循环伏安表明：670 ℃时,锂在镁上(镁预先沉积到钼丝上)的欠电位沉积形成了液态的Mg-Li合金;当MgCl₂质量分数为10%时,出现了Mg-Li合金成核。极化曲线表明：在含有5% MgCl₂的熔盐中,MgCl₂的极限电流密度为0.35 A·cm^-2,超过此值时,Mg和Li就能产生共电沉积。对沉积物进行X射线衍射和电感耦合等离子体发射光谱(ICP)分析表明：通过恒电流电解得到了3种不同相的Mg-Li合金。在电流密度为6.21 A·cm^-2电解2 h条件下,只有当MgCl₂质量分数小于10%时,才能得到Mg-Li合金。并通过Nernst和浓差极化方程讨论了MgCl₂浓度对于Mg-Li合金形成的影响。Mg-Li合金中锂的含量能够通过熔盐中的MgCl₂浓度配比和电解参数来控制。实验证明这种直接从原料入手,通过共电沉积制备Mg-Li合金的新方法是可行的。     

Factors affecting the quality of plutonium deposits by electrodeposition

Ultra-high resolution alpha spectrometry by microcalorimetry has demonstrated a dramatic improvement in alpha energy resolution over silicon based detectors. To characterize the optimal resolution obtained by the microcalorimeter alpha spectrometers, high quality deposits that are virtually massless are required; electrodeposition is the preferred method for the preparation of high quality deposits. In order to better understand the factors that contribute to lower alpha energy resolution and deposit yield, we have conducted a study to determine the effect of some of the parameters that are used for preparing electrodeposits. We have compared four different electrodeposition methods and four different substrate materials to determine the effect on the deposit yield and alpha energy resolution of plutonium as measured by full width at half maximum using silicon based detectors. Furthermore, we wanted to understand the effect of contaminants from environmental samples on electrodeposits. Therefore, the effect on deposit yield and alpha energy resolution with several common soil constituents (Al³⁺, Eu³⁺, Fe³⁺, K⁺, Lu³⁺, Mg²⁺, Na⁺, Zn²⁺) have been studied.     

Electrodeposition of zinc + cobalt alloys.: Relation between the electrochemical response and the composition and morphology of the deposits

The electrodeposition of cobalt and zinc + cobalt alloy in aqueous chloride solution has been studied on vitreous carbon electrodes under different concentration conditions (total concentration of metallic ion 0.1 mol dm ⁻³, chloride ion 1 mol dm ⁻³, pH = 3), particularly during the initial stages of the deposition process. For the alloy a relation has been found between the shape of the current-time transients, the morphology of the deposits, the stripping analysis and the results of X-ray microanalysis. The different alloy phases present in the deposits were identified using X-ray microanalysis data, stripping voltammetry results and literature data.The results indicate that the electrocrystallization of cobalt is inhibited even at very low concentrations of zinc in solution: voltammetric and galvanostatic results indicate that the deposition potentials always correspond to more negative values than those for cobalt deposition. This inhibition depends strongly on both the metallic ion ratio in solution and the applied overpotential (or current density). For Zn(II)/Co(II) ratios greater than 1/9, low overpotentials (or low current densities) favoured homogeneous and compact deposits that were rich in zinc and were mainly composed of γ-phases of zinc + cobalt alloy. However, when high overpotentials or current densities were used and/or when the Zn(II)/Co(II) ratio was very low (< 1/9), dendritic and non-homogeneous cobalt-rich deposits were obtained.     

