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Surface Engineering and Applied Electrochemistry
Journal Prestige (SJR): 0.225  Citation Impact (citeScore): 1 Number of Followers: 7  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1068-3755 - ISSN (Online) 1934-8002 Published by Springer-Verlag  [2468 journals]
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- Size Effect in the Rate of Electrodeposition of Co–W Coatings from a
Citrate Bath-
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Abstract: — It is shown that two types of size effects in the deposition rate (i.e., a dependence of the electrodeposition rate on electrode surface area) can be observed for electrodeposition of Co–W coatings from a citrate bath: a microeffect associated with a relation between the size of microelectrodes and the diffusional current density and a macroscopic size effect related to the structure of an inducing species (a cobalt citrate complex).
PubDate: 2023-08-01
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- On the Interaction of Azimuthal Modes of Capillary Waves on the Surface of
an Elliptic Jet in a Homogeneous Electrostatic Field-
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Abstract: A study was made of the interaction of the first azimuthal modes of capillary waves on the surface of an elliptic jet in a homogeneous electrostatic field that is perpendicular to the axis of the jet. The interaction is nonlinear in the product of two independent small parameters. The interaction arises due to the ellipticity of the perpendicular cross-section of the jet and involves three azimuthal modes: either even or odd. The stability of the jet in the perpendicular homogeneous electrostatic field is lower than that of a jet in a radial electrostatic field. The characteristic destabilization time decreases with increasing initial amplitudes of the interacting modes and intensity of the external electrostatic field, and also depends on the wavenumber.
PubDate: 2023-08-01
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- Statistical Analysis of Surface Roughness of Ti–6Al–4V Products
Manufactured by Selective Electron Beam Melting-
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Abstract: A statistical study was made of the microgeometry parameters of the surface of vertical walls of an object of building by additive manufacturing using electron beam melting, and the effect of conditions of building and parameters of hatching mode on surface roughness was estimated. It was determined that the parameters of hatching mode affect the roughness of the lateral surface when building samples with vertical walls. It was shown that the average height of surface roughness, Rz, increases as the energy of hatching mode is intensified. A physical model was proposed to describe the effect of parameters of hatching mode on the roughness of vertical walls, which is based on the hypothesis that a melt microflow can penetrate during hatching onto the external surface of the contour. It was demonstrated that the distribution of surface roughness values of vertical walls is non-Gaussian, and the curves are typically right-skewed (the mode is located to the left of the center of size grouping), which indicates the influence of non-random factors whose number or values systematically change over time.
PubDate: 2023-08-01
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- Features of Deformation of Droplets of Magnetic Emulsions in an
Alternating Electric Field-
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Abstract: — Features of deformation of microdroplets of magnetic emulsions in an alternating electric field were experimentally investigated. It was shown that the deformation behavior can vary depending on the frequency of the electric field: at low frequencies, the droplets flatten along the field direction, and at higher frequencies, they elongate. It was found that the frequency value corresponding to the transition from the flattened to the elongated droplet shape depends on the electrical conductivity of the droplet, the intensity of the electric field, and temperature. It was demonstrated that the droplet deformation caused by the electric field can be compensated for by the additional application of a magnetic field. Analysis of the obtained results took into account the movement of liquid phases due to the accumulation of free charge at the interfaces of the droplets and the electrodes creating the field.
PubDate: 2023-08-01
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- Corrosion Inhibition of Mild Steel in Hydrochloric Acid Medium Using
Schiff Base Synthesized by Green Approach-
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Abstract: The (1E)-benzylidene hydrazine was tested as a corrosion inhibitor for mild steel in 0.5 M HCl by using polarization and electrochemical impedance spectroscopy measurements at temperatures 303, 313, 323, and 333 K. The data obtained from those two methods were in good agreement with each other. The effect of an increase in temperature and a change in the concentration of the inhibitor were studied. The inhibition efficiency was found to increase with an increase in the inhibitor concentration. The maximum inhibition efficiency of 92% was observed for 500 ppm of the inhibitor at 323 K. Polarization measurements showed that the Schiff base acts as a mixed type of inhibitor involving both physisorption and chemisorption. Temperature studies revealed that the inhibition efficiency increased at temperatures up to 323 K, but, beyond that, the inhibitor efficiency decreased due to the desorption of the inhibitor. The adsorption of (1E)-benzylidene hydrazine on a mild steel surface is an endothermic process and was best described by the Langmuir adsorption isotherm. Both kinetic and thermodynamics adsorption parameters were calculated and discussed. The surface morphology of the uninhibited and inhibited mild steel samples was analyzed using scanning electron microscopy, and energy dispersive X-ray spectroscopy. The results obtained from the quantum chemical analysis are well correlated with other experimental ones.
