Fe–Mn Alloys Electroforming Process Using Choline Chloride Based Deep Eutectic Solvents

Aqueous solvents, despite being effective in the electrodeposition of metals with positive reduction potential, fail to deposit metals with negative reduction potential due to their narrow electrochemical potential window. Deep eutectic solvents (DESs), a class of ionic liquids, are a promising alternative of inexpensive, biodegradable, non-toxic anhydrous solvents that present wide electrochemical potential windows. The present work reports on the potential of choline chloride/ethylene glycol DES in the electrodeposition of Fe–Mn alloys. Cyclic voltammetry tests showed that increasing the quantity of Mn in the bath composition decreases the deposition current of the alloy.

The Use of Mathematical Modelling Methods in the Creation of Composite Materials Based on Carbon Fibre Materials

The report provides data on the electrochemical modification of carbon-graphite fibers as the basis for the creation of composite materials. The results of studies of the electrodeposition of metals on pre-electrochemically modified carbon fiber materials (CFM) in order to obtain composite materials based on them are presented. The use of CFM for the creation of composite materials is associated with the possibility of deposition of metals, alloys or their compounds on the surface of their constituent fibers. Electrochemical treatment in aqueous solutions of electrolytes is a promising method for modifying the surface properties of carbon materials, including in order to improve their adhesive properties. Preliminary electrochemical modification of carbon fiber materials in indifferent solutions of electrolytes made it possible to obtain composite and nanocomposite materials with good adhesion of the electrodeposited metal to the surface of the fibers of carbon materials.When metals are deposited on carbon fiber materials, it is necessary to solve the problem of applying a uniform metal deposit or with a certain profile in the thickness of the material. In this case, it is effective to use methods of mathematical modeling of metal deposition processes in a flowing three-dimensional electrode. Depending on the selected modes of deposition of metal sediment on the CFM, some electrochemical parameters of the process and system may be dependent on both the time of the process and the thickness coordinate of the electrode. This is especially true for the value of the resistivity of the solid phase of the system, that is, carbon-graphite fibrous material. Other electrochemical parameters, such as the specific electrode surface, the exchange current and the transfer coefficient of the electrochemical reaction, the porosity of the material, etc., can also change during the electrodeposition of the metal on the CFM. It is proposed to take into account the change in the characteristic properties of modified carbon fiber materials in the mathematical modeling of the processes of electrodeposition of metals on carbon fiber materials in order to determine the technological parameters to improve the efficiency of the properties of composite materials. In order to implement mathematical models used in the calculation of electrochemical processes in the volume and on the surface of carbon fiber materials, a set of programs based on modern computational methods and programming languages has been developed.

ELECTRODEPOSITION OF METALS AND ALLOYS FROM AQUEOUS SOLUTIONS. REVIEW OF WORK OF EMPLOYEES FROM V.I. VERNADSKY NASU

The article examines in a historical perspective the issues that have been associated with the theory and practice of electrochemical deposition over the years of existence of the V.I. Vernadsky Institute of General and Inorganic Chemistry of NAS of Ukraine. Research in the field of electrochemistry of aqueous solutions, which was and is being carried out at the Institute, made a significant contribution to theoretical and applied electro­chemistry: the theory of electrode pro­cesses, electrochemistry of complex compounds, masstransfer, chemical power sources, electrocatalysis, electrochemical devices, theoretical and engineering electroplating, hydroelectro­metallurgy, electrochemical ecology and a number of other areas of modern chemistry. This article highlights issues related to research in the field of electrodeposition, namely: theo­retical research in the field of electrodeposition, electrodeposition of metals and alloys, hydroelectrometallurgy, corrosion and anticorrosion coatings. It is proved the effect of complexation leads to the formation of elect­rochemically active and inactive coordination ions, a mechanism for the discharge of ions during the formation of a film on the electrode surface is also proposed. The regularities leading to the formation of powders and black deposits of metals are analyzed. The conditions for a stable electrolysis regime were identified, the concept of the electrochemical resistance of the system was introduced, and the relationship between the kinetic parameters of elect­rolysis and the structure of the coatings was shown. The works in the field of hydroelectrometallurgy, corrosion-resistant and protective coatings are analyzed. It is noted that the scien­tific achievements of the Institute’s scientists are widely known around the world.

PARAMETERS AFFECTING QUALITATIVE AND EFFICIENT ELECTRODEPOSITION OF METALS IN AN ELECTROLYTIC CELL: A REVIEW

Electroplating has been a useful practice in the laboratory and industry for a long time. Its usefulness is more profound in oil industries for corrosion prevention and control, automobile industry, jewelries and decoration. Today, the scope of electroplating has expanded considerably with many players exploring its advantages and optimizing its parameters for enhanced productivity. The paper presented a review of electroplating with the aim of making concise information available on its process parameters and its process optimization. The review was compiled from several major work which pertained to parameters affecting qualitative and efficient electrodeposition of metals in an electrolytic cell. Results gathered included actual effect of identified parameters and interplay of parameter on quality of electrodeposition and microstructure of deposited metal. Important recommendations were made to further enhance the practice of electrodeposition.

NiOOH/FeOOH Supported on Reduced Graphene Oxide Composite Electrodes for Ethanol Electrooxidation

In this work, nickel (Ni) and Ni-Fe bimetallic microparticles were electrosynthesized at reduction potentials in the range from −0.70 V to −1.20 V (50 mV s−1) by cyclic voltammetry (CV) onto graphite/paraffin electrode surface modified with nanosheets of reduced graphene oxide (RGO). Previously, the RGO was electrodeposited by CV from a suspension of 1 mg mL−1 of graphene oxide in PBS solution with pH 9.18, in the potential range from −1.50 V to 0.50 V (10 mV s−1). After electrodeposition of metals, the oxyhydroxides were formed by CV in an alkaline medium of 0.10 mol L−1 of NaOH in the potential range from −0.20 V to 1.0 V (100 mV s−1) with successive scans until stabilization of currents. In order to characterize the developed electrodes composites, the surfaces were investigated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Electrochemical performance of the developed electrodes composites to ethanol electrooxidation was carried out in an alkaline medium of 0.10 mol L−1 of NaOH in the potential range from −0.20 V to 1.0 V (100 mV s−1) by CV. The electrodes were able to induce the electrooxidation of ethanol at a potential of 0.55 V for the electrode made of NiOOH/FeOOH and around of 0.60 V for the electrode modified with NiOOH.