Complexing agent study <i>via</i> computational chemistry for environmentally friendly silver electrodeposition and the application of a silver deposit

Surface and Coatings Technology

et al. 2015

Self Cite

Section: Cyclic Voltammetrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrodeposition of nanocrystalline Zn–Ni coatings with single gamma phase from an alkaline bath

Surface and Coatings Technology

et al. 2015

Self Cite

“…The peaks c1 and a3 also appear in Zn only and Ni only bath. The literature 15 has revealed that DMH is easy to adsorb on electrode surface. This indicates that c1 and a3 are related to the adsorption and desorption of DMH on Pt electrode, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Our research group has successfully used 5,5 -dimethylhydantoin (DMH) as the main complexing agent to electrodeposit Au, 14 Ag, 15 and Cu 16 in alkaline non-cyanide bath. According to their results, it can be concluded that DMH mainly has two different roles in metal electrodeposition.…”

mentioning

confidence: 99%

Electrochemical Behaviors and Properties of Zn-Ni Alloys Obtained from Alkaline Non-Cyanide Bath Using 5,5^′-Dimethylhydantoin as Complexing Agent

et al. 2015

J. Electrochem. Soc.

Self Cite

Zn-Ni alloys were prepared in an alkaline bath with 5,5 -dimethylhydantoin (DMH) and Na 4 P 2 O 7 · 10H 2 O as the complexing agents. The electrochemical behaviors of Zn-Ni alloy and Zn only on Pt and glassy carbon (GC) electrodes were investigated by cyclic voltammetry (CV), chromoamperometry (CA) and cathode polarization. Results show that DMH is the main complexing agent in the bath. Different behaviors of CV curves on Pt and GC electrodes were observed. The effects of Ni 2+ /Zn 2+ ratio and bath temperature on CV curves were investigated. The transfer coefficient (α) and diffusion coefficient (D) were also calculated. The nucleation growth processes of Zn-Ni alloy and Zn only show an agreement with three-dimensional progressive growth. Zn-Ni alloy coatings were also characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The morphology of deposits is rectangular pyramid. The grain size decreases with the extension of the electrodepositing time and the decrease in the deposition potential can also lead to the decrease of grain size in deposits. The phase structure changes from the mixture of η and γ phases to single γ phase with (411) Zn-Ni alloy coatings are widely used to provide good protection for steel as replacements for Cd coatings in anticorrosion applications. 1,2They also have attracted great interests in relatively aggressive environment, i.e. high temperatures and severe oxidizing conditions.3 It has been reported that the processes of Zn-Ni alloy deposition can be divided into two types, the acid type and alkaline type. Most of Zn-Ni alloys are electrodeposited from the acid bath, 4,5 which displays a higher current density but poor distribution of the plated metal. However, the commercial alkaline bath used for Zn-Ni alloy deposition contains cyanide, which is toxic and carcinogenic to human health. In recent years, many attempts were done to investigate the alkaline non-cyanide bath and a number of complexing agents, such as tartrate, 6 sodium acetate, 7,8 amine, 9 triethanolamine, 10 glycinate, 11,12 ethylenediamine, 13 citrate and urea have been proposed. Among them, most of the complexing agents are used to complex Ni 2+ in the alkaline zincate bath which has a relatively low current efficiency and few effects have focused on investigating the alkaline non-zincate electrolyte due to its poor stability. Therefore, it is very urgent to find an alkaline non-zincate bath with high current efficiency and good stability to replace the cyanide bath.It is expensive and time-consuming to study a new complexing agent. Our research group has successfully used 5,5 -dimethylhydantoin (DMH) as the main complexing agent to electrodeposit Au, 14 Ag, 15 and Cu 16 in alkaline non-cyanide bath. According to their results, it can be concluded that DMH mainly has two different roles in metal electrodeposition. One is to complex the metal ions and the other is to adsorb on surface of the cathode. It is pos...

show abstract

“…The bright Zn-Ni 3 relatively low current efficiency, leaving it impossible for commercial use. 49 5,5'-dimethylhydantoin (DMH) has been successfully used in Au, 17 Ag 18 and Cu 19 50 electrodeposition and it is a promising complexing agent in Zn-Ni alloy deposition 51 owing to the large stability constants of DMH with Zn 2+ and Ni 2+ . 20 According to our 52 previous studies, 6,21 the investigated new alkaline Zn-Ni alloy bath has a high 53 stability and the aged baths have little effect on the electrochemical behaviors of the 54 investigated electrolyte.…”

Section: Introductionmentioning

confidence: 99%

Studies on the enhanced properties of nanocrystalline Zn–Ni coatings from a new alkaline bath due to electrolyte additives

et al. 2015

RSC Adv.

Self Cite