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Acta Geologica sinica(English Edition) 2014年第3期88卷 845-853页

作者： Raju v.s.PERUMALA Roland K.W.MERKLE National Geophysical Research Institute PO Box 724 Hyderabad India (Council of Scientific and Industrial Research) Department of Geology University of Pretoria

Hogbomite,a rare exotic mineral,is found to be associated with the vanadiferous-titaniferous （v-Ti） bearing magnetite bands at Bhakatarhalli,Nuggihaifi greenstone belt,western Dharwar Craton,*** report on a second occurrence of hogbomite from the Dharwar craton in Karnataka,which is the sixth documented occurrence of this mineral from *** evaluate the chemical characteristics of hogbomite and associated Fe-Ti-minerals in an attempt to identify its formation as a primary hydrothermal mineral in a metamorphosed magnetite *** report here the presence of hogbomite as a complex oxide of Fe,Mg,Al and Ti with accessory of Zn,v and *** studies suggest the （v-Ti） bearing magnetite （Mt） contain spinel,hogbomite,chlorite,martite,ilmenite （Ⅱ） and minor amounts of *** hogbomite displays euhedral to subhedral textures,and is up to 250 μm along the grain boundaries of magnetite and *** the samples studied,hogbomite is prismatic,irregular and elongated in *** genesis of hogbomite in veins between magnetite and ilmenite implies its precipitation from fluids without involving complicated *** models were proposed for the formation of hogbomite; however,the subject is still debatable.

关键词： Hogbomite western Dharwar craton vanadium magnetite EPMA India

Fabrication and characterization of Ti6A14v/TiB2-TiC composites by powder metallurgy method

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Rare Metals 2017年第10期36卷 806-811页

作者： M. Anandajothi s. Ramanathan v. Ananthi P. Narayanasamy Department of Manufacturing Engineering Annamalai University Chidambaram Tamil Nadu 608 002 India Physics section Faculty of Engineering and Technology Annamalai University Chidambaram Tamil Nadu 608 002 India Department of Mechanical Engineering Kamaraj College of Engineering and Technology Virudhunagar Tamil Nadu 626 001 India

Titanium matrix （Ti6Al4v） composites rein- forced with TiB2 and TiC were produced through powder metallurgy method. The effect of addition of both TiB2 and TiC with different contents （2.5 wt%, 5.0 wt% and 7.5 wt%） on the density, microstructure and hardness properties of titanium matrix was investigated. The size distributions of the matrix alloy and reinforcement particles were measured by particle size analyzer. Microhardness of the sintered composites was evaluated using vickers＇s hardness tester with a normal load of 3 N and a dwell time of 10 s. Ti6Al4v alloy and Ti6Al4v/TiB2-TiC composites were characterized through X-ray diffraction （XRD） and field emission scanning electron microscope （FEsEM） equipped with energy-dispersive spectrometer （EDs）. The addition of TiB2 and TiC particles enriches the properties of Ti6Al4v alloy. The sintered Ti6Al4v/TiB2-TiC composite features a dense and pore-free microstructure with varying TiB2 and TiC particle distribution in the metal matrix. The results of this study show that the development of new phases plays a significant role in the properties of these composite materials.

关键词： Ti6Al4v TiB2 TiC Microstructure

static and cyclic oxidation of Nb-Cr-v-W-Ta high entropy alloy in air from 600 to 1400℃

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Journal of Materials science & Technology 2020年第3期38卷 189-196页

作者： s.K.varma Francelia sanchez sabastian Moncayo C.v.Ramana Department Metallurgical Materials and Biomaterials EngineeringThe University of Texas at El PasoEl PasoTX79968-0520USA Center for Advanced Materials Research(CMR) The University of Texas at El PasoEl PasoTX79968-0520USA

An oxidation resistance study has been made on Nb-Cr-v-W-Ta high entropy alloy in a range of temperature from 600 to 1400℃in *** oxidation study has been performed for either(a)12 or 24 h of heating time or(b)3 or 10℃/min heating rates to the desired oxidation *** oxidation study conducted for three and a half days has been conducted at 600,700,and 800℃using 12 h of heating *** alloy can withstand the cyclic oxidation process with only a reasonable loss of *** identification of oxides indicates crystals of W and Ta oxides in cylindrical form while Nb and Cr oxides show a nodular or granular morphology at both 1000 and 1200℃while and additional of oxide of v in whisker forms at 1200℃.

