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1.
Tatsuko Takei 《Electrochimica acta》1980,25(10):1231-1237
This paper will deal with the electrodeposition of copper and nickel from the Cu(CF3COO)2-HCONH2 bath, Ni(CF3COO)2-HCONH2 bath, Cu(CF3COO)2-HCON(CH3)2 bath and Ni(CF3COO)2-HCON(CH3)2 bath. The properties of these baths and the mechanism of the electrodeposition of copper and nickel from these baths were studied. While solvolysis occurs in the HCONH2 bath, it does not occur in the HCON(CH3)2 bath. A complex is formed in each bath. Since the bond between the metallic ion and the solvent in the HCON(CH3)2 bath is stronger than that in the HCONH2 bath, and since the dielectric constant of the solvent in the former is also lower than in the latter, is difficult to electrodeposit metal and Cu2O is formed at cathode in the Cu(CF3COO)2-HCON(CH3)2 bath. The specific conductance in the HCON(CH3)2 bath is lower than that in the HCONH2 bath. It is possible to obtain a better copper electrodeposit over a wider range of current density in the Cu(CF3COO)2- HCON(CH3)2 bath containing citric acid than in the same bath containing no citric acid. This range almost coincides with that in the Cu(CF3COO)2-HCONH2 bath. While it is possible to obtain better nickel electrodeposit in Ni(CF3COO)2-HCONH2 and Ni(CF3COO)2-HCON(CH3)2 baths containing appropriate additives, the range of current density which permits one to obtain a superior electrodeposit in the latter bath is narrow. The electrodeposit of nickel or copper obtained from the HCONH2 and HCON(CH3)2 baths has a granular structure. The values of ηcEc, and bc in the copper electrodeposition reaction from the Cu(CF3COO)2-HCON(CH3)2-200 g/l citric acid bath are higher than those in the same reaction from the Cu(CF3COO)2-HCONH2 bath, while the values of ioc and αc are lower, so the electrodeposition of copper from the former can be said to be more difficult. On the other hand, the value of n is always about 1 for both the baths. It may be concluded in view of this fact that the deposition of copper from HCONH2 and HCON(CH3)2 baths takes place through Cu+ and that the deposition of nickel from HCONH2 bath takes place through Ni+. 相似文献
2.
R. FRATESI G. ROVENTI G. GIULIANI C. R. TOMACHUK 《Journal of Applied Electrochemistry》1997,27(9):1088-1094
Electrodeposition of Zn–Co alloys on iron substrate from chloride baths under galvanostatic and potentiostatic conditions were carried out. Current density, temperature and cobalt percentage in the bath were found to strongly influence the composition of the deposits and their morphology. Changes in potentials, current efficiency and partial current densities were studied. The results show that the shift in potential and in the cobalt percentage of the deposits, for a particular current density during galvanostatic electrodeposition, does not always correspond to the transition from normal to anomalous codeposition. This shift is attributed to zinc ion discharge, which passes from underpotential to thermodynamic conditions. In the range of potentials for the underpotential deposition of zinc, the electrodeposition of zinc–cobalt alloys is discussed, emphasizing the influence of the electrode potential on the composition and microstructure of the deposits. 相似文献
3.
The current efficiency of chromium electrodeposition and cathodic polarization curves were determined in halide-chromic acid-sulphuric acid systems. The composition of the cathodic films formed was determined by XPS and AES. The results show that sulphate is an effective catalyst for the deposition of bright chromium and that the current efficiency of the chromium deposition increases remarkably when F– and Cl– are added to the bath, and also that F– and Cl– participate in the formation of the films. The depth profile curves of the film show that halide is distributed in the inner layer of the film, and SO4
2– in the surface layer. It is deduced that F– and Cl– form a bridged complex, [CIII-X–-CrIII], in which electron transition is easily carried out. 相似文献
4.