PubDate: 2023-08-01
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- Study into the Influence of Technological Conditions of Electric Discharge
Installation Operation on the Prebreakdown Characteristics of Electric
Discharge-
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Abstract: This work deals with the influence of the parameters of the working fluid (hydrostatic pressure, temperature, specific electrical conductivity) and the geometry of the electrode system (the length of the interelectrode gap and the uninsulated part of the anode) on the prebreakdown characteristics of an electric discharge in a liquid aqueous electrolyte (breakdown voltage and breakdown delay time) and the minimum charging voltage, which provides a stable high-voltage breakdown of the interelectrode gap. The research has shown that an increase in the hydrostatic pressure leads to an increase in most of the characteristics under study. At the same time, an increase in the specific electrical conductivity and temperature was observed to lead to their decrease. It was suggested that the effect of temperature on the prebreakdown characteristics is associated with a change in the specific electrical conductivity of the working fluid during its heating. The data obtained showed no effect of the length of the interelectrode gap on the breakdown voltage and its breakdown delay time as well as the minimum charging voltage. The results of the experimental studies made it possible to develop a criterion for determining the charging voltage that provides a stable high-voltage breakdown of the water interelectrode gap. Its experimental verification has shown that it can be applied to the design of electric discharge equipment and to the choice of technological modes of operation in the specified range of parameters.
PubDate: 2023-08-01
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- Hole Formation in Semiconductor Materials by Laser Microprocessing
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Abstract: — The process of laser formation of microholes in semiconductor substrates using an EM-4452-1 laser-processing unit with a pulse repetition frequency of a picosecond laser from 10 to 300 kHz at a radiation energy up to 10 μJ is investigated. The combination of high-speed movements of the laser beam by the galvanoscanner system and precise positioning of the processed material increases the efficiency of laser microprocessing and expands the functional capabilities of the equipment.
PubDate: 2023-08-01
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- Consideration of the Synergy of Vitamins E and C in the Kinetic Model of
Lipid Peroxidation-
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Abstract: — A theoretical model of the kinetics of lipid peroxidation is considered in which the synergy effect of vitamins E and C is taken into account. Approximations simplifying the model system with consideration of the features of the process of lipid peroxidation are analyzed. The obtained model is minimal and sufficiently adequately describes lipid peroxidation at the stages that are significant for effective control of this process as a whole.
PubDate: 2023-08-01
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- Experimental Investigation of Nano Al2O3 Filled Silicone Rubber Specimen
Used in Outdoor Insulation-
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Abstract: Composite insulators are popular choice in contemporary power industry due to their numerous advantages. When these insulators are subject to various stresses, their performance gets affected due to the material degradation. One of the methods to improve the material property is to incorporate inorganic nanofillers. In this work, aluminum oxide nanofillers, synthesized in the laboratory using a solution combustion process were used and studied. The nano range was ascertained with X-ray diffraction. Those fillers were mixed in the silicone rubber specimens in 0, 1, 3, and 5 wt % concentrations. They were more rapidly aged under UV radiation, temperature, humidity and electric stresses. Dry and wet flashover tests were carried out on both virgin and aged samples, and the results showed that the concentration of 3 wt % offered a better breakdown voltage. Fourier transform infrared spectroscopy revealed percentage variations in the properties of the aged specimens, the aging resistance, degradation resistance, hydrophobicity, oxidation resistance, and erosion resistance were significantly better in 3 wt % Al2O3 filled samples. Scanning electron microscopy with energy dispersive X-ray spectroscopy images showed that at 3 wt % concentration there was a fairly uniform distribution of nanofillers in the silicone base and there was the least ingress of water at same weight percentage of specimens. Their improvements in the insulation property is primarily attributed to the fair distribution of nano Al2O3 fillers into the silicone base, a good Si–CH3 bond structure, a low carbon cross linking and good percolation, which makes them the best candidates for outdoor insulation of power systems.
