Vanadium Particles Research Articles

Classification of pairing phase transition in metal clusters in vanadium and aluminum particles using Grossman theory

In this work, the phase transition from normal to superconductivity state of two metal clusters, vanadium and aluminum particles, are theoretically studied by changing size and resistance parameter. We obtained the heat capacity integral of Grossman's theory considering that the first zero of the partition functions is located in the complex temperature plane. Then, we used the experimental data of the heat capacity of aluminum metal clusters and vanadium particles to determine the unknown integral coefficients of the heat capacity of Grossman's theory. Based on the obtained coefficients, we discussed the classification of the phase transition of the aforementioned metal clusters. Also, the obtained coefficients have been used to plot the heat capacity of aluminum metal clusters and vanadium particles. Finally, we compared the obtained heat capacity with the experimental results. A good agreement between our results and the experimental data has been obtained.

Hot deformation behavior and processing map of vanadium particles reinforced AZ31 composite

The vanadium particles reinforced AZ31 matrix composite (VP/AZ31) was prepared using the powder metallurgy method. Subsequently, hot deformation behavior of VP/AZ31 composite was studied through hot compression trials. The experimental parameters were set in a temperature range of 250–400 °C and a strain rate range of 0.001–1 s−1. Based on the experimental results, a strain-compensated Arrhenius constitutive model was developed to accurately forecast the flow behavior of VP/AZ31 composite. Moreover, the thermal activation energy was calculated to be 138.605 kJ/mol and the processing map was delineated according to the dynamic material model theory. The processing map revealed that the optimal processing area existed under 363–400 °C/0.001–0.004 s−1, where the efficiency of power dissipation exceeded 23 %. Notably, the highest efficiency of power dissipation occurred at 400 °C/1 s−1, which exceeded 30 %. Under these conditions, dynamic recrystallization (DRX) was sufficiently developed, indicating the enhancement of workability. It is estimated that the instability region for VP/AZ31 composites occurred within the conditions of 250–325 °C/0.16–1 s−1, characterized by crack formation. The DRX of VP/AZ31 composite is predominantly governed through the mechanism of discontinuous DRX (DDRX).

V–Cd nanoparticle-formed alloys: fabrication, phase composition and structure

The results of the study of targeted sputtering and deposition of ultrafine vanadium and cadmium particles on substrates that are not heated and shifted with respect to the substrate plasma currents are revealed. As a result of the conducted studies, coatings were obtained in the range with a concentration of cadmium from 9.6 to 88.6 at.%. The critical size of vanadium particles capable of forming alloys with cadmium is 0.6 nm. The concentration limit for the presence of solid solutions of cadmium in vanadium is the cadmium content of ~37 at.%, at a higher cadmium content the film coating is represented by a mixture of cadmium phases and a solid solution of cadmium in vanadium. The dependence of the lattice parameter of α-vanadium on the content of cadmium in it corresponds to the expression: а [nm] = 8·10–4СCd + 0.3707, where СCd is the concentration of cadmium, at.%. On the surface of the sample in the region of solid solutions (31.6 at.% Cd), the presence of threadlike crystals of cadmium was found, the reason for the appearance of which is the lattice pressure of the matrix metal. Annealing of films rich in cadmium (69.5 at.%) in vacuum is accompanied by cracking of the coating and the formation of pores. The latter can be used as a method for obtaining porous vanadium.

Microstructure and thermal stability of nanocrystalline AZ31 Mg alloys reinforced by ultrafine vanadium particles

In this paper, the microstructure evolution and thermal stability of nanocrystalline (NC) AZ31-2.5 wt%VP magnesium matrix composites were studied, while the hardness was analyzed. The results showed that the NC AZ31-2.5 wt%VP still kept NC scale after annealing at 300 °C and 350 °C. Even at 400 °C and 450 °C, the grain size of the annealed composite only grew to 113 nm and 132 nm, which was still in ultrafine grain scale, illustrating excellent thermal stability of NC AZ31-2.5 wt%VP. Furthermore, the V particles, which was uniformly distributed in the Mg matrix, had no obvious change in dimension after annealing, while it also had no new phase formed. The stabilization mechanism was expounded and found that the pinning effect of V particles effectively inhibited the grain growth of Mg matrix at high temperature. In addition, the grain growth kinetics equation (D6−D06=kt) was utilized to explain the grain growth behavior of NC AZ31-2.5 wt%VP, and the activation energy (Ea) of grain growth was calculated to be 130.9 kJ/mol, which was much higher than that of pure Mg (92 kJ/mol). Eventually, the hardness of NC AZ31-2.5 wt%VP was contrastive studied and the hardness evolution curves at different temperatures were obtained. After annealing treatment was performed at 450 °C for 180min, the hardness remained at 80 HV, which was higher than that of as-cast AZ31 (53 HV).