Model of nickel electrodeposition from acidic medium 总被引:2,自引:0,他引:2
A step-wise computer model is presented for simultaneous deposition of nickel and nickel hydroxide in aqueous solutions. In acidic solutions ({pH} 1), the potentiostatic current-time transient response on glassy carbon or titanium was analysed with respect to nucleation and radial growth mechanism. pH changes influence the current-time response greatly. A marked maximum in the current transient appears for slightly acidic solutions ({pH} 4.5) and a consecutive decrease in the deposition current density at long times is obtained. This behaviour is attributed to early precipitation of nickel hydroxide due to a local pH increase at the cathode surface. 相似文献
5.
Process of cathodic deposition of nickel mainly from Ni(BF4)2 solution in DMSO has been investigated using various experimental techniques. It has been found that this process is complicated. The collected experimental data indicate that passivation of fresh cathodic layer of Ni by chemisorption of DMSO molecules takes place. By basing on the rde methods the values of αnm = 0.4 (± 0.05) and kfh = f(Ec) have been estimated. 相似文献
6.
The effect of temperature on nickel electrodeposition from a nickel sulfamate electrolyte has been investigated. All the experimental
points in a plot of nickel film thickness vs. current density collapse onto a single straight line irrespective of deposition
temperature. A relation derived from the Butler–Volmer equation is successful in predicting cathode potential shifts caused
by change of deposition temperature. Moreover, an interface width, which characterizes the roughness of the surface and is
defined by the root mean square of fluctuation in the height, is shown to have a saturated value that is related to the deposition
temperature. Thus, two kinds of activation energies for the charge transfer reaction and for grain growth are estimated from
the temperature dependence of the cathode potential shift and the grain size. 相似文献
7.
Constantin Claudiu Văduva Nicolae Vaszilcsin Andrea Kellenberger Mihai Medeleanu 《Journal of Applied Electrochemistry》2012,42(4):217-224
To improve the quality requirements for copper deposits, the influence of some inhibition agents added to the acidic copper
bath has been studied. Several aromatic nitrogen compounds have been tested as inhibition agents, such as aniline, N-methylaniline, N-ethylaniline, N,N-dimethylaniline (DMA), and N,N-diethylaniline (DEA). The electrochemical behavior of these organic additives and the most relevant aspects of the electrochemical
behavior of copper in acid solutions have been analyzed by cyclic voltammetry. At the same time, a correlation between voltammetric
data and molecular properties of protonated amines obtained by molecular modeling has been performed. The morphology of the
copper deposits obtained in the absence and presence of organic compounds has been studied by scanning electron microscopy.
An improvement of the roughness degree and crystallite size upon addition of aromatic amine has been found. Best results were
obtained for DMA and DEA working at room temperature (25 ± 0.1 °C) and 200 A m−2 current density, in 1 mol L−1 sulfuric acid solution with 50 g L−1 Cu2+. 相似文献
9.
Tin electrodeposition in its initial stages in acid sulfate/gluconate baths was studied with varying tin and gluconate concentrations using potential-controlled electrochemical techniques. The deposit morphology was observed by scanning electron microscopy (SEM). A comparison with tin electrodeposition from acid sulfate baths in the absence of gluconate was also carried out. Use of a highly acidic bath leads to nonuniform deposits, even in the presence of gluconate; at pH 4 deposits are uniform, brilliant and suitable for finishing applications. Tin crystallites have a well defined morphology which depends on bath agitation conditions. In the absence of agitation, the crystallites have the same tetragonal shape as in a sulfate bath without gluconate. 相似文献
10.
