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1.
M. M. Kamel 《Journal of Applied Electrochemistry》2007,37(4):483-489
Thin films of cobalt–nickel alloys were galvanostatically deposited onto steel substrates from gluconate baths. Cathodic polarization
curves were determined for the parent metals and Co–Ni alloy. The effects of bath composition, current density and temperature
on cathodic current efficiency (CCE) and alloy composition were studied. The deposition of Co–Ni alloy is of anomalous type,
in which the less noble metal (Co) is preferentially deposited. The CCE of codeposition is high and increases with increase
in temperature and current density, but it decreases as the [Co2+]/[Ni2+] ratio in the bath increases. The percentage of Co in the deposit increases with increasing cathodic current density, temperature
and increasing Co2+ ion concentration. The structure and surface morphology of the deposit were studied by XRD, ALSV and SEM. The results showed
that the alloys consisted of a single solid solution phase with a hexagonal close packed structure. 相似文献
2.
Ferromagnetic Ni–Cr and Co–Cr alloy thin films were electrodeposited from aqueous solution containing trivalent chromium (Cr3+) ions and glycine. According to the Tafel slopes obtained from the cathode polarization curves for Ni–Cr and Co–Cr alloy deposition, it was estimated that Cr3+ ions inhibited Ni2+ and Co2+ ions from electrodepositing. Ni and Co preferentially electrodeposited rather than Cr and the electrodeposition process of Ni–Cr and Co–Cr was categorized to “normal co-deposition type.” At the cathode potential of −1.8 V versus Ag/AgCl/KCl sat., Ni—9.5 %Cr and Co—8.4 %Cr alloy deposits were obtained. X-ray diffraction patterns of the electrodeposits revealed that pure Ni and pure Co consist of large crystal grains, while Ni—9.5 %Cr and Co—8.4 %Cr alloys were composed of a solid solution phase with fine crystal grains. Magnetization of Ni—9.5 %Cr and Co—8.4 %Cr alloy thin films with fine crystalline phase reached to saturation at ca. 2.5 kOe in perpendicular direction to the film plane, while pure Ni and pure Co thin film with large crystal grains were hardly magnetized in the perpendicular direction. Soft magnetic properties were improved with increasing Cr content in the deposits. 相似文献
3.
R. A. C. Santana S. Prasad A. R. N. Campos F. O. Araújo G. P. da Silva P. de Lima-Neto 《Journal of Applied Electrochemistry》2006,36(1):105-113
Electrodeposition of Ni–W–B alloys from plating baths containing ammonia and citrate is reported. Optimum conditions for plating
including current density, temperature, mechanical agitation and pH were studied. The corrosion resistance and amorphous character
were also evaluated. The operational conditions for depositing the alloy with good corrosion resistance were: current density
35 mA cm−2, bath temperature 40 °C, pH 9.0 and cathode rotation at 90 rpm. The alloy was deposited at 38% current efficiency, with an
average composition of 73 wt% Ni, 27 wt% W and traces of boron and with E
corr −0.300 V and R
p 3.369×104 Ω. The deposit obtained under these conditions had an amorphous character with the presence of some microcracks on its surface
reaching down to the copper substrate. Electrochemical corrosion tests verified that the Ni–W–B alloy had better corrosion
resistance than Co–W–B. 相似文献
4.
Electroless nickel–phosphorus (Ni–P) deposition provides coatings with high hardness and excellent resistance to wear and
abrasion. In this study, autocatalytic deposition of Ni–P alloy has been carried out on steel CK-75 sheets from bath containing
nickel sulfate hexahydrate, sodium hypophosphite hydrate, thiourea, lactic acid, and sodium acetate. The effects of lactic
acid concentration, pH and temperature on deposition rate, composition of deposits, and hardness have been studied. Also the
changes in the hardness and structure of deposits by heat-treatment were studied by X-ray diffraction and scanning electron
microscopy methods. It is shown that deposits crystallized after heat-treatment at 400°C for 1 h and crystallization to Ni
and Ni3P was observed. 相似文献
5.
