scholarly journals Composition and

2018 ◽  
Vol 20 (2) ◽  
pp. 145 ◽  
Author(s):  
M. Ved’ ◽  
N. Sakhnenko ◽  
I. Yermolenko ◽  
G. Yar-Mukhamedova ◽  
R. Atchibayev
Keyword(s):  
Current Density ◽  
Ternary Alloys ◽  
Electrode Impedance ◽  
Refractory Component ◽  
X Ray ◽  
Electrode Impedance Spectroscopy ◽  
Competitive Reduction ◽  
Off Time ◽  
Polarization Resistance Method ◽  
Amorphous Part

Principles of three component Iron-Cobalt-Tungsten alloys electrodeposition from complex Fe (III) based citrate electrolytes are discussed. It is shown, that deposition of ternary alloys proceeds through competitive reduction of cobalt and tungsten with iron. With increasing ligand concentration coatings are enriched with a refractory component; however, increasing current density favors a reverse trend. The effect of both current density and pulse on/off time on the quality, content of alloying metals and surface topography of electrolytic coatings were determined. The application of pulsed electrolysis provides increasing tungsten content up to 13 at.%, at current efficiency of 70–75%. Globular relief of Fe-Co-W coatings is caused by refractory metals incorporation, and crystalline and amorphous parts of structure are visualized by X-ray spectroscopy, including inter-metallic phases Co7W6, Fe7W6 along with α-Fe and Fe3C. The crystallite size of the amorphous part is near 7–8 nm. Corrosion resistance of the coatings is 1.3–2.0 orders of magnitude higher than the substrate parameters as follows from data of polarization resistance method and electrode impedance spectroscopy.

scholarly journals Effect of Electrodeposition Parameters on the Composition and Surface Topography of Nanostructured Coatings by Tungsten with Iron and Cobalt

2020 ◽  
Vol 22 (1) ◽  
pp. 19
Author(s):  
G. Yar-Mukhamedova ◽  
M. Ved’ ◽  
I. Yermolenko ◽  
N. Sakhnenko ◽  
A. Karakurkchi ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Current Density ◽  
Steel Substrate ◽  
Structural Features ◽  
Refractory Component ◽  
Reduction Of Iron ◽  
Citrate Electrolyte ◽  
Spherical Agglomerates ◽  
Competitive Reduction ◽  
Off Time

The electrodeposition of binary and ternary coatings Fe-W and Fe-Co-W from mono ligand citrate electrolyte has been investigated. The Fe-Co-W coatings were formed from electrolytes, which composition differs in the ratio of the concentrations of the alloying components and the ligand content. The investigation results indicate a competitive reduction of iron, cobalt and tungsten, the nature of which depends both on the ratio of electrolyte components, and electrolysis parameters. The effect of both current density amplitude and pulse on off time on quality, composition and surface morphology of the galvanic alloys was determined. Coatings deposited on a direct current with a density of more than 6.5 A/dm2, crack and peel off from the substrate due to the inclusion of Fe (III) compounds containing hydroxide anions. The use of non-stationary electrolysis allows us to extend the working range of current density to 8.0 A/dm2 and form electrolytic coatings of sufficient quality with significant current efficiency and the content of the refractory component. The presence of the Co7W6, Fe7W6, α-Fe, and Fe3C phases detected in the Fe-Co-W deposits reflects the competition between the alloying metals reducing from hetero-nuclear complexes. The surface of binary and ternary coatings is characterized by the presence of spherical agglomerates and is more developed in comparison with steel substrate. The parameters Ra and Rq for electrolytic alloy Fe-W are of 0.1, for Fe-Co-W are 0.3, which exceeds the performance of a polished steel substrate (Ra = 0.007 and Rq = 0.010). These properties prospect such alloys as a multifunctional layer are associated with structural features, surface morphology, and phase composition.

Elemental mass loss in silicate minerals during x-ray analysis

1990 ◽  
Vol 48 (4) ◽  
pp. 804-805
Author(s):  
P.E. Champness ◽  
R.W. Devenish
Keyword(s):  
Mass Loss ◽  
Current Density ◽  
Damage Mechanism ◽  
Beam Current ◽  
Single Chain ◽  
Plagioclase Feldspar ◽  
X Ray ◽  
Alkali Ions ◽  
Structural Order ◽  
Sheet Silicate

