Elements Molybdenum Research Articles

Comparison of the Microstructure and Mechanical Properties of Ti-3573 and Ti-3873 Alloys after Cold Rolling and Aging Treatment

The novel titanium alloys were investigated in this article. The Ti-3573 and Ti-3873 titanium alloys were cold rolled and aged for different times at 650°C. The microstructure and mechanical properties of the samples were observed and measured, respectively. The results show that the mechanical properties of Ti-3873 alloys were better than those of Ti-3573 alloys. The cold rolling accelerated the α phase precipitation effectively. Stress-induced martensitic transformation was observed in both titanium alloys after cold rolling and aging treatment. Better aging strengthening effect can be obtained for the Ti-3873 titanium alloy which contains more molybdenum element, it is attributed to the role of Mo as β phase stable elemen. The tensile strength of Ti-3873 titanium alloy after aging for 3h reached the maximum value (1314MPa).

Characteristic features of molybdenum, copper, tungsten and rhenium accumulation in the environment

The article deals with the assessment of biogenic migration of molybdenum and other trace elements in ore and background conditions. The purpose of this study was to determine the specific features of copper and/or molybdenum accumulation rates in animals against the background of various tungsten and rhenium content levels in the environment and animal feeds, as well as possible metals incorporation into XO-XDH of cow milk. The field biogeochemical studies were performed in summer 2009, 2012, and 2018 in ore landscapes of W-Mo deposits (Tyrnyauz) and background areas of the North Caucasus with the selection of breeds, soils, natural water, plants, animal blood, and dairy products. For comparison, dairy products from the Moscow region were also examined. It was established that metals accumulated not only in soils but also in pasture plants. High content of molybdenum in the blood of cows in ore regions accompanied by a sharp decrease in the concentration of copper was noted. The concentration of studied metals in buttermilk in ore regions increased by 5–10 times in comparison with the control zone. When studying W-Mo ore landscapes of the North Caucasus (Tyrnyauz), the tungsten and rhenium were found to be capable of incorporation into the xanthine enzyme fractions (oxidase) in animals. This fact was discovered for the first time. In the case of an increase in the content of molybdenum and/or tungsten (rhenium) in the environment, the migration of the latter metals is significantly enhanced in ore conditions.

Effects of nitrogen element on microstructure and pitting corrosion resistance of duplex stainless steel welded joints

The microstructure, element distribution and pitting corrosion resistance of Gas Tungsten arc welding (GTAW) duplex stainless steel welded joints under 100% argon (Ar) and 98% Ar + 2% nitrogen (N2) shielding gas were studied by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electrochemical corrosion methods. These results show that the addition of N2 to the shielding gas promotes the formation of austenite (γ) phase in the weld joint. Also, the austenite phase distribution is dendritic and the ferrite (δ) and austenite phases in the heat-affected zone are no longer banded structures. Moreover, the austenite phase in the welded joint is enriched in nickel (Ni) and nitrogen (N) elements, while the ferrite phase is enriched in chromium (Cr) and molybdenum (Mo) elements. The pitting corrosion index (PREN) of the austenite/ferrite (δ/α) phase boundary is lower than that of δ and γ phases, which leads to their preferential corrosion. The appearance of chromium nitride (Cr2N) decreases the corrosion resistance of the weld seam and the heat affected zone. N2 in the 98% Ar + 2% N2 shielding gas can restrain Cr2N precipitation, increase the pitting corrosion index of secondary austenite structure (γ 2), and improve the pitting corrosion resistance of welded joints.

Singlet oxygen triggered by robust bimetallic MoFe/TiO2 nanospheres of highly efficacy in solar-light-driven peroxymonosulfate activation for organic pollutants removal