PubDate: 2023-08-01
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- Combustion Synthesis of SrAl2O4:Eu2+ Phosphor. Photoluminescence and
Cathodoluminescence at Low Temperatures-
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Abstract: Eu2+ doped strontium aluminate (SrAl2O4:Eu2+) nanosized phosphorescent powders were prepared by the urea-nitrate solution combustion method at 500°C for 5 min. The average particle size of the powders was about 80 nm. The photoluminescent properties were studied using ultraviolet excitation as well as high energy synchrotron radiation, and electron beam excitation. Broad photoluminescence bands were observed in SrAl2O4:Eu2+ peaking at λmax = 450 and 520 nm which arise due to transitions from the 4f 65d1 to 4f 7 configuration of the Eu2+ ions situated in two sites with a different symmetry. One additional emission band was also observed at 360 nm. The nature of that band is under discussion.
PubDate: 2023-08-01
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- Intensification of the Processes of Extraction of Humic Acids from
Biosubstrates under the Action of Electric Discharges-
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Abstract: The article deals with the study of factors participating in the extraction of humic acids from plant substrates under the action of electric discharges. Using the example of the electric discharge treatment of the peat-water suspension, it was demonstrated that the main factor affecting the intensity of extraction is the degree of the biosubstrate-water suspension solid phase grinding, which depends on the pressure amplitude at a distance equal to the inner radius of the chamber and the number of discharge pulses. The experimental research has shown that the amount of chemical reagents (alkalis) commonly used in the extraction of humic acids from peat can be significantly reduced due to the appearance of radicals and peroxide compounds in the peat-water suspension during the action of an electric discharge. The perspectives of the nonthermal electric discharge method to intensify the extraction of humic acids from biosubstrates are determined.
PubDate: 2023-08-01
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- Colloidal Silver Activation for Electroless Copper Deposition
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Abstract: Palladium is commonly used as a catalyst in the process of surface metallization of acrylonitrile-butadiene-styrene (ABS), but since palladium is expensive, alternatives are sought. In this study, colloidal silver was used as the catalyst to metallize an ABS surface, and the effect of colloidal silver on the electroless copper plating of the ABS surface under different conditions was studied. The average bonding strength was 1.37 kN/m, which is much higher than that of palladium colloid. The experimental results show that colloidal silver has good catalytic activity, and it is expected to be used in metallization of industrial non-conductive surfaces.
PubDate: 2023-08-01
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- Experimental Investigation of the Effect of Deep Cryogenic Treatment of
100Cr6 Bearing Steel-
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Abstract: Cryogenic treatment is the process of cooling a material to extremely low temperatures to generate enhanced mechanical and physical properties. The present investigation examines the effect of a deep cryogenic treatment on the enhancement of mechanical properties, such as the wear resistance, the corrosion resistance, the tensile strength, and the impact strength of the plunger material 100Cr6 bearing steel. An improvement in those properties of the deep cryogenically treated samples over the conventionally heat treated ones was found to be 50, 26, 13, and 27%, respectively. This study suggests that the formation of very small carbides dispersed in the tempered martensite structure can be the main reason for the enhancement of certain mechanical properties, along with the retained austenite transformations.