It has long been recognised that silicates can suffer extensive beam damage in electron-beam instruments. The predominant damage mechanism is radiolysis. For instance, damage in quartz, SiO2, results in loss of structural order without mass loss whereas feldspars (framework silicates containing Ca, Na, K) suffer loss of structural order with accompanying mass loss. In the latter case, the alkali ions, particularly Na, are found to migrate away from the area of the beam. The aim of the present study was to investigate the loss of various elements from the common silicate structures during electron irradiation at 100 kV over a range of current densities of 104 - 109 A m−2. (The current density is defined in terms of 50% of total current in the FWHM probe). The silicates so far ivestigated are:- olivine [(Mg, Fe)SiO4], a structure that has isolated Si-O tetrahedra, garnet [(Mg, Ca, Fe)3Al2Si3AO12 another silicate with isolated tetrahedra, pyroxene [-Ca(Mg, Fe)Si2O6 a single-chain silicate; mica [margarite, -Ca2Al4Si4Al4O2O(OH)4], a sheet silicate, and plagioclase feldspar [-NaCaAl3Si5O16]. Ion- thinned samples of each mineral were examined in a VG Microscopes UHV HB501 field- emission STEM. The beam current used was typically - 0.5 nA and the current density was varied by defocussing the electron probe. Energy-dispersive X-ray spectra were collected every 10 seconds for a total of 200 seconds using a Link Systems windowless detector. The thickness of the samples in the area of analysis was normally 50-150 nm.

Mechanically Driven Dissolution of Sn in Near-Equiatomic Bcc FeCo

2012 ◽  
Vol 194 ◽  
pp. 187-193 ◽  
Author(s):  
J.M. Loureiro ◽  
Benilde F.O. Costa ◽  
Gerard Le Caër ◽  
Bernard Malaman
Keyword(s):  
Magnetic Field ◽  
Solid Solutions ◽  
Room Temperature ◽  
Hyperfine Magnetic Field ◽  
Ternary Alloys ◽  
119Sn Mössbauer Spectroscopy ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Powder Mixtures ◽  
X Ray

Ternary alloys, (Fe50−x/2Co50−x/2)Snx(x ≤ 33 at.%), are prepared by mechanical alloying from powder mixtures of the three elements. As-milled alloys are studied by X-ray diffraction and 57Fe and 119Sn Mössbauer spectroscopy. The solubility of Sn in near-equiatomic bcc FeCo is increased from ~0.5 at. % at equilibrium to ~20 at.% in the used milling conditions. The average 119Sn hyperfine magnetic field at room temperature is larger, for any x, than the corresponding fields in mechanically alloyed Fe-Sn solid solutions.

Morphology and Crystallographic Characterization of Nickel Nanowires—Influence of Magnetic Field and Current Density During Synthesis

2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Mahendran Samykano ◽  
Ram Mohan ◽  
Shyam Aravamudhan
Keyword(s):  
Magnetic Field ◽  
Current Density ◽  
Quality Data ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nickel Nanowires ◽  
Helium Ion ◽  
Sem Imaging

This paper presents results and discussion from a comprehensive morphological and crystallographic characterization of nickel nanowires synthesized by template-based electrodeposition method. In particular, the influence of magnetic and electric field (current density) conditions during the synthesis of nickel nanowires was studied. The structure and morphology of the synthesized nanowires were studied using Helium ion microscopy (HIM) and scanning electron microscopy (SEM) methods. The HIM provided higher quality data and resolution compared to conventional SEM imaging. The crystallographic properties of the grown nanowires were also studied using X-ray diffraction (XRD). The results clearly indicated that the morphological and crystallographic properties of synthesized nickel nanowires were strongly influenced by the applied magnetic field and current density intensity during the synthesis process.

Structural Properties of Ni-Co Electroplated Coatings Studied by X-Ray Micro-Beam

2014 ◽  
Vol 635 ◽  
pp. 204-207 ◽  
Author(s):  
Ondrej Milkovič ◽  
Mária Hagarová ◽  
Jana Michaliková ◽  
Matúš Horváth
Keyword(s):  
Synchrotron Radiation ◽  
Structural Properties ◽  
Current Density ◽  
Deposition Process ◽  
Transmission Mode ◽  
Structure Parameters ◽  
Electrodeposition Process ◽  
Cu Substrate ◽  
X Ray ◽  
Current Densities

In this article we focused to influence of current density on the structure parameters evaluated by microdiffraction experiment in transmission mode using synchrotron radiation. For this purpose the coatings of Ni-Co alloy were deposited on the Cu substrate using different current densities during the electrodeposition process. The results of the microdiffraction experiment showed the structure uniformity of the coatings along their thickness, as well as changes in the structure parameters depending on the used current density during the deposition process.

scholarly journals Mn-Induced Thermal Stability of L10 Phase in Fept Magnetic Nanoscale Ribbons