M. M. Abou-Krisha F. H. Assaf S. A. El-Naby 《Journal of Coatings Technology and Research》2009,6(3):391-399
The present work is directed at collecting the properties of Zn–Ni and Zn–Fe alloys in one alloy via the electrodeposition
of Zn–Ni–Fe ternary alloy. Electrodeposition of ternary Zn–Ni–Fe alloy was investigated and compared with the characteristics
of Zn–Ni electrodeposits. The electrodeposition was performed from a sulfate bath onto a steel substrate. Structural analysis
by X-ray diffraction (XRD) method revealed that the Zn–Ni–Fe alloys consisted of a mixture of zinc, and (γ-Ni2Zn11) and (Fe3Ni2) phases. The study was carried out using electrochemical methods such as cyclic voltammetry and galvanostatic for electrodeposition,
while anodic linear polarization resistance and anodic linear sweeping voltammetry techniques were used for the corrosion
study. Surface morphology and chemical composition of the deposits were also examined by using scanning electron microscopy
and atomic absorption spectroscopy, respectively. It was found that the obtained Zn–Ni–Fe alloy exhibited more preferred surface
appearance and better corrosion resistance without adding any organic brighteners to the plating bath in comparison to Zn–Ni
alloy that electrodeposited at similar conditions. Results obtained revealed that the increase in corrosion resistance of
ternary deposits is not only attributed to the formation of (γ-Ni2Zn11) phase, but also to iron codeposition and formation of (Fe3Ni2) phase. 相似文献
6.
M. Zemanová M. Krivosudská M. Chovancová V. Jorík 《Journal of Applied Electrochemistry》2011,41(9):1077-1085
Ni–W alloy coatings were prepared on a mild steel substrate by means of pulse current (PC) and compared to the coatings electrodeposited
by direct current (DC). In particular the study dealt with the influence of the frequency using pulse current on the surface
morphology while maintaining a constant duty cycle. A constant charge for DC and PC electrodeposition of Ni–W alloy coatings
was used. The morphology of the coatings was explored by scanning electron microscopy and the composition of the coatings
was analysed by X-ray powder diffraction and energy dispersive X-ray analysis. Corrosion resistance of Ni–W alloy coatings
was investigated by potentiodynamic polarization in a chloride medium. The corrosion products were analysed by Raman spectroscopy.
It was found that the temperature of the electrolysis affects current efficiency of the DC and PC electrodeposition. The frequency
of pulse electrodeposition alters the morphology of the Ni–W alloy coatings. There was evidence of the positive influence
of increased tungstate concentration in the electrolyte on corrosion resistance of the Ni–W alloy coatings. 相似文献
7.
Wenfeng Qin 《Journal of Coatings Technology and Research》2011,8(1):135-139
The microstructure and corrosion behavior of electroless Ni–P alloy plating on 6061 aluminum alloys substrate in an alkaline
plating bath with sodium hypophosphite as reducing agent were investigated. The effects of bath temperature on the plating
rate, compositions, and microstructure of the electroless Ni–P deposits were studied. The results showed that the deposition
rate and the P content of the electroless Ni–P deposits increased with the rise of the bath temperature. Scanning electron
microscopy (SEM) of the deposits showed nodular structure for binary deposits. X-ray diffraction patterns of all the deposits
revealed a single and broad peak which indicated the amorphous structure of the deposits. Corrosion resistance of the Ni–P
coatings was evaluated by potentiodynamic polarization. The results indicated that electroless Ni–P plating could obviously
improve the corrosion resistance of 6061 aluminum alloy. 相似文献
8.
