Low Vanadium Content Research Articles

Constructing highly active vanadyl species for efficient selective catalytic reduction of NOx

Vanadia-based catalysts have been commercially applied for selective catalytic reduction with NH3 of NOx (NH3-SCR). Considering the biotoxicity of V2O5, V-based catalysts are demanded to exhibit high catalytic activity with low V2O5 loadings. However, at low vanadium contents, surface VOx primarily present in the form of monomers, which show poor low-temperature activity. Here, efficient low-vanadium-loading catalysts were designed via constructing highly reactive polymeric vanadyl species by introducing disparate forms of niobia species. Niobia species were found to promote the polymerization of surface VOx, and the disparate forms of niobia species had a key influence on the formation of polymeric vanadyl species. Crystalline Nb2O5 promoted the formation of polymeric vanadyl species, induced by a structural effect. By contrast, uniformly dispersed niobium species on the surface of a Nb-Ti-O solid solution support served as new anchoring sites for VOx and promoted a greater extent of polymerization of VOx species via electronic interactions among V, Nb and Ti. Ultimately, Nb-Ti-O solid solution-supported V2O5 exhibited much higher low-temperature reaction rates than TiO2-supported Nb2O5 and V2O5 due to more polymeric vanadyl species. This study provides new methods to design low-vanadium-loading catalysts, offering new perspectives for the modification of transition metal oxides to design efficient catalysts.

Molecular Dynamics Simulation of the Interaction between Dislocations and Iron–Vanadium Precipitates in Alpha Iron: Effect of Chemical Composition

In this study, molecular dynamics simulations were employed to study the interaction between dislocations with Fe-V precipitate with different vanadium concentrations. Increasing the vanadium concentration in the precipitate results in a strong interaction between the dislocations and the precipitate, and the dislocation line bows out more as a result of increasing the energy of the dislocation line, and the critical stress needed for depinning the dislocations increases. However, at a low vanadium concentration (1:3 atomic ratio) the dislocations cut through the precipitate without changing the speed. An increasing vanadium concentration not only affects the dislocation shape and movement speed, but also affects the configuration of the junction between the a/2[111] and a/2[100] dislocations, and the void formation after the cutting process. The formation of strong junctions and a high number of voids locks the a/2[111] dislocation motion, and increases the strength of the alloy. The results of the radial distribution function before and after the cutting process show that the structure of the precipitate changes from crystalline to amorphous, and the degree of amorphization decreases with an increasing vanadium concentration.

SR Spectroscopy in Geochemical Studies of Asphaltenes of Crude Oils from Tatarstan Oil Fields

ESR spectra of asphaltenes from a series of crude oils from the Devonian and Carboniferous deposits of the South-Tatar Dome in Tatarstan with low vanadium content and of vanadiferous crude oils from deposits of the Melekess depression in Tatarstan are analyzed. For asphaltenes from Devonian oils, the correlation between the concentrations of stable free radicals (SFR) and vanadyl complexes (VCs) has direct trend, whereas for asphaltenes from Carboniferous oils the trend is inverse. Taking into account the previously revealed inverse trend for asphaltenes of vanadium-enriched highly viscous crude oils [1], the opposite trends in SFR–VC correlations (direct and inverse) suggest different structures of asphaltene molecules in oils with different vanadium content and, correspondingly, different sources and conditions of the formation of oil deposits. Specific features of the ESR characteristics of asphaltenes of core and extractable oils and of oils from Devonian and Carboniferous deposits are revealed.

Ethylene Polymerization over Supported Vanadium-Magnesium Catalysts with Different Vanadium Content: The Effect of Hydrogen on Molecular Weight Characteristics of the Produced Bimodal Polyethylene

Data are presented on the activity of supported vanadium-magnesium catalysts (VMCs) with different vanadium content in ethylene polymerization and the molecular weight characteristics of the produced polyethylene. The VC1 catalyst, with a very low vanadium content (0.12 wt.%), showed a sixfold higher activity per unit weight of vanadium than the VC2 catalyst with a high-vanadium content (4.0 wt.%). Additionally, the total activity of VC2 (kg PE/g cat·h) was fivefold higher when compared to VC1. The introduction of hydrogen in polymerization leads to a considerable decrease in the activity of both catalysts. The polyethylene obtained in the presence of hydrogen over both catalysts has a broad bimodal molecular weight distribution (MWD) with a distinct shoulder in the high-molecular region (Mw ≥ 106 g/mol). Decomposition of the MWD curves of bimodal polyethylene into two fractions (high- and low-molecular fractions) made it possible to determine for the first time the ratio of the reaction rate constants of chain transfer with hydrogen (KtrH) and polymer chain propagation (Kp) for two groups of the VMC active sites producing low- and high-molecular fractions of bimodal polyethylene.