Zinc-cobalt alloy: electrodeposition and characterization

Zinc-cobalt alloy electrodeposits offer enhanced corrosion protection to steel, compared to zinc deposits. A near neutral zinc-cobalt alloy sulfate bath was developed. In the absence of β-naphthol and sodium lauryl sulfate (SLS), only a light grey and non-uniform deposit was obtained. Addition of boric acid yielded a grey and uniform deposit. To obtain the grey uniform alloy deposit, the optimum bath composition was: 0.5 M ZnSO₄, 0.5 M CoSO₄, 40 g/L H₃BO₃, 0.865 g/L SLS and 0.345 g/L β-naphthol. The current efficiency for alloy deposition was 50% in the current density range 0.5–2.5 A/dm². X-ray fluorescence studies on the alloy deposit formed on steel revealed 58–75% zinc on the surface. Anodic stripping voltammetric studies were carried out on zinc-cobalt alloy films formed on glassy carbon to identify the phases formed in the alloy. Zn-Co alloy film dissolution peaks suggested the existence of β, β₁ and γ phases of the alloy. Electronic Publication     

Mössbauer and XRD investigation of electrodeposited Fe,Co and Fe-Co alloys using a gluconate plating process

Summary A fundamental requirement for electrodeposition systems of the 21st century is that the processes involved should be environmentally safe, as well as they should be suited to replace hazardous conventional processes thereby supporting global sustainability. Conventional plating baths contain hazardous components and facilitate the generation of non-desirable compounds. The subject of the present article is the electrodeposition of Fe, Co, and Fe-Co alloys from an electrolyte based on gluconate. Preliminary studies showed that good quality iron-cobalt alloy coatings could be obtained on copper substrates from an environmentally acceptable gluconate plating system. The gluconate bath is inexpensive, non-toxic and easily disposed of. We report the successful deposition of Fe, Co and Fe-Co alloys from a modified gluconate based electrolyte which has not been used previously to deposit these materials. The effect of process parameters, such as current density, pH and deposition time were investigated using the gluconate electrolyte at a temperature of 60 °C and a pH of 7. The phase composition, crystal structure and magnetic anisotropy of the obtained alloy deposits are correlated with the applied process parameters. The structural analysis of the deposits is mainly based on ⁵⁷Fe CEMS and XRD measurements. α-Fe and Co-Fe were identified as dominant phases in Fe and Co/Fe deposits, respectively. The magnetic anisotropy of the Fe-containing deposits was found to correlate with the current density applied during deposition. The time of electrodeposition, at the same time, had little if any effect on the magnetic anisotropy of the obtained deposits. The mechanism and formation of the electrodeposits are discussed on the basis of the obtained results.     

Anomalous codeposition of cobalt and ruthenium from chloride–sulfate baths

Codeposition of Ru and Co was studied at room temperature and at 50 °C with various Ru³⁺ and Co²⁺ concentrations in the electrolyte. The codeposition of Co and Ru proved to be anomalous since no pure Ru could be obtained in the presence of Co²⁺ in the electrolyte, but a significant Co incorporation into the deposit was detected at potentials where the deposition of pure Co was not possible. The composition of the deposits varied monotonously with the change of the concentration ratio of Co²⁺ and Ru³⁺. The deposition of Ru was much hindered, and the current efficiency was a few percent only when the molar fraction of Co in the deposit was low. Continuous deposits could be obtained only when the molar fraction of Co in the deposit was at least 40 at.%. The deposit morphology was related to the molar fraction of Co in the deposit. The X-ray diffractograms are in conformity with a hexagonal close-packed alloy and indicate the formation of nanocrystalline deposits. Two-pulse plating did not lead to a multilayer but to a Co-rich alloy. Magnetoresistance of the samples decreased with increasing Ru content.     

Electrodeposition of nanocrystalline Ni–Cu alloy from environmentally friendly lactate bath

A new environmentally friendly electroplating bath for Ni–Cu alloy deposition was developed. Lactic acid was used as a complexing agent. The influence of bath composition, current density, pH and temperature on cathodic polarization, cathodic current efficiency and alloy composition was studied. Different proportions of the two metals were obtained by using different deposition parameters, but at all [Ni²⁺] / [Cu²⁺] ratios studied, preferential deposition of Cu occurred and regular co‐deposition took place. The Ni content of the deposit increased with Ni²⁺ content and current density and decreased with temperature. The surface morphology of the deposited Ni–Cu alloy was investigated using scanning electron microscopy. The crystal structure was examined using the X‐ray diffraction technique. The results showed that the deposits consisted of a single solid solution phase with a face‐centered cubic structure. The crystallite size lies in the range of 12 to 25 nm for as‐plated alloys. Copyright © 2014 John Wiley & Sons, Ltd.     