Meenu Srivastava V. K. William Grips K. S. Rajam 《Journal of Applied Electrochemistry》2010,40(4):777-782
The effect of alloying <1 wt% Mn with plain Ni, Ni–Co alloys and plain Co coatings in terms of the structure and properties
has been studied. The alloys were electrodeposited from an additive free sulphamate electrolyte. The Mn concentration in the
electrolyte was maintained at 5 g L−1 so as to obtain <1 wt% Mn content in the alloy coatings. The Energy Dispersive X-ray analysis (EDX) showed that the Mn content
reduced from 0.97 to 0.05 wt% with increase in Co content from 0 to 98 wt% in the alloy coating. An increase in microhardness
was obtained on the addition of Mn to Ni/Ni–Co alloys. The X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM)
studies revealed a change in crystal structure and morphology. Pin-on-disc tribology test revealed better wear performance
of Ni–18 wt%Co–Mn alloy coating compared to the other Ni–Mn/Ni–Co–Mn alloy coatings. 相似文献
9.
Lijian Xu Jingjing Du Shuxun Ge Nongyue He Song Li 《Journal of Applied Electrochemistry》2009,39(5):713-717
Fe–Ni–Cr alloy layers were prepared by electrodeposition from trivalent chromium plating bath in chloride-sulfate based solution.
The influences of bath composition and plating parameters on the alloy electrodeposition process and the properties of deposited
alloy were studied. The effects of plating parameters and bath composition such as current density, bath pH, bath temperature,
the concentrations of FeSO4 · 7H2O and CrCl3 · 6H2O on the contents of Fe and Cr in Fe–Ni–Cr alloy layer were investigated. Electrodeposited Fe–Ni–Cr alloy layers on Fe substrate
were characterized by X-ray diffraction (XRD), Electronic Differential System (EDS) and a CHI600B electrochemistry workstation.
The composition of the Fe–Ni–Cr coatings depends on bath composition and plating conditions including pH, current density,
and temperature. The internal structure of the alloy is nanocrystalline, the average grain size is 87 nm, and the corrosion
resistance of the alloy layers is better than that of pure nickel layers. 相似文献
10.
Abdel Salam Hamdy M. A. Shoeib H. Hady O. F. Abdel Salam 《Journal of Applied Electrochemistry》2008,38(3):385-394
The performance of ternary electroless deposited Ni–P–W and Ni–P–alumina composite coatings on low carbon steel substrates
was studied. The effect of experimental parameters, such as temperature, pH, nickel sulfate concentration, sodium hypophosphite
concentration, sodium citrate concentration, and deposition time on the deposition rate were investigated. The coating brightness,
coherence, and uniform surface distribution were improved due to addition of W and alumina. The coating performance was evaluated
based on the wear-resistance, micro-hardness, and corrosion resistance. The Ni–P–W ternary alloy coatings showed the highest
micro hardness, wear-resistance, brightness, and corrosion resistance. The improvement in the performance of Ni–P–W coatings
can be explained by the formation of a tungsten phosphide phase. 相似文献
11.
R. H. Guo S. Q. Jiang C. W. M. Yuen M. C. F. Ng 《Journal of Applied Electrochemistry》2009,39(6):907-912
The copper content of electroless Ni–Cu–P-plated polyester fabric mainly depends on the copper ion concentration in the plating
solution, which in turn has a significant effect on the properties of the coatings. The effects of copper sulphate concentration
(CuSO4) on the deposition rate, composition, surface morphology, crystal structure, surface resistance and electromagnetic interference
(EMI) shielding effectiveness of electroless Ni–Cu–P deposits were investigated. The results show that the copper content
in the deposits increased significantly, whereas nickel content decreased significantly and phosphorus content decreased slightly
with a higher copper ion concentration. Compact coating layers were obtained with a nodular morphology. With increase of copper
ion concentration in the solution, the crystallinity of the deposits also increased. In addition, the surface resistance decreased
and the EMI shielding effectiveness of the Ni–Cu–P deposits increased. 相似文献
12.