Vanadium recovery from spent iron sorbent used for the treatment of mining-influenced water

Vanadium was recovered successfully from spent iron sorbent (ferric oxyhydroxide, CFH-12) using a two-step process including alkaline leaching and precipitation with CaCl2. The spent CFH-12 was collected from a field study in which a filter system was used to remove vanadium from mining-influenced water (referred to as MIW-treated CFH-12). Fresh CFH-12 was treated with synthetic vanadium solution (SVS-treated CFH-12) to compare the recovery process with the field study. First, a full factorial design was performed to optimize the precipitation process using synthetic leaching solution. The optimal conditions were found to be two times the theoretical dosage of CaCl2, a precipitation temperature of 60°C, and a precipitation pH of 12.7. Vanadium desorption from the spent sorbents was conducted using 1 M NaOH, a contact time of 30 minutes and a CFH-12 solid-to-liquid ratio of 0.15 kg/L. The results revealed that vanadium could be efficiently precipitated from the leaching solution of MIW-treated CFH-12 and SVS-treated CFH-12. A higher dosage of CaCl2 was required to recover vanadium from MIW-treated CFH-12 due to the complexity of the leaching solution, which resulted in a lower vanadium content in the product. XRD analysis showed that the product recovered from SVS-treated CFH-12 mainly contained Ca5(VO4)3OH and a small amount of CaCO3. TEM images revealed that the calcium vanadate hydroxide particles were round in shape, about 0.2–0.4 µm in size and formed aggregates. The product recovered from MIW-treated CFH-12 contained amorphous calcium vanadate and crystalline Ca(OH)2. XPS analysis confirmed that vanadium existed as V5+ in all of the recovered products.

A Comparative Analysis of Vanadyl Porphyrins Isolated from Heavy Oil Asphaltenes with High and Low Vanadium Content

A Comparative Analysis of Vanadyl Porphyrins Isolated from Heavy Oil Asphaltenes with High and Low Vanadium Content

A Comparative Analysis of Vanadyl Porphyrins Isolated from Resins of Heavy Oils with High and Low Vanadium Content

The composition of purified vanadyl porphyrins recovered from the resins of heavy oils possessing high and low vanadium contents was investigated. Vanadium content in the resins of the heavy oils under study differs by a factor of ca. 15. To recover and purify vanadyl porphyrins from the resins, extraction by N,N–dimethylformamide (DMF) with subsequent two-stage column chromatography on silica gel and sulfocationite were employed. The change of structural-group composition and content of vanadyl porphyrins in the products obtained at each stage was evaluated using Fourier IR and UV-Vis spectroscopy. Analysis of the purified vanadyl porphyrins using MALDI mass spectrometry determined distribution of their most abundant types (etio- and DPEP) and identified C27–C39 homologs for the resins possessing high vanadium content and C28–C39 homologs for the resins with low vanadium content.

Investigation of the microstructure and mechanical properties of Ti–6Al–4V repaired by the powder-blown underwater directed energy deposition technique

Underwater directed energy deposition (UDED) is a promising technology for on-site maintenance and repair of underwater structures. In this study, the damage zone on a Ti–6Al–4V plate was successfully repaired by UDED and no obvious internal defects were observed. The mechanisms of the special underwater thermal behaviors influencing the microstructural formation/evolution process and the resultant mechanical properties of Ti–6Al–4V repaired by UDED were systematically investigated by experimental and simulation methods. Compared with that prepared by in-air directed energy deposition (DED), the sample repaired by UDED presented the following differences: (1) The cooling rate was large and the heat accumulation of the sample was low during UDED due to the rapid heat dissipation by water and gas curtain gas. (2) The sample repaired by UDED was dominated by fine acicular martensite α′ with a high density of dislocations due to the weak intrinsic heat treatment (IHT), while the intensified IHT involved in DED provoked the significant decomposition of α′ into α and β film. (3) The weak IHT during UDED resulted in the formation of thin β films with a low vanadium content. The intensified IHT during DED promoted the diffusion of vanadium atoms and the coarsening of β films. (4) The average microhardness of the sample repaired by UDED (379 ± 15 HV) was higher than that repaired by DED (359 ± 11 HV). The sample repaired by UDED exhibited relatively poor ductility and low toughness due to the presence of acicular martensite α′. This work can provide an important foundation and useful guidance for tailoring the microstructure and properties of titanium alloys repaired by UDED in underwater environments.