PubDate: 2023-08-01
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- Effect of a Constant Magnetic Field on Electrodeposition of CoMo, CoRe,
and CoMoRe Alloys from a Citrate Electrolyte-
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Abstract: — Electrodeposition of CoMo and CoRe binary alloys and CoMoRe ternary alloys from a citrate electrolyte (pH 3.5) was studied depending on the presence of a magnetostatic field and the direction of the magnetic induction vector relative to the surface of the working electrode. It was shown that magnetoelectrolysis significantly increases the current efficiency of all investigated alloys, especially the CoMoRe ternary alloy. The forces acting in the liquid and on bubbles of hydrogen evolved during a reaction in a magnetostatic field were modeled. It was demonstrated that the generation of convective flows by magnetohydrodynamic effect is neither single, nor determining factor. In the case of intense gas evolution, the force balance varies depending on the size of the bubbles: the conduction force and the buoyancy force dominate for large bubbles (about 100 μm), whereas the magnetic gradient force is predominant for small bubbles (less than 1 μm).
PubDate: 2023-08-01
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- A Theoretical Study of Structure and Corrosion Inhibition of Some
Heterocyclic Imidazoles: DFT Investigation-
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Abstract: The polarizable continuum model was used for four different compounds to investigate the impact of substituent groups, of the number of π-electrons, of the electron-accepting and electron-donating properties on the corrosion inhibiting properties in both aqueous and gas phases for the neutral and cationic forms of the studied subsdtances. Measures for the corrosion prevention of metals are of great importance in the industrial, environmental (or ecologic), aesthetic, and economic fields. The use of inhibitors is the best way to preserve metals and alloys from corrosion. The purpose of this study was to apply quantum chemical calculations in the research of the corrosion inhibition and adsorption properties of four compounds with various heteroatoms or substituent groups but with similar chemical skeleton structures: 2-mercaptoimidazole, 2-mercapto-5-methyl benzimidazole, 2-mercaptobenzoimidazole, and 2-mercapto-5-nitrobenzimidazole, shown in Figs. 1 and 2 and designated as A, C, B, and D, respectively. The quantum chemical computations sector of the study gives complete calculation details and discussion on the correlation between corrosion inhibition and global reactivity descriptors such as the energy of the highest occupied molecule orbital, the energy of the lowest unoccupied molecule orbital, total energy, ionization energy, electron affinity, electronegativity, energy gap, hardness, softness, dipole moment, electron transfer, chemical potential, electrophilicity, nucleophilicity, and back-donation energy. The calculations were carried out using the general purpose computational chemistry software package Gaussian 09. The total calculations have been done based on the density functional theory at 6-311++G(d, p) basis set and applying the hybrid functional B3LYP level taking into account the exchange and the correlation with three parameters defining the hybrid Becke’s functional (Becke—the exchange part, and Lee, Yang and Parr—the correlation part). Based on the calculations performed in this paper, the following summary ranking was obtained for the corrosion inhibition efficiency: A > B > C ≈ D for neutral forms and A > B > C > D for cationic forms in the gas phase, A > C ≈ D > B for neutral forms and A ≈ B > C > D for cationic forms in the aqueous phase. Thus, inhibitor A should be considered to be the best one in all cases.
PubDate: 2023-08-01
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- Heat Transfer during Boiling of a Magnetic Fluid in a Magnetic Field on a
Horizontal Surface with Single-Point Heat Supply-
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Abstract: — An experimental study was made of the influence of a homogeneous magnetic field on heat transfer during nucleate boiling of a nanodispersed magnetizable fluid (magnetic fluid) on a horizontal surface with single-point heat supply. The boiling curves were obtained for magnetic fluids with volume concentrations of the solid phase of 12, 8, and 5.5% in magnetic fields ranging from 0.7 to 4.2 kA/m. The curves are nonmonotonic, and the value of the magnetic field intensity at which the heat flux is maximum was determined. It was found that, with an increase in the solid-phase concentration, the effect of the magnetic field on the heat flux increases. Based on the theory of approximate heat transfer during boiling of fluids, an expression was derived that satisfactorily describes the influence of the magnetic field on the heat flux in the nucleate boiling regime.