An Ni-Mn-Zn alloy has been satisfactorily electrodeposited from a sulphate bath containing nickel sulphate (20–23 g dm−3), manganese sulphate (76–88 g dm−3), zinc sulphate (18–24 g dm−3), ammonium sulphate (30 g dm−3), thiourea (18g dm−3) and ascorbic acid (0.8 g dm−3) under various plating conditions, namely, current density 1.0–3.0 A dm−2; temperature 30–45° C; pH 2.7–4.2 and duration of electrolysis 15–30 min. Semibright, blackish-grey, thin films were generally
deposited with the proportion of nickel and manganese in the deposits increasing with increasing current density, temperature
and duration of electrolysis. However, the amount of zinc increased as the pH of the solution was raised. The cathode efficiency
for alloy deposition increased linearly as the temperature or the pH of the solution was decreased, whereas at any particular
pH and temperature it continuously rose with increasing current density or the time of deposition. The cathode polarization
shifted to more negative values on increasing the current density and to less negative values at higher pH values and temperatures
which consequently lowered the throwing power under the latter conditions. 相似文献
13.
The electroless deposition of Ni–W–P alloy coatings onto metal substrates using H2PO2
– as reducing agent from solutions containing nickel sulfate, sodium tungstate, sodium citrate, ammonium sulfate and other additives was studied. At most temperatures (60–80 °C) and pHs (7–11) investigated, bright and coherent coatings uniform in appearance were produced. Phosphorous and tungsten contents ranging from 3.5 to 8 wt % and 0.5 to 6 wt %, respectively, were obtained depending upon solution temperature and pH. Trends such as the effects of pH and temperature on average metal deposition rate and the P content in the alloy are similar to that reported previously for the Ni–P system. Correlation of open-circuit potentials with events occurring at the electrode surface in different solutions and polarization curves provide strong evidence that Ni2+ ions participate in W and P deposition, H2 evolution and H2PO2
– oxidation and that H2PO2
– ions participate in cathodic reduction. This indicates that the partial reactions for the Ni–W–P system do not occur independently of one another. 相似文献
14.
R. H. Guo S. Q. Jiang C. W. M. Yuen M. C. F. Ng G. H. Zheng 《Journal of Coatings Technology and Research》2012,9(2):171-176
Properties of electroless Ni–P plated polyester fabric mainly depend on the plating bath constituents/conditions. The effects
of NiSO4 concentration of the plating bath on the deposition rate, phosphorus content, surface morphology, and crystal structure of
the electroless Ni–P plated polyester fabric were investigated. The study revealed that phosphorus content in the deposits
decreased at higher NiSO4 concentration. SEM micrographs showed that nodule size of the Ni–P deposits increased. All the Ni–P deposits had an amorphous
structure. The electromagnetic interference (EMI) shielding effectiveness (SE) of electroless Ni–P plated polyester fabric
was evaluated. With the rise of nickel ion in the solution, the EMI SE of the Ni–P plated polyester fabric increased. 相似文献
15.
To reduce irreversible capacity and improve cycle performance of tin used in lithium ion batteries, Sn–Ni alloy nanorod electrodes with different Sn/Ni ratios were prepared by an anodic aluminum oxide template-assisted electrodeposition method. The structural and electrochemical performance of the electrode were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, cyclic voltammetry, and galvanostatic charge–discharge cycling measurement. The results showed that the copper substrate is covered with uniformly distributed Sn–Ni alloy nanorods with an average diameter of 250 nm. Different phases (Sn, Ni3Sn4 and metastable phases) of alloy nanorod formed in the electrodeposition baths with different compositions of Sn2+ and Ni2+ ions. Sn–Ni alloy nanorod electrode delivered excellent capacity retention and rate performance. 相似文献
16.
M.M.V. Parente O.R. Mattos S.L. Díaz P. Lima Neto F.J. Fabri Miranda 《Journal of Applied Electrochemistry》2001,31(6):677-683
Ni–P and Ni–Co–P amorphous alloy deposits were obtained by electrodeposition at 80 °C on carbon steel substrates. The influence of the electrolyte Co2+ concentration and of applied current density was investigated. The corrosion behaviour of amorphous and crystalline deposits was evaluated by polarization curves and electrochemical impedance spectroscopy in NaCl 0.1 M solution at room temperature. Impedances were measured for samples under total immersion (free potential against time) and for polarized samples in predefined regions of the polarization curves. It was found that the alloy deposit composition is highly affected by the composition of the electrolyte but displays no significant dependence on applied current density. The results showed that the presence of Co on Ni–P amorphous alloys improves the deposit performance in the studied corrosive medium. It was also verified that the amorphous structure provides higher corrosion resistance to both Ni–P and Ni–Co–P alloys. 相似文献
17.