Contribution of vanadium particles to thermal movement of correlated two-dimensional pancake Abrikosov vortices in Bi-2223 superconducting system

This article breaks new ground in understanding of variation in the magnetic strength performance, flux pinning and energy dissipation mechanism of polycrystalline bulk Bi1.8Sr2.0Ca2.2Cu3.0Oy (Bi-2223) superconducting materials added with the different vanadium concentration level (0.0≤x≤0.30) under the magnetic field strengths applied up to 5T for the first time. We provide the sophisticated and phenomenological discussions on the magnetoresistivity measurement results in three main sections along the paper. All the findings show that the increase of both the vanadium concentration in the crystal structure and external magnetic field strength damages significantly the magnetic strength performance, vortex dynamics, flux pinning ability and vortex lattice elasticity of bulk Bi-2223 superconducting ceramics. The vanadium addition promotes thermally the movement of correlated two-dimensional (2D) pancake Abrikosov vortices between the in-plane Cu–O2 layers in the valance band, vortex lattice elasticity, vortex dynamics, distance for interlayer Josephson couplings and flux pinning centers and the theoretical computations confirm the remarkable degradation in the formation of super-electrons in the Bi-2223 crystal system. Thus, the vanadium addition is anticipated to be one of the best selectable materials to examine the differentiation in the thermal movement of correlated 2D Pancake Abrikosov vortices in the bulk Bi-2223 superconducting system.

Angular distribution of particles sputtered from the vanadium target by 5 keV Kr ions: simulation study

The sputtering of vanadium particles at normal incidence was simulated. The SRIM-code combined to a new ANGULAIR and SDTrimSP simulation was employed to obtain the sputtering yields and the angular distribution of the atoms. The simulation was made for a large number of incident Kr+ ions with 5 keV energy, letting the computer count the number of emitted particles in the solid angle. The angular distribution of differential sputtering yields of vanadium shows an over-cosine tendency.

Microstructure and mechanical properties of AZ31 magnesium alloy reinforced with novel sub-micron vanadium particles by powder metallurgy

In this study, a novel fine-grained AZ31 magnesium (Mg) alloy reinforced with sub-micron vanadium particles (VP) was prepared by powder metallurgy (P/M). It was found that VP could accelerate the pile-up of dislocations and the refinement of Mg crystallite sizes during the milling process. The Mg matrix was refined to nanocrystalline scale after milling for 90 h, and the ultimate average crystallite size was only 25 nm. Meanwhile, a homogeneous distribution of the sub-micron VP in Mg matrix was achieved. After hot-extrusion process, the average grain size of Mg matrix was 3.08 μm, which reached fine-grained scale. Additionally, the AZ31-2.5 wt % VP composite exhibited competitive mechanical properties. Compared to the as-cast AZ31 Mg alloy, the microhardness, yield strength, ultimate tensile strength and elongation of AZ31-2.5 wt % VP composite increased by 102%, 128%, 59% and 10%, respectively. The grain boundary strengthening played a dominant role in improvement of strength. Simultaneously, the strengthening mechanisms of thermal mismatch, Orowan strengthening and load transfer also made a contribution. Besides that, the fracture mechanism of the AZ31-2.5 wt % VP composite included ductile and brittle fracture mode.

Effect of Vanadium Reinforcement on the Microstructure and Mechanical Properties of Magnesium Matrix Composites

In this work, vanadium particles (VP) were utilized as a novel reinforcement of AZ31 magnesium (Mg) alloy. The nanocrystalline (NC) AZ31–VP composites were prepared via mechanical milling (MM) and vacuum hot-press sintering. During the milling process, the presence of VP contributed to the cold welding and fracture mechanism, resulting in the acceleration of the milling process. Additionally, increasing the VP content accelerated the grain refinement of the matrix during the milling process. After milling for 90 h, the average grain size of AZ31-X wt % Vp (X = 5, 7.5, 10) was refined to only about 23 nm, 19 nm and 16 nm, respectively. In the meantime, VP was refined to sub-micron scale and distributed uniformly in the matrix, exhibiting excellent interfacial bonding with the matrix. After the sintering process, the average grain size of AZ31-X wt % VP (X = 5, 7.5, 10) composites still remained at the NC scale, which was mainly caused by the pinning effect of VP. Besides that, the porosity of the sintered composites was no more than 7.8%, indicating a good densification effect. As a result, there was little difference between the theoretical and real density. Compared to as-cast AZ31 Mg alloy, the microhardness of sintered AZ31-X wt % VP (X = 5, 7.5, 10) composites increased by 65%, 87% and 96%, respectively, owing to the strengthening mechanisms of grain refinement strengthening, Orowan strengthening and load-bearing effects.