Comparative efficacy of raw and HNO3-modified biochar derived from rice straw on vanadium transformation and its uptake by rice (Oryza sativa L.): Insights from photosynthesis, antioxidative response, and gene-expression profile

Low concentrations of vanadium (V) are essential for various plant species but it becomes toxic to plants, animals, and humans at high levels. A significant amount of V is currently being emitted into the atmosphere due to intensified industrial processing. Therefore, this study aimed at evaluating the effect of raw (BC) and HNO3-modified biochar (OBC) derived from rice straw on growth, photosynthetic assimilation, relative chlorophyll content, SPAD index, ion leakage, enzyme activities, hydrogen peroxide (H2O2), bioavailability and V uptake by rice in a laboratory-scale experiment. Characterization of OBC and BC by FTIR (Fourier transform infrared spectroscopy), SEM (scan electron microscopy), BET (Brunauer–Emmett–Teller), elemental analysis, and z-potential revealed a substantial difference between both of them. The V-stress significantly reduced the rice plant growth, biomass yield, chlorophyll parameters, root length and surface area. Under V-stress conditions, root accumulated more V than shoots and OBC significantly improved the above-mentioned parameters, while, decreasing hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels in plants. The antioxidant function and gene expression levels induced by V-stress and OBC application further increased the expression profile of three genes (SOD, POD, and CAT) encoding antioxidant enzymes and one metal-tolerant conferring gene (OsFSD1). In summary, these results demonstrated the critical role of OBC in mitigating the detrimental effects of high V-stress on rice growth and enhancing plant defence against V-stress.

THERMODYNAMIC AND ELECTROCHEMICAL STUDY OF VANADIUM SOLUTIONS: TOWARDS VANADIUM RECOVERY FROM A SPENT CATALYST

Due to the low abundance of vanadium in nature (about 135 g/t), the feasibility to recover it from industrial wastes has highly attracted scientific and technological attention. The main recovery routes reported are associated with chemical or thermochemical processes. However, the electrochemical recovery of vanadium from industrial wastes has been poorly investigated. In this work, a thermodynamic and electrochemical study for the possible vanadium recovery from a spent catalyst generated in the petrochemical industry was conducted. The study was divided into two stages using low vanadium concentrations. In the first stage, the recovery of vanadium was possible in its V4+ state at low reduction potentials, whereas for the second stage, cyclic voltammetry was used to calculate the diffusion coefficient and the heterogeneous velocity coefficient of the V5+/V4+ redox pair. The obtained values are similar to those reported in the literature for aqueous solutions at high vanadium concentrations and would allow the design of the system at large scale. This report aims to set the conditions for the possible vanadium recovery from a spent catalyst by means of electrochemical processes, although the optimization of such conditions must be further explored.

Tailoring the vanadium/proton ratio of electrolytes to boost efficiency and stability of vanadium flow batteries over a wide temperature range

Fast capacity decay and narrow temperature window still hinds the practical application of vanadium flow batteries (VFB). Optimization the electrolyte composition is an effective strategy to realize the stable operation of VFB. Herein, we introduce the concept of V/H ratio (vanadium ion to proton concentration ratio) in electrolyte to explore the vanadium concentration impact on overall performance of VFB. Theoretical analysis and experimental results indicate that reducing the V/H ratio is beneficial to obtain higher efficiency and better cycle stability over wide temperature (-15 °C ~ 55 °C). Meanwhile, during long-term operation, a lower V/H ratio electrolyte can achieve higher electrolyte utilization rate and deliver higher capacity despite the lower theoretical capacity density. Unlike previous studies that focused on increasing the vanadium concentration to obtain a higher theoretical capacity density, our techno-economic assessment clearly demonstrates that a relatively low vanadium concentration (i.e. 1.0–1.2 M) is more suitable for VFB, because safer, cheaper and more stable operation is particularly important for large-scale energy storage.