Ternary zinc–nickel–cobalt alloys were electrodeposited on steel substrates from sulfate bath by direct current. Microstructural
and mechanical properties of Zn–Ni–Co ternary alloy coatings were investigated and contrasted with the characteristics of
Zn–Ni and Zn–Co alloy coatings. It was found that the obtained Zn–Ni–Co alloy exhibited more preferred surface morphology
and mechanical properties as compared to the other alloy coatings electroplated at the same conditions. X-ray diffraction
studies showed that the deposits of Zn–Ni–Co alloy coatings consisted of Zn, ZnNi3, and ZnCo13 phases. The structure, surface morphology, and surface topography of the deposited alloys were characterized by X-ray diffraction
(XRD), scanning electron microscopy (SEM) with energy dispersive X-ray microanalysis (EDS), and atomic force microscopy (AFM).
In addition, hardness, elasticity modulus, and adhesion strength of coated alloys were measured with dynamic ultra-microhardness
(DUH) and Scratch tester. 相似文献
18.
To improve the mechanical properties of electrodeposited copper, a new bath was developed for the codeposition of copper and
platinum. A pyrophosphate bath employing chloroplatinic acid as a source of platinum was investigated at current densities
ranging from 1 to 4 A dm−2 and temperatures from 20 to 60 °C. Bright, shiny and crack-free deposits were obtained at low current densities (i.e., 1–2
A dm−2). The amount of platinum observed in the deposits was found to increase with the current density and bath temperature. The
Knoop hardness was found to increase with platinum content in the deposits. Corrosion rates measured in solutions of NaCl
were found to decrease with platinum content. Deposits containing up to 3.9 wt % of platinum can be obtained by electrodeposition.
As compared to electrodeposited copper from the acid bath, the Cu—Pt deposits exhibited a 17% increase in Knoop hardness and
a 21% increase in corrosion resistance. 相似文献
19.
The electrodeposition of ternary Zn–Ni–Fe alloy films was investigated in acidic chloride electrolyte. Electrodeposition was performed onto mild steel plates at pH 3 and 43°C. The influence of the chloride concentration (ZnCl2, NiCl2 and FeCl2) on the surface appearance and deposit composition, as well as cathodic current efficiency, were investigated. Bright Zn–Ni–Fe alloy deposits were obtained in the electrolyte containing 0.4m of each of ZnCl2 and NiCl2 with 0.02 to 0.08m FeCl2. The influence of current density, pH and temperature were also examined. 相似文献
20.
The novel catalyst Ni–Cu alloys supported on carbon nanotubes (CNTs) was prepared by reduction with formaldehyde and applied
in steam reforming of methanol. With nitric acid and sulfuric acid to create defects on the surface of CNTs and using ethanol
to improve the hydrophilicity of CNTs, the Ni–Cu alloys were anchored on the surface of CNTs by co-reduction of Ni- and Cu-precursors
under the use of tetra-n-methylammonium hydroxide to reduce the aggregation of Ni–Cu particles. In contrast, Ni–Cu catalyst
supported on activated carbon (Ni–Cu/C) was prepared as well, and the bimetal of Ni and Cu supported on CNTs (Ni/Cu/CNTs)
was attained by successive reduction of first Cu- and then Ni-precursors. The catalysts were characterized with XRD, ED, FESEM,
transmission electron microscopy, and Thermogravimetric analysis. The hydrogen yield in steam reforming of methanol was near
100% at 360 °C over 20 wt.% Ni20–Cu80/CNTs. The catalytic activity of Ni20–Cu80/CNTs is much higher than that of Ni20–Cu80/C and Ni20/Cu80/CNTs. 相似文献