Effects of high temperature wear and corrosion behaviour of sintered titanium reinforced with vanadium particle

Effects of high temperature wear and corrosion behaviour of sintered titanium reinforced with vanadium particle

Effects of high temperature wear and corrosion behaviour of sintered titanium reinforced with vanadium particle

The present investigation deals the high temperature wear and corrosion behavior of sintered Titanium (Ti) reinforced with vanadium (V) particles with various wt. % such as 3, 6 and 9. The surface morphology followed to that elemental confirmation of the sintered composites were identified using Scanning Electron Microscope (SEM) embedded with Electron Dispersive Spectroscopy (EDS). The high temperature wear behavior of the sintered composites was evaluated using pin on disc apparatus with varying the operating temperature (50°, 100° and 150°C). By using TAFEL exploration the corrosion behavior of the composites were assessed. The results revealed that Ti reinforced with 6 % of V possessed better wear resistant and corrosion resistance properties. Furthermore, the surface morphological changes of wear and corrosion behavior after experimentation were viewed using SEM.

Evaluation of crystallographic and electrical-superconducting features of Bi-2223 advanced ceramics with vanadium addition

In the current study, the effect of vanadium particles on the electrical, superconducting, crystallographic, key structural and morphological features of Bi1.8Sr2.0Ca2.2Cu3.0VxOy superconducting materials is examined with the aid of powder X-ray diffraction (XRD), scanning electron microscope (SEM), electron-dispersive X-ray (EDX) and dc electrical resistivity over the temperature (ρ-T). The vanadium-added Bi1.8Sr2.0Ca2.2Cu3.0VxOy (Bi-2223) superconducting materials are prepared within the molar ratios between x = 0.00 and 0.30 using the conventional solid-state reaction technique. The temperature-dependent electrical resistivity measurements show that the existence of vanadium atom in the superconducting system damages seriously the Bi-2223 (high-Tc) phase content in the crystal structure as a result of the formations/disappearances of new impurity phases. On this basis, the amplitude Ψ0 of wave function founded on the super-electrons is considerably reduced with the vanadium addition. The critical onset and offset transition temperature values truncate from the values of 110.92 K and 97.45 K to 103.17 K and 18.38 K in case of the maximum vanadium addition level of x = 0.30. Similarly, the XRD results present that the average crystallite size and c-axis length parameters are noted to decrease considerably whereas a-axis length, strain and relativistic dislocation density ratios are calculated to enlarge harshly depending on the addition content level. It is also obtained that the vanadium inclusions lead to increase seriously the permanent crystal structure problems, disorders, misorientations, lattice strains, crack-producing omnipresent flaws and grain boundary coupling problems in the active Cu–O2 consecutively stacked layers in the superconducting core, being assured by SEM analyses. Besides, the SEM results show that the enhancement of vanadium addition level in the crystal structure damages remarkably the flaky layers of platelet-like shape for the grains. In fact, the excess vanadium addition seriously damages the general characteristic view (flaky layer structure) of Bi-2223 compound. Based on the EDX findings, the main reason for the degradation of fundamental characteristic properties of Bi-2223 system may stem from the possible replacement of aliovalent vanadium impurities for the copper-sites in the crystal structure. Namely, the vanadium addition in the crystal structure is ploughed to improve the fundamental crystallographic and electrical-superconducting features of bulk Bi-2223 superconducting materials.