Sulfate-radical (SO4−) based Advanced Oxidation Process (SR-AOP), which is mainly generated from peroxymonosulfate (PMS) activation, is an excellent route for water treatment. Bimetallic nanoparticles have been widely applied in electronic, chemical, biological, and mechanical fields, etc.; however, few researchers have attempted to adopt bimetallic nanoparticles in environmental remediation. Further, in recent years, element molybdenum (Mo) has addressed much more environmental field attention than ever. Although singlet oxygen (1O2) generated commonly in SR-AOPs, its generation mechanism remains controversial. Hence, in this work, bimetallic MoFe/TiO2 nanospheres were rationally constructed via a facile two-step methodology. Undoubtedly, it exhibited superior performance for the degradation of organic pollutants (e.g., rhodamine, phenol, 4-chlorophenol and sulfadiazine) irradiated by simulated solar light. Both photo-generated electrons and transition metallic redox couples (i.e., Mo6+/Mo4+, Fe3+/Fe2+ and Mo4+/Fe3+) play vital roles in the PMS activation. Distinct from conventional SR-AOPs, sulfate radicals (SO4−), hydroxyl radicals (OH) and peroxymonosulfate radicals (SO5−) indeed participate in the transformation and generation of singlet oxygen (1O2). With the combination of DFT calculation, the Mo sites on the bimetallic MoFe (110) facet are more favorable to adsorb PMS molecules, then followed by the dissociation of PMS progressing on the Mo sites. Electrons transferring from the Mo atoms to the Fe atoms facilitated the adsorption of the negatively charged HSO5- anions, resulting in enhanced PMS activation efficiency. Considering its novelty and generation mechanism, this work highlights the mechanism of 1O2 generation from PMS reduction and oxidation simultaneously and furnishes theoretical support for further relevant studies.

Sustainable Management of Kidney Bean Plants by Soil Application of Humic Substances and Foliar Application of Molybdenum .

Only few publications focus on the effect of humic substances plus foliar spraying with molybdenum on plants. Therefore, the objective of this study was to determine the influence of some humic substances (i.e., potassium fulvate and humate as a single treatment or in a combination) and the foliar application of molybdenum element (i.e., 0.0 and 50 mg L-1 as ammonium molybdate) on kidney bean (Phasuolas vlugaris L.; variety Nebraska) plants. The field trial was carried out in a private farm at Tanah Village, El-Mansoura District, El-Dakahlia Governorate, Egypt during two consecutive growing seasons (2017 and 2018). The experimental design was a split-plot with three replicates. The findings showed that the combined treatment of potassium fulvate with potassium humate under foliar application of Mo at rate of 50 mgL-1 was the superior treatment for vegetative growth criteria i.e. fresh and dry weights of shoot and plant height, chemical constituents in leaves i.e. chl.a, chl.b, chl (a+b), N, P, K , Mo and NPK nutrients uptake at a period of 45 days from sowing as well as yield i.e. pods and seeds weights and nutritional elements concentration in seeds i.e. nitrogen, phosphorus, potassium, molybdenum and NPK nutrients uptake at harvest stage of kidney bean plants. While the lowest values of all aforementioned traits were recorded with untreated plants (without both humic materials and Mo). Also, available N, P and K in soil after harvesting kidney bean plants pronouncedly differed due to all studied treatments.

Alloy research issues for surface sealing of pipeline fittings

This article discusses chrome-nickel-silicon steel used for surfacing sealing surfaces of pipe fittings of chemical, petrochemical and power equipment. In order to increase the wear resistance of surfacing alloys, the effect of additional alloying of the deposited metal with boron, molybdenum and other elements on the service properties of this alloy is investigated. As a result of alloying, the resistance to scoring of deposited metal alloyed with boron and molybdenum increases by 1.5–2 times.

REDUCING THE INCIDENCE OF RIND CREASING OF “NAVEL" ORANGES BY FOLIAR APPLICATION OF AN ANTI-ETHYLENE AND SOME NUTRIENTS

The present study was conducted during 2017 and 2018 seasons on “Washington” navel orange trees to provide orange growers, with safe treatments that are applicable on field scale to reduce or prevent the incidence of rind creasing and to strengthen the structure of the albedo tissues by using calcium, molybdenum, or an anti-ethylene compound (AVG). The results of the present study indicated that ammonium molybdate (at 100 ppm) reduced creasing percentage. Moreover, the combination of AVG (at 50 ppm) plus ammonium molybdate m(at 100 ppm) reduced creasing percentage, rind thickness and rind EC percentage. Moreover, enhanced rind and juice nutrient contents especially molybdenum and sulfur elements.

Suppressing the lateral growth during HVPE-GaN crystallization in the c-direction

Different configurations of the growth zone were examined for crystallization of HVPE-GaN. The motivation for this work was to suppress growth in the lateral directions which appears on the seed edges during crystallization in the [0 0 0 1] direction. This phenomenon is a significant problem for growing thick GaN boules. Changes in the configuration involved placing molybdenum elements close to the growing crystal. Such a solution allowed to decrease the area of material deposited at the edges. The reason for this was examined with Computational Fluid Dynamics simulations. Distributions of reagents over the seed and the resulting supersaturation were examined. The value of the latter was lower near the edges of the crystal where the molybdenum elements were placed.