Magdy A. M. Ibrahim 《Journal of Applied Electrochemistry》2006,36(3):295-301
Black nickel coatings were electrodeposited on to steel substrates from a Watts bath containing potassium nitrate. The best
operating conditions necessary to produce smooth and highly adherent black nickel were found to be NiSO4 · 6H2O 0.63 M, NiCl2 · 6H2O 0.09 M, H3BO3 0.3 M and KNO3 0.2 M at pH of 4.6, i=0.5 A dm−2, T=25 °C and t=10 min. The modified Watts bath has a throwing power (TP) of 61%, which is higher than that reported, not only for nickel,
but also for many other metals electrodeposited from different baths. The potentiostatic current–time transients indicate
instantaneous nucleation. X-ray diffraction (XRD) analysis shows that the black nickel deposit is pure metallic nickel with
Ni(111) preferred orientation. 相似文献
11.
S.O. Moussa M.A.M. Ibrahim S.S. Abd El Rehim 《Journal of Applied Electrochemistry》2006,36(3):333-338
Induced electrodeposition of Ni–W alloys was carried out onto steel substrates from acidic citrate baths (pH 4.5) under different
conditions of concentration of electrolyte, current density and temperature. Bright and highly adherent Ni–W deposits were
successfully obtained with a relatively high cathodic current efficiency CCE (80–85%). The CCE increases greatly with increasing
pH and Ni2+ ion content in the bath. The W% in the alloy deposits is in the range of 4–20 wt% depending on the operating condition. The
W content in the deposit was found to increase with an increase in Ni2+ ion content, pH and temperature. The surface morphology was examined by scanning electron microscopy while the structure
of the alloy was examined by X-ray diffraction analysis. 相似文献
12.
The electrodeposition of copper, zinc and copper-zinc alloys from alkaline tartrate solutions has been investigated under different conditions of bath composition, added ammonium chloride, current density and temperature. A detailed study has been made of the effect of the variables on the cathode potentials and cathode efficiencies of copper, zinc and Cu-Zn alloys; the compositions of the alloys were determined. The results were consistent with the behaviour of a regular alloy plating system with zinc being the less noble metal. 相似文献
13.
The influence of sorbitol or glycerol on the electrodeposition of ZnNi alloys and on the morphology, composition and structure
of the ZnNi deposits was investigated. The highest current efficiency (CE), around 90%, was obtained in the presence of glycerol
in the potential range from approximately −1.30 V to −1.40 V, while in the presence of sorbitol or absence of either polyalcohol
the CE was 82–85%, for the same potential range. Scanning electron microscopy (SEM) analysis showed that ZnNi deposition at
−1.26 V or −1.40 V from a bath with sorbitol led to the formation of more compact deposits than with glycerol. Energy dispersive
X-ray spectroscopy (EDS) analysis showed that the Ni content in the deposit obtained in the presence of sorbitol remained
in the range of 7–9.5 wt% Ni, over a large range of deposition conditions. On the other hand, ZnNi deposits with variable
Ni content (5.5–19.5 wt% Ni) were obtained from baths with glycerol or without either polyalcohol, by shifting the deposition
potential. All ZnNi deposits showed uniform distribution of the elements Zn and Ni. X-ray analysis of ZnNi deposits obtained
from plating baths with and without polyalcohol’s at −1.26 and −1.40 V presented the γ, γ1 and Pt3–Zn phases. 相似文献
14.
Cyclic voltammetry and chronoamperometry at glassy carbon and platinum microdisc electrodes have been used to study the electrodeposition of Co–W amorphous alloys. Voltammetric results show that cathodic deposition of Co–W alloy is accompanied by hydrogen evolution and the efficiency of Co–W electrodeposition does not exceed 20%. Voltammetric behaviour of cobalt (II) and tungstate in ammonium citrate solution depend strongly on composition of the plating bath. The concentration of Co(II) ions can be monitoredin situ during electroplating by means of anodic stripping voltammetry at a platinum microelectrode. The deposit of the alloy on the microelectrode is stable in the atmosphere and thus can be stored for subsequent comparison with a deposit obtained later in the life of the working bath. 相似文献
15.