EXAMINATION OF VANADIUM EFFECT ON GENERAL MECHANICAL CHARACTERISTICS OF Bi-2223 MATERIALS VIA SEMI-EMPIRIC MODELS

In the current work, we semi-empirically investigate the load-independent Vickers hardness values of vanadium added Bi-2223 compounds in the plateau limit regions evaluated from the experimental microhardness graphics (Vickers hardness parameters versus applied indentation test loads) to determine the role of vanadium particles on the general mechanical characteristics with the aid of six mechanical modeling approaches, namely law of Meyer, proportional sample resistance, elastic/plastic deformation, modified proportional sample resistance, Hays-Kendall and indentation-induced cracking models. Throughout the study, the samples are prepared with the different molar rations varying from x=0 to 0.3 by the conventional ceramic method in the normal atmospheric pressure at the room temperature conditions. All the model findings show that the mechanical performances tend to constantly reduce with increasing the vanadium concentration level embedded in the Bi-2223 superconducting crystal system. This is in accordance to the fact that the concentration level of vanadium remarkably damages the main structural problems and permanent irreversible deformations. In this respect, it is not wrong to verify that the vanadium inclusions unstabilize the inherit durable tetragonal phase of Bi-2223 inorganic solids, resulting in the regression in the mechanical durability (resistance towards to the applied loads) in case of the applied test loads. Moreover, the models indicate that every material prepared exhibits the conventional indentation size effect (related to the formation of elastic and plastic deformations in the host crystal structures simultaneously due to the recovery of systems) but within the suppression trend. Shortly, all the semi-empiric models preferred in the present work are found to be useful descriptors to define the suitable relationship between the ion-addition mechanism in the crystal lattice and mechanical durability/performances of vanadium-added Bi-2223 materials. We should, of course, declare here that Hays–Kendall approach is gathered to be the best approach model for the load-independent Vickers hardness values in the plateau limit regions.

Effect of vanadium addition on fundamental electrical quantities of Bi-2223 crystal structure and semi-empirical model on structural disorders-defects

The primary contribution of the present study is to determine the effect of vanadium addition on the fundamental aspects of characteristic crystalline and electrical quantities for the Bi1.8Sr2.0Ca2.2Cu3.0VxOy (0.00 ≤ x ≤ 0.30) crystal system using the powder X-ray diffraction (XRD), temperature-dependent electrical resistivities and semi-empirical approaches founded on the structural disorders-defects. The dc electrical resistivity results show that every electrical quantity is found to degrade regularly with the increment in the addition level as a consequence of the induced permanent structural disorders-defects, intergranular grain boundary coupling interaction problems and non-superconducting barrier regions in the bulk Bi-2223 superconducting system. The vanadium addition brings also about the characteristic transition from over-doped state to under-doped state due to the suppression in the overlapping of Cu-3d and O-2p wave functions. The XRD results indicate that the vanadium addition leads to shift the characteristic peaks towards the larger/lower angles in terms of the peak positions in the reference data, enlarge the diffraction peak widths (line broadening of X-ray diffraction), appear or disappear new peaks, increase/decrease the average grain size, lattice cell parameters and superconducting phase fractions founded on the diffraction intensities. Based on the evidences, the presence of vanadium particles in the bulk Bi-2223 superconducting phase damages crucially the fundamental characteristic features. Moreover, it is found that characteristic two-stage (bulk genuine, $$T_{{\text{c}}}^{{{\text{mid}}}}$$ and coherence, $$T_{{{\text{co}}}}$$ ) transition temperatures decrease systematically with the addition level. On this basis, the presence of vanadium impurity in the system leads to degrade the stabilization of superconductivity in the small homogeneous clusters in the paths and especially effective electron–phonon coupling (bipolaron in the polarizable lattices) probabilities due to the reduction of hole trap energy per Cu ions in the valence band of system. Additionally, the results display that the vanadium particles affect negatively on both the dirty limit characteristic feature and gap coefficient of Bi-2223 ceramic compound as a result of the decrement in the minimum required energy for breaking up the cooper-pairs in the system. At the same time, the electrical resistivity curves enable us to develop a sensitive semi-empirical approach to find the possible highest onset critical transition temperature for the ideal crystallinity. The model founded on the crystallinity quality displays that the possible highest onset transition temperature is about 116.037 K ± 1.25587 K with R2adj = 0.948.

