Том 53, № 6 (2017)

In this work, we report the effect of triazole stabilizers: aminotriazole (ATA), benzotriazole (BTA), and tolytriazole (TTA) on the electroless deposition of copper thin film using xylitol containing copper methanesulphonate bath. Eco-friendly glyoxylic acid was used as reducing agent instead of p-formaldehyde which is carcinogenic. Potassium hydroxide was used for adjusting the pH, since it has the advantage of preventing the formation of insoluble byproducts in electroless bath, which is possible when NaOH is used. The electroless bath was optimized by addition of 1 ppm concentration of stabilizers, at 45°C and pH of 13.25 ± 0.25. Surface roughness, crystallite size and specific surface area of copper deposits were studied by the atomic force microscopy and X-ray diffraction. The anodic peak potential and corrosion current values were analyzed by the cyclic voltammetry and the Tafel plot. ATA was found to inhibit copper deposition while both BTA and TTA accelerated it. The crystallite size and surface roughness values were found to be less than 100 nanometer (nm) compare to the xylitol plain bath. TTA resulted in a better surface, structural, physical and electrochemical property of copper deposition than ATA and BTA.

The effect of the electrolyte composition and the stationary electrolysis parameters on the composition and morphology of Fe–Mo and Fe–Co–Mo coatings deposited from complex citrate electrolytes based on Fe(III) is studied. It is shown that, at a constant component ratio of с(Fe³⁺): с(Co²⁺): с(MoO²⁻₄): с(Cit^3–) = 2: 2: 1: 4, an increase in the electrolyte concentration leads to a decrease in the pH of the solution in a range of 4.85–4.30 and in the molybdenum content in the coating. An increase in the current density contributes to the molybdenum enrichment of the electrodeposited alloy in the entire range of electrolyte concentrations. The Fe–Mo alloy coatings have a rough microporous surface; an increase in the current density does not lead to significant changes in the surface topography. It is found that the formation of ternary coatings is characterized by the competitive reduction of iron and cobalt in the alloy; the molybdenum content depends on the current density. At a metal ratio of 3: 2: 1 and a molybdenum content of up to 17 at % in the Fe–Co–Mo alloy, the surface has a fine-grained needlelike structure typical of cobalt. With an increase in i_c, the atomic fraction of molybdenum increases, while the surface becomes microglobular. The Fe–Co–Mo electrodeposits with a metal ratio of 2.5: 1.5: 1.0 and a molybdenum content of 19–20 at % have a more developed surface with a high density of spheroids.

The purpose of the paper was searching for new “green” energy sources. The changes in the mechanism and the selectivity of components binding from the enzyme mixture extracted from black radish adsorbed on kaolin and aerosil are demonstrated. The differences in the binding mechanisms of metal-containing sites of enzyme molecules based on the implementation of the spatial separation of enzyme fragments containing Fe, Ni, Cu and Zn-ions are mentioned. The implementation of the charge division forms of heterostructures improves the oxidation activity and stability of the immobilized enzyme mixture and creates conditions for the formation of regions capable for specific adsorption of a charge. The spatially separated binding of enzyme fragments to an inorganic carrier exhibits the stabilizing effect on the formation of the areas capable for charging and accumulating red-ox transformations. Electrochemical methods have shown a possibility for the formation of structures responsible for the accumulation of energy, like a supercapacitor, in the immobilized systems consisting of graphene covered by a natural enzyme bound to an inorganic carrier.

The inhibitive action of root and shoot extracts of Ajuga chamaecistus subsp. scoparia as a green inhibitors on corrosion of 304 stainless steel in the 6.0 M HCl solution was studied by the weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy, and atomic force microscopy. The results demonstrate that the extracts act as a show mixed-type inhibitor. The Nyquist plots display an increase of the charge transfer resistance with an increase of the inhibitor concentration and a decrease of the double layer capacitance. The effect of temperature and related activation parameters was deliberate. Adsorption of the extract followed the Langmuir isotherm model. The inhibition efficiencies found from electrochemical tests were in good agreement with those observed via the weight loss method. The inhibition efficiencies for root and shoot extracts are 99.4 and 99.6%, respectively.

This work investigate the wear behavior of Fe–B–Cr coatings on medium carbon steel (EN24) substrate is used for several automotive parts. The high velocity oxy-fuel (HVOF) method was used to create the new crystalline coating of Fe–B–Cr (composition of 59%Fe–26%B–15%Cr in wt %) on a medium carbon steel substrate (AISI 4340). The characteristics of powder and coating are investigated using scanning electron microscopy (SEM) merged with energy dispersive spectroscopy (EDS), optical microscopy (OM) and thermogravmentric analysis (TGA) which were undertaken in the partial characterization of the coating. The phase contents of both powder and coatings were studied by X-ray diffraction (XRD). The coatings consist of melted and un-melted particles identified in the coatings. Moreover, oxides and micro-cracks were observed at the surface. The mechanical property of the coatings was characterized using a microhardness test. The hardness value increased three times more than the substrate. The coated surface showed lower levels of porosity. Moreover, the electrochemical investigation found Fe–B–Cr coating on medium carbon steel. The corrosion test was carried out in an environment with 0.5 M of NaCl, which showed that the corrosion resistance improved by coating.

This paper proposes a new process to separate components at the recovery of waste printed circuit boards and probably other waste of electronic equipment production.