The Chemical and Isotope Composition of Nitrogen Thermal Groundwaters of the Kuldur Spa (Jewish Autonomous Region, Russia)

The results of the hydrogeochemical study of poorly mineralized thermal groundwaters from the Kuldur Spa (Jewish Autonomous Region, Russia) are reported. These groundwaters are distinguished by their high temperature (73°С), low TDS (up to 0.38 g/L), and alkaline environment (pH 9). The dominant cation is sodium, and the dominant anion is hydrocarbonate. The waters are enriched in fluorine, silicon, aluminum, tungsten, molybdenum, and several other anionic elements. Detailed data on the chemical and mineral composition of water-hosting (intrusive) rocks are provided and the sources of the major brine components in the groundwaters are revealed. The study of the associated gases shows that the major component of the gaseous phase (N2) is atmogenic, while CH4 and CO2 are biogenic. Argon and oxygen are derived from air as well, whereas helium is predominantly of the radiogenic crustal origin. The isotope characteristics of oxygen and hydrogen in the aqueous phase indicate the undoubtedly meteoric genesis of the groundwater with an extended circulation period. The results suggest that the thermal groundwaters of the spa are formed via penetration of meteoric waters to a depth of 4 km and heating to 100 °C. The dissolved chemical elements that form the brine phase come via the dissolution of host rocks; however, since the groundwater circulates within the rocky massifs of poorly soluble granitoids, respectively, the TDS of the groundwater remains low.

An evaluation of the supply risk for China's strategic metallic mineral resources

An important issue for ensuring a nation's economic security involves evaluating the supply risk of its strategic mineral resources. Considering the impact of strategic emerging industries on the supply risk of China's strategic minerals, this study establishes an indicator system for evaluating such risks. Specifically, using stochastic multi-criteria acceptability analysis for the ELimination Et Choix Traduisant la REalité TRI method, this study systematically evaluates the supply risk of 14 strategic metallic mineral resources in China from 2008 to 2017 and through 2025. The results indicate that: 1) From 2008 to 2017, the supply risk level of molybdenum and rare earth elements were low or low-to-medium, and those of 12 other minerals were high or medium-to-high; 2) For copper, gold, tungsten, molybdenum, antimony, and lithium, the supply risk level increased, and that for nickel decreased, while for iron, tin, chromium, and rare earth elements it irregularly fluctuated; and 3) The supply risk of chromium, molybdenum, lithium, and rare earth elements was influenced by potentially higher risk factors caused by poor substitutability and low recycling rate.

Characterization of Ti–6Al–(4V–7Nb–4Mo) Biomedical Alloys Produced by Powder Metallurgy Method

Pure titanium and titanium-based alloys are the most widely used metallic biomaterials in biomedical applications. At that, the Ti–6Al–4V alloy is considered as the most commonly exploited alloy among all alloys that contain titanium. However, it is known that the vanadium metal that constitute this alloy has a potential toxic effect. In this study, the powder metallurgy (PM) method was used for the production of pure-Ti, as well as Ti–6Al–4V, Ti–6Al–7Nb, and Ti–6Al–4Mo alloys. Niobium and molybdenum elements, one of the alloying metals, have been proposed as a substitution of vanadium due to its possible toxic effects. Produced samples were characterized by SEM, EDX, XRD, as well as microhardness, density, and Tafel extrapolation method. The analysis results showed that microstructure of pure titanium and titanium-based alloys differ. Besides, the XRD analysis showed that the phases of doped metals (Nb, V, and Mo) were found as Al0.23Nb0.07Ti0.70, Ti0.80V0.20, and AlMoTi3. Microhardness and Tafel extrapolation values were quite remarkable by comparing them to each other. The main important result of the research was obtained pure titanium and titanium alloys with homogeneous microstructure produced by the powder metallurgy method.

A new active NaVMoO6 cathode material for rechargeable Li ion batteries

Brannerite-type NaVMoO6 with vanadium (V5+) and molybdenum (Mo6+) elements in the highest valence states is synthesized by a sol-gel method using Na2CO3, NH4VO3, MoO3 and citric acid reagents. The results of X-ray diffraction (XRD) with Rietveld refinement and X-ray photoelectron spectroscopy (XPS) show that the obtained NaVMoO6 sample is single-phase. Novel electrode material (NaVMoO6) with layered structure is first utilized as cathode material for lithium ion batteries (LIBs). The NaVMoO6 electrode delivers reversible specific capacity of 126.4 mA h g−1 at 5 mA g−1 after 50 cycles. The stable structure of NaVMoO6 is corroborated by ex-situ XRD, suggesting that this material is considered as a prospective cathode for LIBs. This studying enriches the possibilities of molybdenum-based materials as cathodes for LIBs.