Effect of Vanadium (IV) Sulfate Particles Present in the Posolyte on the Anodic Current of a Vanadium Redox Flow Battery

Vanadium redox flow batteries (VRFB) are one of the most promising technologies for large scale energy conversion and storage (Cunha et al. 2014). Since it uses the same element in its four oxidation states (V(II)/V(III) and V(IV)/V(V) couples), its major advantage is the minimization of the cross-contamination problem observed in other RFBs. In addition, the fact that the electrolyte has an infinite regenerative capacity (Wang et al. 2015), makes this type of battery extremely rewarding on the economical point of view.However, their commercialization is hindered, among other reasons, by the limited quantity of stored energy (~ 40 kWh/m3), due to the low solubility of the vanadium salts (< 2 M), strongly influenced by the sulfuric acid concentration, generally used as supporting electrolyte: higher H2SO4 concentrations stabilize the V(V) species but decrease the solubility of the other salts (V(II), V(III) and V(IV)). Operating temperature also enhances the solubility of vanadium salts, inducing thereby an opposite behavior for the V(V) (solubility decreases with increasing temperatures) compared to the other valences. Therefore, the precipitation of vanadium species is considered to be an important problem for which a number of solutions has been proposed such as the use of a mixed H2SO4/HCl supporting electrolyte (Vijayakumar et al. 2013) and precipitation inhibitors (Skyllas-Kazacos et al. 2016). However, the understanding of the impact of the vanadium particles suspended in the electrolyte on the current was not yet addressed.Hence, the present work deals with the study of the impact of the presence of vanadium (IV) particles (VOSO4.5H2O powder) on the limiting current of the oxidation of V(IV) to V(V), using a classical three electrodes cell in which the working electrode is a rotating cylinder made of graphite. In addition, in order to insure an homogeneous distribution of the particles in the cell (avoid sedimentation), an additional stirring system, consisting of a cross-shaped stirrer is introduced at the bottom of the cell. Various kinds of measurements were achieved using a saturated V(IV) solution at 10 °C, in 3 M sulfuric acid: first, the effect of solid particles of VOSO4.5H2O powder was examined and then, comparatively the same experiments were performed using inert particles (glass spheres) having similar physical properties as the vanadium particles. In addition, the coupled effects of both the stirring provided from the rotating electrode and the stirring assured by the ‘cross-shaped stirrer’, on the magnitude of the current was also studied.The results show that the anodic limiting current of the V(IV) decreases, as the mass concentration of the solid particles increases. Higher apparent viscosity of the resulting mixture directly impacts the diffusion coefficient of the dissolved VO2+ species and limits the mass transfer. Moreover, the results do not show any positive effect of the presence of the solid particles (V(IV) or glass spheres) on the thickness of the diffusion layer (enhancement of the transfer of the dissolved VO2+ by some collisions between the solid particles and the electrode surface). Besides the study of the coupled effects of both stirring rates (electrode + additional stirrer) leads to some curious results on the evolution of the magnitude of the current, e.g. a ‘usual’ power law dependence until a complete independence, probably caused by a compensation of both motions in certain regimes. All these results were discussed.

Vanadium Dispersion Strengthening of Low-Carbon Pipe Steels

The research results of the nitrogen and vanadium influence on the microstructure, fine structure formation and mechanical properties of low-carbon steel pipe are considered. It is shown that it is possible to obtain cold-resistant mill products with strength classes from K48 to K60 with high (26–29%) percentage of elongation by dispersion hardening due to the precipitation of vanadium particles together with hardening of a manganese solid solution in the conditions of the Vyksa Metallurgical Plant casting and rolling complex.

Atmospheric pollution from ships and its impact on local air quality at a port site in Shanghai

Abstract. Growing shipping activities in port areas have generated negative impacts on climate, air quality and human health. To better evaluate the environmental impact of ship emissions, an experimental characterization of air pollution from ships was conducted in Shanghai Port in the summer of 2016. The ambient concentrations of gaseous NO, NO2, SO2 and O3 in addition to fine particulate matter concentrations (PM2.5), particle size distributions and the chemical composition of individual particles from ship emission were continuously monitored for 3 months. Ship emission plumes were visible at the port site in terms of clear peaks in the gaseous species and particulate matter concentrations. The SO2 and vanadium particle numbers were found to correlate best with ship emissions in Shanghai Port. Single-particle data showed that ship emission particles at the port site mainly concentrated in a smaller size range (&lt;0.4 µm), where their number contributions were more important than their mass contributions to ambient particulate matter. The composition of ship emission particles at the port site suggested that they were mostly freshly emitted particles: their mass spectra were dominated by peaks of sulfate, elemental carbon (EC), and trace metals such as V, Ni, Fe and Ca, in addition to displaying very low nitrate signals. The gaseous NOx composition in some cases of plumes showed evidence of atmospheric transformation by ambient O3, which subsequently resulted in O3 depletion in the area. Quantitative estimations in this study showed that ship emissions contributed 36.4 % to SO2, 0.7 % to NO, 5.1 % to NO2, −0.9 % to O3, 5.9 % to PM2.5 and 49.5 % to vanadium particles in the port region if land-based emissions were included, and 57.2 % to SO2, 71.9 % to NO, 30.4 % to NO2, −16.6 % to O3, 27.6 % to PM2.5 and 77.0 % to vanadium particles if land-based emissions were excluded.