Electrodeposition of aluminum–hafnium alloy from the Lewis acidic aluminum chloride-1-ethyl-3-methylimidazolium chloride molten salt

The electrochemistry of Hf(IV) and the electrodeposition of Al–Hf alloys were examined in the Lewis acidic 66.7–33.3 mol% aluminum chloride-1-ethyl-3-methylimidazolium chloride molten salt containing HfCl₄. When cyclic staircase voltammetry was carried out at a platinum disk electrode in this melt, the deposition and stripping waves for Al shifted to negative and positive potentials, respectively, suggesting that aluminum stripping is more difficult due to the formation of Al–Hf alloys. Al–Hf alloy electrodeposits containing ~13 at.% Hf were obtained on Cu rotating wire and cylinder electrodes. The Hf content in the Al–Hf alloy deposits depended on the HfCl₄ concentration in the melt, the electrodeposition temperature, and the applied current density. The deposits were composed of dense crystals and were completely chloride-free. The chloride-induced pitting corrosion potential of the resulting Al–Hf alloys was approximately +0.30 V against pure aluminum when the Hf content was above 10 at.%.     

Morphology and composition of Ni–Co alloy powders electrodeposited from ammoniacal electrolyte

In this paper, the morphology and phase structure of Ni–Co powders electrodeposited from ammoniacal electrolyte are investigated as a function of alloy powder composition. Composition of the electrolyte, i.e. the ratio of Ni²⁺/Co²⁺ concentration is found to influence both, the phase structure and the morphology of Ni–Co alloy powders. It is shown that the current density practically does not influence the morphology of Ni–Co alloy powders as well as alloy powder composition. At the highest ratio of the Ni²⁺/Co²⁺ ions typical spongy particles were obtained. With the decrease of the Ni²⁺/Co²⁺ ions ratio agglomerates of the size of about 100 μm, composed of a large number of fern-like dendrites on their surface were obtained. At the lowest Ni²⁺/Co²⁺ concentration ratio, among more dendritic particles, agglomerates typical for pure Co powder deposition were detected. It is also shown that depending on the Ni²⁺/Co²⁺ ratio different types of Ni and Co codeposition could be detected: anomalous and irregular. At the Ni²⁺/Co²⁺ ions ratio higher than 1 only β-Ni phase was detected, while at concentration ratios Ni²⁺/Co²⁺<1 h.c.p. α-Co phase together with β-Ni phase was detected in the alloy powder deposit.     

Characteristic of hydrogen-saturated Pd-based alloys for the application in electrochemical capacitors

Hydrogen electrosorption was performed in thin electrodeposits of Pd alloys with Pt, Au, and Rh. The possibility of their application as phase charging–discharging systems was investigated. The values of specific pseudocapacitance, power, and energy were calculated for hydrogen-saturated Pd-rich electrodes for temperatures 283–313 K. The best working parameters are exhibited by Pd–Rh alloys with 85–95% Pd, and by Pd–Pt alloys with 90–95% Pd in the bulk. The maximum values of specific pseudocapacitance are ca. 4,500 F?g^?1, specific energy ca. 150 J?g^?1 and specific power up to 750 W?g^?1 (per the mass of the electroactive material). In the case of the alloy deposits on reticulated vitreous carbon, their characteristics related to the total mass of the electroactive material and the substrate are comparable with those for other supercapacitors utilizing various redox reactions.     

Effects of well-defined magnetic field gradients on the electrodeposition of copper and bismuth

Paramagnetic Cu²⁺-ions have been electrodeposited under application of magnetic field gradients. Obtained deposits show a direct correlation of the distribution of magnetic flux density B at the electrode and the deposit thickness and morphology. In contrast to that no influence on the deposit structure has been observed for deposition of Bi from electrolytes containing diamagnetic Bi³⁺-ions. This indicates that the structuring effect is mainly based on the action of the magnetic gradient force. A structuring-mechanism has been proposed that also discusses influences of the Lorentz force.