THE STRUCTURE OF PRODUCTIVITY OF SPRING WHEAT DEPENDING ON THE VARIETY AND FOLIAR TREATMENT WITH MANGANESE, COPPER AND MOLYBDENUM

The article presents the results of research on the structure of productivity of spring wheat depending on the variety and use of trace elements of manganese, copper, molybdenum and Ultramag Combi. It was found that the best productivity indicators were formed by the spring wheat variety Yoldyz. The optimal combination of microelements that positively affect the structure of spring wheat productivity has been established. The best indicators of the structure of the spring wheat yield of Tulaykovskaya 10 and Tulaykovskaya 108 varieties were formed when foliar treatment of crops with a paired mixture of copper and molybdenum with nitrogen, and Yoldyz varieties - manganese and copper, as well as manganese and molybdenum with nitrogen. Foliar treatment with a multi-component preparation Ultramag Combi, as well as separately applied nitrogen in amide form, was less effective.

Machine learning of mechanical properties of steels

The mechanical properties are essential for structural materials. The analyzed 360 data on four mechanical properties of steels, viz. fatigue strength, tensile strength, fracture strength, and hardness, are selected from the NIMS database, including carbon steels, and low-alloy steels. Five machine learning algorithms were applied on the 360 data to predict the mechanical properties and random forest regression illustrates the best performance. The feature selection was conducted by random forest and symbolic regressions, leading to the four most important features of tempering temperature, and alloying elements of carbon, chromium, and molybdenum to the mechanical properties of steels. Besides, mathematic expressions were generated via symbolic regression, and the expressions explicitly predict how each of the four mechanical properties varies quantitatively with the four most important features. The present work demonstrates the great potential of symbolic regression in the discovery of novel advanced materials.

Accelerated Transformation of Hot Deformed Austenite in SCM435 Steel

The element chromium and molybdenum delays the γ→α phase transition, while the deformation energy storage and high temperature diffusion can promote the γ→α phase transition process. The phase change of alloy structural steel SCM435 under different deformation temperature and cooling path after heating and holding at 1050°C was measured by a thermal simulator. The microstructure and hardness of the steel under various rolling processes were studied by using SEM and micro-hardness tests. The low deformation temperature (800~720°C) and the slow post-rolling cooling speed (1~0.3°C/s) were favorable for the γ→α phase change, where the phase microstructure showed the low hardness. As the isothermal temperature decreases, the microstructure changes from Pearlite (P)+ Ferrite (F) to P+ F + Martensite(M). The lower the isothermal temperature, the higher the martensite content in the structure, and the higher the hardness was. Both the low temperature deformation and 660°C isothermal treatment could quickly accelerate the γ→α transformation of SCM435. The fastest transformation temperature in this case for pearlite of SCM435 was 660°C, and the phase transition ended within 300s, which significantly shortened the time compared with the isothermal time in the low temperature zone.

Optimization of Heat Treatment Parameters of 25Cr–8Ni–4Mo–N Cast 5A Duplex Stainless Steel Using Thermodynamic Modelling and Taguchi Methodology

Duplex stainless steel (DSS) is having an equal fraction of ferrite and austenite. Chromium, Nickel, Molybdenum, and few minor alloying elements constitute a DSS system, which makes metallurgy of the system complex. Proper heat treatment is need of the hour when it comes to expecting desired properties from the material, subjected to a specific working environment. DSS is one of the favourite choices for oil and gas industries. This study focuses on optimizing the heat treatment parameters and heat treating the as-cast 5A DSS and investigating microstructural evolution of the material subjected to various quenchants such as brine, water, and polyethylene glycol. Heat treatment temperatures, quenching media, and the quenching time have been selected in accordance with ASTM standards. Thermocalc TCFE8 database is being used for understanding the material response to various heat treating temperatures.

Elaboration and pilot testing of a technology for production of sheet rolled products of cryogenic grade steels for liquidized natural gas storing

The liquidized natural gas (LPG) as well as other liquidized gases, as oxygen, nitrogen, ethylene etc. are widely used in the today’s world economy. A perspective of LPG and liquidized gases application presented, foreign and domestic experience in production of materials, used for manufacturing tanks and reservoirs, intended for storing and transporting of LPG, considered. Influence of chemical composition of cryogenic steels on resistivity to fragile destruction at negative temperatures studied. Influence of various alloying elements, including nickel, manganese, chrome, molybdenum and other elements on operating properties of cryogenic steels were also studied. Specialists of JSC “Ural Steel” together with scientists of JSC “NPO “CNIITMASH” elaborated a comprehensive technology of industrial production of plates of cryogenic steels. Based on literature data, domestic practice of designing and manufacturing cryogenic equipment, specifications of the required application plates were elaborated and approved. The rolling of plates of wide range of thickness of pilot heat 0H6 steel was carried out. At present, the thermal treatment modes of the 0H6 steel rolled products are being adjusted.