Surface pH measurements during nickel electrodeposition 总被引:3,自引:0,他引:3
J. Ji W. C. Cooper D. B. Dreisinger E. Peters 《Journal of Applied Electrochemistry》1995,25(7):642-650
To better understand the electrochemistry of nickel electrowinning from nickel chloride solutions at the cathode-electrolyte interface, the cathode surface pH was measured using a flat-bottom combination glass pH electrode and a 500 mesh nickel-plated gold gauze as cathode. The cell was a modification of that designed by Romankiw and coworkers. The pH electrode was positioned at the back of, and in direct contact with, the gauze cathode. As expected, the cathode surface pH was always higher than the pH in the bulk electrolyte, and if the current density was sufficiently large, it could cause the precipitation of insoluble Ni(OH)2(5) on the cathode surface. Lower bulk pH, higher nickel concentration, higher temperature, and the additions of H3BO3 and NH4Cl effectively suppressed the rise of the cathode surface pH. The results provide further evidence of the buffering action of H3BO3 and NH4Cl and of the enhancement of nickel deposition by H3BO3. At current densities less than 240 A m–2 additions of NaCl and Na2SO4 suppressed the rise of the cathode surface pH but to a much smaller degree. 相似文献
16.
Tatsuko Takei 《Electrochimica acta》1978,23(7):599-604
In the present study, the electrodepositions of copper from the Cu(CF3COO)2CF3COOHH2O bath and nickel from the Ni(CF3COO)2NH4ClH2O bath, were studied.In the copper electrodeposition from Cu(CF3COO)2 (100 g/l)CF3COOH(0.1 N)H2O bath, the cathode current efficiency showed about 100% and the anode current efficiency showed over 100% at low cd. In the nickel electrodeposition from Ni(CF3COO)2 (200 g/lH4Cl(15.0 g/l)H2O bath, the efficiencies of the cathode and anode were about 100%. The range of current density to obtain bright and smooth copper and nickel deposits were 4.0 ~ 24 A/dm2, 5.0 ~ 16 A/dm2 respectively, and the cross-section of the electrodeposits showed a granular structure.The rates of the electrodeposition of copper and nickel from the above-mentioned baths were controlled by the charge-transfer reaction in the same way as in the reaction in non-aqueous solution[1, 2]. 相似文献
17.
方波伏安法快速测定镀镍液中的镍含量 总被引:1,自引:0,他引:1
由于利用传统度镍液中的镍含量时共存离子的干扰不易消除,在此采用方波伏安法进行测定。阐述了该方法的原理,探讨了试验条件,共存离子对测量结果的影响。结果发现,在PH=10.0的NH3.HO2-NH4CI缓冲液中以三乙醇胺为掩蔽剂,镍(Ⅱ)于-1.12V(vsSCE)出现极谱峰,在镍(Ⅱ)浓度为2~20g/L范围内镍(Ⅱ)浓度成线性关,镍(Ⅱ)检出限为0.5mg/L。该方法简单、快速、准确度和灵敏度高, 相似文献
18.
分光光度法测定光亮镍及珍珠镍镀液中的镍含量 总被引:6,自引:0,他引:6
光亮镍和珍珠镍镀中镍的测定定通常采用EDTM滴定法,该法选择性低,易造成环境污染,本文采用分光光度法进行分析,探讨了测量波长,硫酸浓度及干扰元素等的影响,该法在镍含量为0-200mg范围内遵守比耳定律,测量结果准确,能满足实际生产的要求。 相似文献
19.
The kinetics of nickel-zinc co-deposition and the effect of nickel on zinc morphology have been studied by means of chemical analysis, X-ray diffraction and SEM observations of cathodic deposits obtained in various experimental conditions, including acid and alkaline baths. It has been shown that nickel ions, even if present in the electrolyte at very low concentrations (1 ppm), do not deposit under mass transport controlled conditions but are dragged by zinc ions whose concentration influences the nickel current. With regard to zinc morphology, it has been observed that nickel reduces the grain size of the zinc crystals formed during the electrodeposition. 相似文献