Metallogenesis of the Rhyacian Lavra Velha gold-rich IOCG deposit in the São Francisco Craton, Brazil

• The Lavra Velha deposit represents a new gold-rich IOCG mineralization at the São Francisco Craton . • The gold mineralization is associated with a hydrothermal breccia system with co-existing iron oxides and sulfides. • IOCG mineralization is related to the Rhyacian period of the northern São Francisco Craton. • Mineralization is marked by decreasing temperatures from the bottom to the top of the deposit. Lavra Velha is a newly discovered Rhyacian IOCG deposit in the northern portion of the São Francisco Craton, in the Bahia state of NE Brazil. Gold and copper mineralization is hosted by epigenetic hydrothermal breccia with large amounts of iron oxide. Multiple phases of breccia formation and hydrothermal alteration caused zoning from the base to the top of the deposit. The alteration is mainly characterized by hydrothermal calcite-epidote-magnetite, tourmaline-chlorite-magnetite, and sericite-hematite hydrothermal alteration styles. Tourmaline and chlorite chemistry indicates that low temperature alkaline fluids had variable Fe 2+ , Mg, Al, and Na contents throughout the evolution of the breccia complex. Magnetite and hematite display low vanadium content (≤0.24 wt%) and very low titanium content (≤0.06 wt%). The sulfide minerals are pyrite (with up to ~ 3 wt% Co), chalcopyrite, bornite, arsenopyrite, and covellite, in decreasing order of abundance. Coarse muscovite that is related to the latest stages of breccia displays a high barium content with an average of ≥ 1.27 wt%. Isotopic compositions of carbon and oxygen in calcite from the calcic breccia indicate that early mineralizing fluids were derived from a mixed magmatic/non-magmatic reservoir (δ 13 C ~ −2‰ and δ 18 O from 9.95 to 13.09‰ in calcite). The sulfur isotopic compositions of chalcopyrite and pyrite demonstrate that sulfur in the mineralized breccia was derived from cooling magmas that underwent weak contamination from oxidized fluids or host rocks (δ 34 S from 2.22 to 3.89‰). New U-Pb zircon ages indicate that mineralization occurred at approximately 2100 Ma, coeval with tourmaline-bearing porphyritic granite dikes that yield ages of 2098 ± 8 and 2112 ± 12 Ma respectively. Despite being considered a small deposit in relation to known reserves, Lavra Velha may be the first IOCG deposit recognized in the São Francisco Craton, particularly in the Gavião Block. Thus, it represents an important indicator for future precious and base metal exploration in the São Francisco Craton.

Toxic effects induced by vanadium on sea urchin embryos

Vanadium, a naturally occurring element widely distributed in soil, water and air, has received considerable interest because its compounds are often used in different applications, from industry to medicine. While the possible medical use of vanadium compounds is promising, its potential harmful effects on living organisms are still unclear. Here, for the first time, we provide a toxicological profile induced by vanadium on Paracentrotus lividus sea urchin embryos, reporting an integrated and comparative analysis of the detected effects reflecting vanadium-toxicity. At the morphological level we found a dose-dependent induction of altered phenotypes and of skeletal malformations. At the molecular levels, vanadium-exposed embryos showed the activation of the cellular stress response, in particular, autophagy and a high degree of cell-selective apoptosis in a dose-dependent manner. The stress response mediated by heat shock proteins seems to counteract the damage induced by low and intermediate concentrations of vanadium while the high cytotoxic concentrations induce more marked cell death mechanisms.Our findings, reporting different mechanisms of toxicity induced by vanadium, contribute to increase the knowledge on the possible threat of vanadium for marine organisms and for both environmental and human health.