Metal-organic frameworks derived MMoSx (M = Ni, Co and Ni/Co) composites as electrode materials for supercapacitor

Abstract In this present paper, a novel layered multi-metal sulphide was reported as a positive electrode material with abundant electroactive sites and redox reaction centres. Molybdenum and sulfur elements were introduced into the metal-organic frameworks (M-MOF: M = Ni, Co and Ni/Co) to synthesize layered MMoSx by a hydrothermal method. The electrochemical performance comparison of MOFs and six electrode materials demonstrated that NiCoMoSx electrode materials had the best electrochemical performance and the highest specific capacitance. The highest specific capacitance could reach 2595 F g−1 at a current density of 1 A g−1. The NiCoMoSx electrode material also had an excellent cycle stability with a retention rate of 90.8% after 10,000 charge and discharge cycles. In addition, the as-assembled NiCoMoSx//AC assymmetric supercapacitor (ASC) device exhibited a maximum energy density of 48.2 Wh·kg−1 at a power density of 807.2 W kg−1, and the capacity retention rate after 10,000 charge and discharge cycles was 91.6%. This electrochemical performance indicated that this kind of material had a good market development prospect.

SYNTHESIS AND STUDIES OF SOME cis- MoO2(VI) COMPLEXES WITH NITROGEN DONOR MACROCYCLIC LIGANDS

According to what mention in research paper, the reaction of [MoO 2 (L)](acac) 2 with 1,3-diketones gives the formation of 1 MoO 2 (VI) complex of formulation [MoO 2 (L)](acac) 2 with a Schiff base, acquire from condensation of di-2-thienylethanedione with 2,3-diaminotoluene and four new complexes having formula [MoO 2 (ML)](acac) 2 . The each of the five dioxomolybdenum(VI) complexes synthesized were represented by thermal studies, elemental analyses, UV-Vis, molar conductance, IR and NMR and. The molybdenum metal has coordination number of 6. Each of the dioxomolybdenum(VI) complexes have geometry of octahedral arrangement. Distorted octahedral environment exist surrounding to molybdenum element in formed MoO 2 (VI) complexes. The ligand geometry was completed by two oxo O-atoms and four N-atoms. The synthesized complexes were show moderate activity versus S. aureus and S. typhi. The advancement inside the antibacterial activity being defined on the idea of chelation speculation.

Fractionation distribution of metal Al, Fe, Mn, and microbial population in acidic soil horizon

Acidic mineral soil generally has mild acidic to high acidic reaction or pH ⩽ 5.5, with very low exchangeable bases that can exchanged and rich in oxide as well as Al and Fe hydroxides. Acidized soil can lead to increased toxicity from aluminum, iron, and manganese element to the plants and deficiency of phosphorous, alkaline cation (calcium, potassium, and magnesium), and molybdenum element as well as soil microbial population. This study aimed to observe the fractionation distribution of metal aluminum (Al), iron (Fe), and manganese (Mn) and soil microbial population in acidic soil horizon. Al fraction parameters included exchangeable Al (Al-exc), non-crystalline Al (Al-o), inorganic non-crystalline Al (Al-po), Organically Bound Al (Al-p), Low- and Medium- Stability Complexes with Organic Matter (Al-Cu) and High-Stability Complexes with Organic Matter (Al-pCu), exchangeable fractionation of Fe and Mn (Fe/Mn-exc), Fe and Mn from Bound to Carbonates/Acid- extractable, Bound to Fe-Mn Oxides/Reducible, Bound to Organic Matter Fe Mn/Oxidizible, Fe- Mn Residual and soil microbial population (total microbes and Acidithiobacillus bacteria). The results, distribution of Al fraction on the upper horizon of Jasinga and Lebak were dominated by stabilized organic amorphous Al fraction with fluctuative decrease of organic matter (Al-pCu), while the lower horizon tended to be inorganic amorphous Al (Al-op). The fractionation distribution of Fe fractionation on Jasinga and Lebak was dominated by Oxidizible Fe fraction. Mn fraction distribution on Jasinga and Lebak were dominated by Mn-residual fraction in each acidic soil horizon. The total population of Microbes and Acidithiobacillus.sp in each soil horizon decreased along with the alteration of soil chemical properties in each soil depth horizon.