Influence Of Electrodeposition Potential Research Articles

The influence of electrodeposition potential on the chemical composition, structure and magnetic properties of FeCoNi nanowires

FeCoNi alloyed nanowires with diameters of 40 nm and 100 nm and a length of 6 µm were electrodeposited in the polycarbonate membranes at constant cathodic potentials ranging from −1.0 to −1.8 V. The increase in cathodic potential caused an increase in Ni content with a simultaneous decrease in Fe and Co concentrations. The samples showed an fcc structure (with a small hcp fraction observed in one sample) with a preferred growth along [111] direction, which changed to a [220] texture at higher deposition potentials. With the increase in Ni content, a shortening of the lattice parameters and an increase in the crystallite size were observed. Various chemical compositions resulted in the modification of the magnetic properties of nanowires. The magnetization saturation value increased with increasing cathodic potential for both types of nanowires. However, coercivity and squareness rose for samples with a diameter of 40 nm and fell down for 100 nm diameter nanowires. This specific behavior was explained based on dipolar interactions, which can be neglected in 40 nm diameter nanowires, due to the low membrane porosity.

Influence of electrodeposition potential, TiO2 nanoparticles and chromium (III) inhibitor addition on the corrosion protection performance of organosilane coating on aluminium

ABSTRACTIn this work, the anticorrosion properties of phenyl trimethoxysilane (PTMS) films coated on aluminium 5000 series alloys were studied. PTMS films were deposited at various cathodic potentials. The optimum electrodeposition potential was found to be −0.8 V vs. SCE. The coatings were also modified by different amounts of nano-TiO2. In order to introduce corrosion inhibition and a self-repair property of the PTMS film, the addition of chromium (III) corrosion inhibitor in the presence of nano-TiO2 was studied. The anticorrosion performance of coatings was investigated in a 3.5 wt.% NaCl solution. At optimum deposition potential, the ‘critical’ nano-TiO2 and Cr(III) contents were both observed, under which the obtained PTMS coatings show the highest anticorrosion performance. The surface morphologies of PTMS coatings were examined by scanning electron microscopy. The results showed that the coatings deposited at −0.8 V vs. SCE, from 20 ppm of nano-TiO2 and 0.003 M Cr(III) inhibitor present uniform and compact morphologies.

Influence of electrodeposition potential on composition and ion exchange of polypyrrole films in aqueous hexafluoroaluminate featured by EQCM molar mass to charge factors

EQCM gravimetry in a (10−8,10−6) g range was used for measurements of time processes of the potentiostatic deposition and redox state switching of polypyrrole in aqueous sodium hexafluoroaluminate. Time/potential dependencies of molar mass to charge factors determined from EQCM chronoamperometry and EQCM cyclic voltammetry were considered to reveal how the electrodeposition potential affects composition and ion-exchange properties of the resulting polymer film. Polypyrrole was synthesized at constant potentials, from +0.55V to +0.80V vs. SCE. The redox switching and accompanying ion-exchange were monitored in (+0.6,−0.6)V and (+0.6,−1.2)V vs. SCE potential windows.A lower mean chain length (polymerization degree) and a higher contribution of sodium in the mixed ion-exchange processes can be postulated for the thin polypyrrole deposit when it involves a higher content of the 2D chain packing structure. The distinct behavior corresponds to polypyrrole electropolymerized at the slowest rate, i.e. at +0.55V vs. SCE, which is know to result in the highest content of the 2D packing structure in the deposited film and the lowest mean reversible oxidation degree of the polymer.The molar mass to charge factor of EQCM gravimetry is useful for comparative studies of the rate processes involving electrolyte and electrode species, facilitating for their chemical identification.

Template Assisted Electrochemical Growth of Cobalt Nanowires: Influence of Deposition Conditions on Structural, Optical and Magnetic Properties

The influence of electrodeposition potential, pH, composition and temperature of the electrolytic bath on the structure of cobalt nanowires arrays electrodeposited into anodic aluminum oxide (AAO) porous membranes is reported. XRD, SEM, and TEM analysis were employed to characterize structural (crystal phase, crystallographic texture, and grain size), and morphological nanowire properties. It was confirmed that at pH 2 the electrodeposition potential has not influence on the preferred crystallographic orientation of the electrochemically grown Co nanowires. At pH 4 the electrodeposition potential controls the growth of cobalt nanowires along some preferential crystallographic planes. The electrolytic pH bath modulates the fcc or hcp phase exhibited by the cobalt nanowires. Single crystalline nanowires with a hcp phase strongly oriented along the (2021) crystallographic plane were obtained at pH 4 and at -1.1 V (vs. Ag/AgCl), a result not previously reported. High electrolytic bath temperatures contributed to improve the single crystalline character of the cobalt nanowires. The presence of chloride anion in the electrolytic bath also influenced on the structural properties of the resulting cobalt nanowires, improving their crystallinity. The optical reflectance of the samples shows a structure in the UV-blue region that can be assigned to the two-dimensional morphology arising in the shape of the almost parallel nanowires. Magnetic measurements showed that different electrodeposition potentials and electrolytic bath pH lead to different magnetic anisotropies on the nanowire array samples.

Influence of electrodeposition potential and heat treatment on structural properties of CdTe films

A modified Butler–Volmer model is developed to predict the potential of perfect stoichiometry (PPS) for electrodeposition. CdTe thin films are deposited in an acidic solution; their electrodeposition mechanism is investigated using cyclic voltammetry. Calculated and experimental PPS values exhibit good agreement. At PPS, well-connected granular CdTe thin films can be deposited; these are predicted to be intrinsic, and slightly p-type due to cadmium vacancies. Type conversion occurs only because of defect redistribution and local defect reactions after annealing; the converted n-type layer exhibits lower resistivity and higher mobility. A film annealed at 350 °C exhibits excellent crystallization.