Titanium Vanadium Oxide Thin Films Prepared by Thermal Oxidation of Titanium-Vanadium Alloy as Photocatalyst for Methylene Blue Degradation under Visible Light

In this work, titanium-vanadium oxide composite thin films were prepared by thermal oxidation of vanadium and titanium metallic alloys, at 500 °C under air atmosphere. The metallic alloys, with different vanadium contents, were obtained by co-sputtering of vanadium and titanium targets on glass and silicon substrates. The films were characterized by means of scanning electron microscopy (SEM), x-ray diffraction, Raman spectroscopy, infrared spectroscopy, x-ray photoelectron spectroscopy, and UV–Vis spectroscopy. In addition, photodegradation of methylene blue (MB) in aqueous solution, on these composite films, under visible light, was also evaluated. SEM images show nanostructured films with nanospherical or nanobaranched surface morphologies. Furthermore, the results reveal that at low vanadium (V) content, the films consist of one or mixture of amorphous phases (TiVOx or TiOx plus VOx, or both). In the case of films with higher V content, two separated phases, namely V2O5 and amorphous TiOx are obtained. The UV–Vis analyses demonstrate a redshift of optical absorption over a broad band of optical frequencies for films with high V content. Furthermore, these films manifested a good catalytic activity toward MB degradation with degradation rate of 78% after 120 min of visible light irradiation. Such composite thin films can be promising not only for photocatalytic applications, but also for photonic and sensing devices.

Study of rail steel alloying by chrome and vanadium effect on dissociation of overcooled austenite

To determine weldability and quality of a rail welded joint, information on kinetics of the rail steel overcooled austenite transformation is high importance. Thermo-kinetic diagrams of overcooled austenite dissociation of steels Э76ХФ, Э76ХАФ and Э76Ф, built based on results of dilatometric, metal science and durometric tests of rail steel samples. It was shown, that increase of chrome content in steels Э76Ф and Э76ХФ composition from 0.09 to 0.39% results in expanding of dissociation area of overcooled austenite at temperature scale for ferrite-cementite mixture and increasing of resistivity of the overcooled austenite against dissociation in the area of ferrite-cementite mixture formation. This can be characterized as decrease of critical quenching velocity from 100 to 30 °С/sec. It enables to obtain structural states of higher hardness at cooling with velocities in the area of 0.1−30 °С/sec. It was established, that increase of vanadium content from 0.04 to 0.07% does not cause quality changes at the thermo-kinetic diagram of overcooled austenite dissociation. However, it known, that vanadium is a strong carbide-formation element, which combines with carbon at low cooling velocities and removes it out of the solid solution. Due to this effect, sample of steel Э76ХФ with lower vanadium content at cooling with velocities from 0.1 to 10 °С/sec, had somewhat higher hardness level comparing with steel Э76ХАФ sample. Increase of chrome content in alloy content results in an increase of temperature of austenite formation completion at heating from 760 to 774 °С, while the temperature of martensitic transformation commencement at that remains practically unchanged at the level of 230 °С. In steels Э76ХФ and Э76ХАФ in the chemistry of which chrome was added in the amount of 0.37−0.39%, after cooling with velocities of 1 °С/sec and lower, apart from ferrite-carbide mixture of perlite type, formation of redundant ferrite with a volume share of 4−5% was observed as a result of overcooled austenite dissociation. However, in a steel Э76Ф sample, the content of which has chrome at the level of 0.09% at close content of carbon, after cooling in an analogue range of velocities, a ferritecarbide mixture of perlite type is formed with a slight trace of redundant ferrite in the structure as a result of overcooled austenite dissociation.

Investigation of vanadia-alumina catalysts with solid-state NMR spectroscopy and DFT.

In this work, isolated surface sites of vanadium oxide on the alumina surface were modeled and compared to experimental data obtained with 51V Solid-State Nuclear Magnetic Resonance (SSNMR) spectroscopy. The geometry of the centers on the (100), (110), and (111) planes of the spinel structure and (010) monoclinic alumina was modeled using density functional theory (DFT); their 51V NMR parameters were calculated using the Gauge-Including Projector Augmented Wave (GIPAW) method. The comparison of the simulated theoretical spectra with the experimental ones made it possible to find the sites that are likely present on the surface of real catalysts. The minimum energy pathways of propane oxidative dehydrogenation to propene were calculated for the dioxovanadium site in order to estimate its activity.