关键词： High entropy alloys Nb-Cr-v-W-Ta Microstructures Oxidation

Improved strength and ductility of high alloy containing Al–12Zn–3Mg–2.5Cu alloy by combining non-isothermal step rolling and cold rolling

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International Journal of Minerals,Metallurgy and Materials 2017年第2期24卷 179-185页

作者： v.v.Ravikumar s.Kumaran Department of Metallurgical and Materials Engineering National Institute of TechnologyTamil Nadu 620015India

Al-12Zn-3Mg-2.5Cu alloy was prepared using a liquid metallurgy route under the optimized conditions. A sample cut from the ingot was rolled non-isothermally from 400℃ to 100℃ in 100℃ steps, with 15% reduction in thickness; it was then cold rolled isothermally at room temperature for 85% reduction. The cold-rolled alloys were characterized by electron microscopy, hardness test, and tensile test to elucidate their structural evolution and evaluate their mechanical behavior. In the results, the cast alloy consists of a-aluminum and various intermetallic compounds. These compounds are segregated along the grain boundaries, which makes the alloy difficult to roll at room tem- perature. The combined effect of non-isothermal step rolling and cold rolling results in the nano/microsized compounds distributed uniformly in the matrix. The hardness is substantially increased after rolling. This increase in hardness is attributed to the ultra-fine grain size, fine-scale intermetallic compounds, and structural defects （e.g., dislocations, stacking faults, and sub-grains）. The ultimate tensile strength of the rolled alloy is approximately 628 MPa with 7% ductility.

关键词： aluminum zinc magnesium copper alloys non-isothermal cold rolling mechanical properties intermetallic compounds struc-ture defects

The detailed corrosion performance of bioresorbable Mg-0.8Ca alloy in physiological solutions

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Journal of Magnesium and Alloys 2022年第5期10卷 1326-1350页

作者： A.s.Gnedenkov s.L.sinebryukhov v.s.Filonina v.s.Egorkin A.Yu.Ustinov v.I.sergienko s.v.Gnedenkov Institute of Chemistry of FEB RAs 159 Pr.100-letiya VladivostokaVladivostok690022Russia

The electrochemical behaviour of biodegradable magnesium alloy Mg-0.8Ca was evaluated in a mammalian cell culture medium(MEM)and Na Cl solutions(0.9 wt.%, 0.3 wt.%) using traditional(EIs, PDP, OCP) and local scanning electrochemical(svET, sIET with p H-selective microelectrode) methods at the micro-and meso-level. Corrosion rates of samples in two different media were determined using weight loss tests. The influence of testing media components, alloy composition and microstructure on the material’s degradation process was *** svET/sIET test parameters were optimized for in vitro investigation of the bioresorbable material surface. The mechanism of the alloy’s bioresorption was suggested. The effect of microsized phases on the corrosion behaviour of the alloy was proved using complementary in situ monitoring and sKPFM measurements. The rapid degradation rate of the alloy is related to the presence of local microgalvanic cells formed by cathodic α-magnesium matrix and anodic Mg_(2)Ca phase. The highest corrosion activity was revealed in the first 12 min of sample exposure to MEM, followed by stabilization of corrosion process due to the material’s passivation. Using sEM-EDX analysis, micro-Raman spectroscopy and XPs analysis the composition of the corrosion products was determined. Degradation in MEM proceeds with a formation of magnesium-and-carbonate substituted hydroxyapatite-containing film on the sample’s surface. The low possibility of application of Mg-0.8Ca alloy without coating protection in implant surgery was highlighted.

关键词： Magnesium-calcium alloy Biodegradation Corrosion rate Electrochemistry Weight loss Minimum essential medium

Hydroxyapatite-containing PEO-coating design for biodegradable Mg-0.8Ca alloy: Formation and corrosion behaviour

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Journal of Magnesium and Alloys 2023年第12期11卷 4468-4484页

作者： A.s.Gnedenkov s.L.sinebryukhov v.s.Filonina s.v.Gnedenkov Institute of Chemistry of FEB RAs 159 Pr.100-letiya VladivostokaVladivostok690022Russian Federation

In this study, the biocompatible protective coating was formed using plasma electrolytic oxidation(PEO) on bioresorbable Mg-0.8Ca alloy. The composition of the formed coating was studied using XRD, sEM-EDX analysis, and micro-Raman spectroscopy. The uniform distribution of hydroxyapatite over the thickness of protective PEO-layer was established. Using traditional(EIs, PDP, OCP) and local scanning electrochemical methods(svET, sIET with H^(+)-selective microelectrode), the level of protective properties of PEO-layer in a biological environment(mammalian cell culture medium, MEM) was determined. It was established that modification of Mg-0.8Ca alloy surface by PEO contributes to a significant increase in the corrosion resistance of the surface layer, making it possible to control the process of material‘s biodegradation. The maximum local electrochemical activity was recorded after 72 h of testing, while for the uncoated sample,intense corrosion degradation was recorded in the first 12 min of exposure to the cell culture medium. Formation of the PEO-coating results in a twofold decrease in the corrosion current density(2.8·10^(-6)A cm^(-2)) and an increase in the impedance modulus measured at a low frequency(1.7·10^(4)Ω cm^(2)) in comparison with the uncoated material(9.5·10^(-6)A cm^(-2);8.1·10^(3)Ω cm^(2)). The mechanism of material bioresorption was established and a model for biodegradation process of Mg-0.8Ca alloy with hydroxyapatite-containing PEO-coating in MEM was proposed. Analysis of these results and comparing with others obtained by various scientific groups indicate the prospects for application of biocompatible PEO-coating on Mg-Ca alloy in implant surgery.

