Statistical studies of Zn–Ni alloy coatings using Non-cyanide alkaline baths containing polyethyleneimine complexing agents

2014 ◽  
Vol 92 (5) ◽  
pp. 245-252 ◽  
Author(s):  
K. Ramazan ◽  
Y. Uğur
2014 ◽  
Vol 21 (01) ◽  
pp. 1450009
Author(s):  
MINGGANG LI ◽  
GUOYING WEI ◽  
JIANFANG WANG ◽  
MENG LI ◽  
XIXI ZHAO ◽  
...  

Non-cyanide alkaline bath was used to prepare copper thin films. Influences of various temperatures on deposition rates, surface morphologies and microstructures of films were investigated. Copper thin films prepared from non-cyanide alkaline bath show typical nodular structures. Copper films fabricated at higher temperature possess rough surface due to hydrolysis of complexing agents. According to the XRD patterns, all deposited films were crystalline and showed Cu (111), Cu (200) and Cu (220) peaks. The intensity of peak (200) increases gradually with the rise on bath temperatures. Films with maximum thickness (7.5 μm) could be obtained at the temperature of 40°C. From the cyclic voltammetry curve, it was found that the cathodic polarization decreased slightly with increase of bath temperatures. In addition, when the bath temperature was equal to 50°C, current efficiency could reach to 96.95%.


2006 ◽  
Vol 514-516 ◽  
pp. 88-92 ◽  
Author(s):  
Sergey K. Poznyak ◽  
Vladislav V. Kharton ◽  
Jorge R. Frade ◽  
Mário G.S. Ferreira

Several alkaline baths based on different complexing agents were examined for iron electroplating. The resultant films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was shown that adherent and smooth iron coatings with uniform microstructure can be obtained using alkaline Fe (II) baths containing pyrophosphate and tartrate ions as complexing agents. The average grain size can be substantially decreased by glycine additions in the pyrophosphate bath. The faradaic efficiency in these electrolytes may achieve up to 40-50%. The tartrate-containing baths are characterized with a higher throwing power and an increased buffer capacity with respect to the pyrophosphate-based electrolytes. The resultant Fe coatings are single-phase, whilst substantial broadening of the XRD peaks indicates nano-scale grain size. The alkaline baths based on EDTA complexes of iron (III) give black dull iron deposits and are characterized by rather low cathodic current efficiencies, especially at low current densities.


2013 ◽  
Vol 738 ◽  
pp. 87-91 ◽  
Author(s):  
Jin Ming Long ◽  
Xiu Zhang ◽  
He Zhong Pei

Zn-Ni alloy coatings were electrodeposited on low carbon steel substrate using a cyanide-free alkaline bath containing tetraethylenepentamine (TEPA) and triethanolamine (TEA) as complexing agents for Ni2+cations. Effect of TEA/Ni2+molar ratio on electrodeposition behavior, micromophology, Ni content and corrosion resistance of coatings were studied by means of SEM/EDS, polarization curve and electrochemical impedance spectroscopy (EIS), respectively. It was found that the deposition potential and elecctrochemical impedance of the cathode sample during the electrodeposition was influenced by the TEA/Ni2+molar ratio (TNmr) in the bath. The deposition potential shifts negatively and the impedance rises with increasing TNmrup to 2. The nickel content in Zn-Ni deposit was varied in a range from 16.81 to 19.04 wt.%. The dependence of cathodic current efficiency and depositing velocity of the coating on TNmrof plating bath were also determined. A fine-grained and smooth-faced coating was obtained at TNmr=2, which exhibited the highest corrosion resistance in 3.5% NaCl environment.


2014 ◽  
Vol 44 (1) ◽  
pp. 51-56 ◽  
Author(s):  
M. Moniruzzaman ◽  
K.M. Shorowordi ◽  
A. Azam ◽  
M.F.N. Taufique

Iron-nickel (Fe-Ni) alloy electrodeposition has been conducted from simple and complex baths having Ni/Fe ratio of 1 and 12. The applied current density varies from 30 to 100 mA/cm2. The coating composition, morphology and microhardness are measured and characterized by SEM/EDX and Shimadzu microhardness tester. The percentage of Ni in the coating increases with increasing current density and the Ni/Fe ratio of electrolytes which is supported by the alloy deposition principle. Fine grained and smooth coating without microcracking is obtained from the complex baths. Complexing agents are supposed to reduce the deposit stress developed during electrodeposition. Increase in Ni/Fe ratio in the bath as well as current density results in decreasing grain size of the deposits. High current density is believed to give rise to a high degree of adatoms at the electrode surface and high degree of adatoms decreases the grain size. Microhardness of the coating increases with the increase of bath Ni/Fe ratio as well as current density of electrodeposition. DOI: http://dx.doi.org/10.3329/jme.v44i1.19498


2002 ◽  
Vol 4 ◽  
pp. 375-375
Author(s):  
T. T. Takeuchi ◽  
T. T. Ishii ◽  
T. Totani

1965 ◽  
Vol 04 (03) ◽  
pp. 136-140
Author(s):  
Cl Jeanty

A method is described in an attempt to make medical records suitable for epidemiologigri: purposes. Every case of a disease is recorded on an appropriate punched card with the object of working towards a general description of a disease through the collation of several cases of the same diagnosis. This punched card represents a very great condensation of the original record. Special care has been applied to state as precisely as possible the time variable, particularly as far as its origin and unit of measure are concerned, in order to demonstrate the existence of causal relations between diseases. Such cards are also intended to make easier statistical studies in clinical pathology, in evaluation of new laboratory techniques, and in therapeutical trials.


2014 ◽  
Vol 29 (12) ◽  
pp. 1241
Author(s):  
ZHANG Guo-Fang ◽  
ZHANG Yang-Huan ◽  
LIU Zhuo-Cheng ◽  
XU Jian-Yi ◽  
ZHANG Yin

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