Reinforcement of vanadium on the microstructure and properties of Sn-58Bi lead-free solder joints

The microstructure and the mechanical properties of the Sn-58Bi based composite solder joints reinforced by different content vanadium (V) particles were investigated. The results showed that the Sn-58Bi-0.4 V solder alloy with spreading area 52.51 mm2 exhibited an appropriate wettability. The microstructure of Sn-58Bi solder alloy consisted of rich Bi phase and rich Sn phase, and the spacing of Sn-rich phase was reduced from 2.13 μm to 0.98 μm by adding 0.4 wt% V particles. The intermetallic compounds (IMCs) layer of Cu/Sn-58Bi/Cu solder joint was presented as scallop shape, and the IMCs layers thickness of Cu/Sn-58Bi-xV/Cu (x = 0–1.0) solder joints was firstly increased to the maximum 0.95 μm and then decreased with increasing V content. The tensile strength and the shear strength of Cu/Sn-58Bi/Cu solder joint were 72.76 MPa and 38.44 MPa, then were reached the maximum 83.81 MPa and 42.81 MPa by Cu/Sn-58Bi-0.4 V/Cu solder joint, respectively. The tensile and the shear fracture morphologies of Cu/Sn-58Bi-xV/Cu (x = 0–1.0) solder joints with the brittle fracture mode were both presented as cleavage fracture, and a couple of dimples occur in the tensile and the shear fracture of Cu/Sn-58Bi-0.4 V/Cu solder joint.

Microstructural characterization of vanadium particles reinforced AA6063 aluminum matrix composites via friction stir processing with improved tensile strength and appreciable ductility

Abstract The reinforcement of ceramic particles in aluminum matrix composites (AMCs) restricts the plastic flow of the matrix and causes a loss in ductility. The reported research work demonstrates an improvement in tensile strength without losing appreciable ductility by reinforcing vanadium particles (~18 µm) into AA6063 AMCs by friction stir processing (FSP). Vanadium possesses a reasonable tensile strength (282 MPa) and higher elongation (35%). The composite microstructure was analyzed using optical microscope, scanning electron microscope and electron backscattered diffraction. Vanadium particles were dispersed homogenously in the aluminum matrix and the dispersion was consistent across the processed zone. There was no sign of interfacial reaction and an extremely fine grain structure was observed. Vanadium particles improved the tensile strength but retained considerable ductility of the composite. The causes for improvement in ductility and the features of fracture surface were presented.

Development of Vanadium‐Coated Carbon Microspheres: Electrochemical Behavior as Electrodes for Supercapacitors

AbstractVanadium‐coated carbon‐xerogel microspheres are successfully prepared by a specific designed sol–gel method, and their supercapacitor behavior is tested in a two‐electrode system. Nitrogen adsorption shows that these composite materials present a well‐developed micro‐ and mesoporous texture, which depends on the vanadium content in the final composite. A high dispersion of vanadium oxide on the carbon microsphere surface is reached, being the vanadium particle size around 4.5 nm. Moreover, low vanadium oxidation states are stabilized by the carbon matrix in the composites. The complete electrochemical characterization of the composites is carried out using cyclic voltammetry, chronopotentiometry, cycling charge–discharge, and impedance spectroscopy. The results show that these composites present high capacitance as 224 F g−1, with a high capacitance retention which is explained on the basis of the presence of vanadium oxide, texture, and chemistry surface.

Anticorrosion properties of textured substrates made of copper-based binary alloys

The tendency of some copper-based binary alloys to oxidize has been studied by the thermogravimetry method. It has been established that, apart from their perfect cubic texture and the high strength properties, substrates made of the Cu–Ni, Cu–0.4% Cr, and Cu–1.6% Fe alloys also possess better anticorrosion properties at the temperature of the deposition of the epitaxial layers (700°C) than the substrates of pure copper. In the alloys containing disperse particles of a second phase, the oxidation resistance decreases in the inverse proportion to the particle size. The Cu–0.6% V ribbon, in which the vanadium particles reach a size of several microns, was even less resistant to oxidation than the copper substrate; therefore, it cannot be used for the deposition of functional layers at elevated temperatures.