Vanadium doped layered copper-chromium sulfides: The correlation between the magnetic properties and XES data

X-ray emission spectroscopy and static magnetochemistry study of CuCr1-xVxS2 (x = 0 ÷ 0.40) was carried out. The atom charge were estimated using the core-level S, V, Cr and Cu(Kα)-lines energy. The additional data on the electron density distribution on the vanadium and copper atoms were studied analyzing the V(Lα) and Cu(Lα,β) spectra fine structure features. The charge distribution in the CuCrS2 matrix was found to be Cu+Cr3+(S2−)2. In the case of low vanadium concentrations x < 0.15 both Cu+Cr3+(S2−)2 and Cu0+δCr(4−δ)+1-xV(4−δ)+x(S2−)2 (δ→0) charge/magnetic configurations were found. The charge distribution for solid solutions doped with concentration x = 0.15 ÷ 0.40 was described as Cu+Cr3+1-xV3+x(S2−)2. The obtained data on the charge/magnetic configurations is in good agreement with the magnetochemical measurements results. The oxidation state changes could be due to the defectness caused by intercalation of the vanadium atoms into the copper sublattice.

Soil vanadium(V)-reducing related bacteria drive community response to vanadium pollution from a smelting plant over multiple gradients

The mining and smelting of navajoite has resulted in a serious vanadium pollution in regional geological environments and significant influence on soil microorganisms. However, the core microbiome responsible for adjusting community response to vanadium pollution and the driving pattern have been kept unclear. In this study, a suite of surface and profile soil samples over multiple gradients were collected in four directions and distances of 10–2000 m from a vanadium smelting plant in Panzhihua, China. The indigenous microbial communities and vanadium(V)-reducing related bacteria (VRB) were profiled by 16S rRNA gene high-throughput sequencing technique. Five VRB were detected in the original collected soil samples including Bacillus, Geobacter, Clostridium, Pseudomonas and Comamonadaceae based on high-throughput sequencing data analysis, and their abundances were significantly related with the content of vanadium. Low vanadium concentration promoted the growth of VRB, while high vanadium concentration would inhibit VRB multiplication. The Gaussian equation could be used to quantitatively describe the nonlinear relationship between VRB and vanadium. Network analysis demonstrated that the microbial communities were significantly influenced by VRB assemblage, and 1.32–52.77% of microbes in the community showed a close association with VRB. A laboratory incubation experiment also confirmed the core role of VRB to drive community response to vanadium pressure.

Vanadium-Substituted Phosphomolybdic Acids for the Aerobic Cleavage of Lignin Models—Mechanistic Aspect and Extension to Lignin

This work deals with the aerobic oxidative cleavage of C-C and C-O bonds catalyzed by the Keggin-type phosphovanadomolybdic acid (H6[PMo9V3O40], noted H6PV3). The latter was synthesized by an adapted hydrothermal procedure classically used for lower vanadium content and was tested as a catalyst for the aerobic cleavage of 2-phenoxyacetophenone (noted K1HH) and 1-phenyl-2-phenoxyethanol (A1HH) used as two lignin models. The operative conditions (solvent, catalytic loading, etc.) were adjusted on K1HH and extrapolated to A1HH. The cleavage of the alcohol model required more drastic conditions and therefore further optimization. Preliminary attempts on an Organosolv wheat straw lignin were performed too. From the kinetic study, high performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry (GC-MS) data, a mechanism of the cleavage of both models was proposed.

Electrodeposition of titanium\u2013vanadium alloys from chloride-based molten salts: influence of electrolyte chemistry and deposition potential on composition, morphology and microstructure

In the present study, we demonstrate co-deposition of titanium and vanadium from a eutectic LiCl–KCl electrolyte enriched with VCl3 and TiCl2 at 700 K. While the addition of metallic titanium to the electrolyte caused vanadium depletion by a displacement reaction, metallic vanadium addition created and stabilized divalent vanadium ions in the melt, which are supposed to positively affect the deposition process. Various electrochemical experiments were carried out with different electrolyte concentrations, and a relationship between applied potential, electrolyte concentration and composition of the deposit was established. The composition and the morphology of the obtained deposits were strongly affected by the electrolysis conditions. Electrodeposited vanadium-rich Ti–V alloys were found to grow as dendrites, whereas the titanium-rich alloys exhibited a dense cauliflower-like surface morphology. In contrast to deposits of the single elements, which are composed of comparably large faceted crystals, the Ti–V alloys obtained in this study were very fine grained, especially those with vanadium contents around 10–15 at%. Transmission electron microscopy revealed that, depending on the composition of the deposit, either a biphasic α + β microstructure in the case of low vanadium contents or β-(V,Ti) with small amounts of ω phase for high vanadium contents were found.Graphic abstract