关键词： Magnesium-calcium alloy Biodegradation Implant surgery Plasma electrolytic oxidation Electrochemistry Minimum essential medium Hydroxyapatite

Modelling Magnetoresistance Effect in Limited Anisotropic semiconductors

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Chinese Physics Letters 2017年第7期34卷 212-214页

作者： Filippov v.v. Mitsuk s.v. Lipetsk state Pedagogical University of P. P. semenov-Tyan-shansky Lipetsk 398020 the Russian Federation Lipetsk state Technical University Lipetsk 398600 the Russian Federation

A macroscopic model of the magnetoresistance effect in fimited anisotropic semiconductors is built. This model allows us to solve the problem of measurement of physical magnetoresistance components of crystals and films. Based on a unified mathematical model the method is worked out enabling us to measure tensor components of the specific electrical resistance and the relative magnetoresistance of anisotropic semiconductors simultaneously.

关键词： Modelling Magnetoresistance Effect in Limited Anisotropic semiconductors

Generalised tanh-shaped hyperbolic potential: Klein–Gordon equation's bound state solution

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Communications in Theoretical Physics 2023年第7期75卷 22-32页

作者： v H Badalov s v Badalov Institute for Physical Problems Baku State University1148 BakuAzerbaijan Theoretical Materials Physics Paderborn UniversityD-33098 PaderbornGermany Theoretical PhysicsⅦ University of BayreuthD-95440 BayreuthGermany

The development of potential theory heightens the understanding of fundamental interactions in quantum *** this paper,the bound state solution of the modified radial Klein–Gordon equation is presented for generalised tanh-shaped hyperbolic potential from the Nikiforov–Uvarov *** resulting energy eigenvalues and corresponding radial wave functions are expressed in terms of the Jacobi polynomials for arbitrary l *** is also demonstrated that energy eigenvalues strongly correlate with potential parameters for quantum *** particular cases,the generalised tanh-shaped hyperbolic potential and its derived energy eigenvalues exhibit good agreement with the reported ***,the rovibrational energies are calculated for three representative diatomic molecules,namely H2,HCl and *** lowest excitation energies are in perfect agreement with experimental ***,the potential model is displayed to be a viable candidate for concurrently prescribing numerous quantum systems.

关键词： Klein-Gordon equation hyperbolic potential Nikiforov-Uvarov method diatomic molecules

Effect of nanoparticle(Pd, Pd/Pt, Ni) deposition on high temperature hydrogenation of Ti-v alloys in gaseous flow containing CO

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Progress in Natural science:Materials International 2017年第1期27卷 93-98页

作者： s.suwarno M.Williams J.K.solberg v.A.Yartys Department of Mechanical Engineering Institut Teknologi Sepuluh Nopember Department of Materials science and Engineering NTNU Institute for Energy Technology University of the Western Cape

The hydrogenation properties of Ti-v hydrides coated with nanoparticles have been studied in gaseous mixtures of argon and hydrogen with and without additions of 1% CO. Nanoparticles of Pd, Ni, and co-deposited Pd/Pt with particle sizes of;0–60 nm were formed by electroless deposition on the hydride surfaces. The alloy resistance to CO could be significantly improved by particle deposition. Large amounts of hydrogen were absorbed in a CO-containing gas when Ni and Pd/Pt deposition had been applied, while pure Pd deposition had no positive effect. Ni was found to have a stronger effect than those of Pd/Pt and Pd, possibly because of the size effect of Ni nanoparticles.

关键词： Metal hydride Titanium vanadium Nanoparticle Palladium Nickel Platinum Carbon monoxide

synthesis of MoO_3 by glow discharge in contact with water

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Plasma science and Technology 2019年第2期21卷 97-104页

作者： A v KHLYUsTOvA N A sIROTKIN A s KRAYEv v A TITOv A v AGAFONOv Laboratory of Chemistry of Carbohydrate Coordination Compounds and supermolecular system G.A.Krestov Institute of Solution Chemistry of RAS

An atmospheric pressure glow discharge was ignited between a molybdenum anode and the water surface of a cathode for the synthesis of MoO_3 powders. The action of glow discharge leads to the non-equilibrium evaporation of water, sputtering of the metal anode and formation of molybdenum(vI) oxide, which deposited on the anode. The chemical composition and morphology of the obtained powder were performed by using x-ray diffraction spectroscopy,scanning electron microscopy and Fourier transform infrared spectroscopy. It was found that the synthesized powders are pure α-MoO_3. The possible mechanism of the formation of molybdenum trioxide during glow discharge treatment was described. The photocatalytic performance of MoO_3 was estimated through the degradation of Rhodamine B under dark and Uv irradiation conditions. Orthorhombic MoO_3 exhibited the best photocatalytic activity for the photodegradation of Rhodamine B of 100% under Uv irradiation for 15 min.

关键词： molybdenum oxide glow discharge photocatalytic activity