PubDate: 2023-08-01
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- Plasma-Electrolytic Coatings Obtained on VT1-0 Titanium with a Short
Processing Time-
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Abstract: The possibility of obtaining thin continuous plasma-electrolyte protective oxide coatings on VT1-0 titanium in a nickel sulfate alkaline electrolyte without the addition of silicates in the sparking mode was studied. The elemental composition and the microstructure of coatings manufactured via plasma electrolytic oxidation (PEO) both on the substrate and after the destruction of the coating in 25% sulfuric acid were studied. As a result of the research, a possibility of forming thin (1–7 μm) continuous PEO coatings, with a treatment duration of 3–10 min, respectively, was established. The introduction of additives (for example, nickel sulfate) into the electrolyte is effective when the duration of PEO is more than 10 min. It was supposed that nickel was incorporated into the coating mainly due to the action of plasma microarcs. The limited corrosion resistance of the resulting coatings in aggressive media was noted. An analysis of the elemental composition of the dry residues of the coating after destruction in a 25% sulfuric acid solution gives grounds to assume the electrochemical nature of the corrosion destruction of such coatings.
PubDate: 2023-08-01
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- Study of Magnetoelectric Properties of Composites Based on Magnetic
Particles of Fe2O3 and Bentonite Using Percolation Theory-
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Abstract: The paper presents the results from studies of the electrical and magnetic properties of an inhomogeneous percolated medium based on the theory of percolation. The application of this theory has a wide and varied range. Examples include hopping conductivity in semiconductors, properties of porous materials, etc. It was found that, with approaching the percolation threshold pc = 0.35, the resistivity decreases, and the electrical conductivity increases accordingly. An increasing number of individual ferromagnetic nanogranules in (p)–Fe2O3–(1–p) (MBT) composites merge with the formation of individual Fe2O3 clusters in the bentonite matrix, which combine to form a continuous network of clusters. This is due to the fact that the resistivity ρ of the composite is mainly determined by the magnetic component of the latter.
PubDate: 2023-06-01
DOI: 10.3103/S1068375523030092
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- An Ionic Boundary Layer near the Lithium Niobate Surface in the Proton
Exchange Process-
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Abstract: The paper presents a theoretical study of the behavior of an ionic boundary layer that occurs in the process of a steady proton exchange in a benzoic acid melt contacting with the surface of a lithium niobate crystal. The penetration of protons into a crystal promotes the injection of oppositely charged ions (lithium and benzoate) from the surface of lithium niobate in the surrounding acid. The transfer of the reaction products and their interaction in benzoic acid is studied numerically. The proposed mathematical model includes the effect of recombination in the volume so that the ions with different charge signs approach each other and form a neutral lithium benzoate. The results of the numerical simulations demonstrate that there are exponential-like concentration profiles of two types of ions, and a non-uniform electric field and pressure distributions develop in the boundary layer under steady-state conditions. In this process, the total charge of the system remains zero. It is shown how the concentration, recombination, and activity of lithium and benzoate ions and the diffusion coefficients affect the profile shapes and the process intensity.
PubDate: 2023-06-01
DOI: 10.3103/S1068375523030055
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- Characteristics of Сhanges in the Electrical Conductivity Properties of
Weed Plant Tissues under Electropulse Damage-
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Abstract: — This work is devoted to one of the promising electrical technologies in agriculture: the electro-pulsed weeding of undesirable and weedy plants. This operation has high technological efficiency, is environmentally safe, and belongs to high-tech processes. Various electrical properties and parameters of the objects of influence, weeds, have been studied for practical application and technical implementation. The frequency dependence of the electrical resistance of plant tissue or the dispersion of this resistance over the frequency of the measuring current is used as the main studied characteristic. Experimental studies have allowed the authors to determine the nature of changes in resistance during plant tissue damage, which additionally makes it possible to evaluate such quantitative indicators as the energy absorbed by plant tissue and the ranges of variation of its resistance during the electro-impulse impact on it. Theoretical verification confirmed the qualitative convergence of the obtained results and their changes during damage with calculated values.
PubDate: 2023-06-01
DOI: 10.3103/S1068375523030171
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