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1278
Author(s):  
Alina Daniela Crisan ◽  
Aurel Leca ◽  
Dan Pantelica ◽  
Ioan Dan ◽  
Ovidiu Crisan
Keyword(s):  
Rare Earth ◽  
Single Phase ◽  
Permanent Magnets ◽  
Magnetic Hysteresis ◽  
Ternary Alloys ◽  
Large Temperature ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Operation Conditions

Magnetic nanoscale materials exhibiting the L10 tetragonal phase such as FePt or ternary alloys derived from FePt show most promising magnetic properties as a novel class of rare earth free permanent magnets with high operating temperature. A granular alloy derived from binary FePt with low Pt content and the addition of Mn with the nominal composition Fe57Mn8Pt35 has been synthesized in the shape of melt-spun ribbons and subsequently annealed at 600 °C and 700 °C for promoting the formation of single phase, L10 tetragonal, hard magnetic phase. Proton-induced X-ray emission spectroscopy PIXE has been utilized for checking the compositional effect of Mn addition. Structural properties were analyzed using X-ray diffraction and diffractograms were analyzed using full profile Rietveld-type analysis with MAUD (Materials Analysis Using Diffraction) software. By using temperature-dependent synchrotron X-ray diffraction, the disorder–order phase transformation and the stability of the hard magnetic L10 phase were monitored over a large temperature range (50–800 °C). A large interval of structural stability of the L10 phase was observed and this stability was interpreted in terms of higher ordering of the L10 phase promoted by the Mn addition. It was moreover found that both crystal growth and unit cell expansion are inhibited, up to the highest temperature investigated (800 °C), proving thus that the Mn addition stabilizes the formed L10 structure further. Magnetic hysteresis loops confirmed structural data, revealing a strong coercive field for a sample wherein single phase, hard, magnetic tetragonal L10 exists. These findings open good perspectives for use as nanocomposite, rare earth free magnets, working in extreme operation conditions.

scholarly journals Microstructure and Electrical Properties of Low-Voltage Barium Titanate Doped Zinc Oxide Varistor Ceramics

2019 ◽  
Vol 8 (4) ◽  
pp. 2713-2718
Keyword(s):  
Zinc Oxide ◽  
Electrical Properties ◽  
Barium Titanate ◽  
Grain Boundary ◽  
Barrier Height ◽  
Current Density ◽  
Low Voltage ◽  
X Ray ◽  
Highly Nonlinear ◽  
Zno Varistors

In the present, varistor ceramics through the combination of zinc oxide (ZnO) with a perovskite material have become widespread because of their unique properties for a wide range of applications in electronic protection devices. Low-voltage zinc oxide (ZnO) varistors with fast response and highly nonlinear electrical properties for overvoltage protection in an integrated circuit are increasingly significant in the application of low-voltage electronics. The present study highlights the interaction between barium titanate (BaTiO3 ) and ZnO varistors through the employment of solid-state reaction method in the production of low-voltage varistors. The effects of BaTiO3 on the microstructure of ZnO varistors were analyzed through scanning electron microscopy (SEM), energy dispersive X-ray analysis spectroscopy (EDS) and X-ray diffraction (XRD). The EDS analysis and XRD measurements suggest the presence of ZnO and BaTiO3 phases. The electrical properties of BaTiO3 -doped ZnO varistors were examined based on the current density-electric field (J-E) characteristics measurement. The varistor properties showed the nonlinear coefficient (α) from 1.8 to 4.8 with the barrier height (φB) ranged from 0.70 to 0.88 eV. The used of BaTiO3 additive in ZnO varistors produced varistor voltages of 4.7 to 14.1 V/mm with the voltage per grain boundary (Vgb) was measured in the ranges 0.03 to 0.05 V. The lowest leakage current density was 348 µA/cm2 , obtained at the samples containing 12 wt.% BaTiO3 with high barrier height. The reduction in barrier height with increasing BaTiO3 content was associated with the excessive amount of BaTiO3 phase, hence cause the deterioration of active grain boundary due to the variation of oxygen (O) vacancies in the grain boundary.

Phase Equilibria and Solidification of Al-Rich Ai-Ui-Cu Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
Sinn-Wen Chen ◽  
Y. Austin Chang
Keyword(s):  
Liquidus Projection ◽  
Thermodynamic Description ◽  
Type Equation ◽  
Ternary Alloys ◽  
X Ray Diffraction ◽  
Thermodynamic Models ◽  
Isothermal Sections ◽  
X Ray ◽  
Cu Alloys ◽  
Calculated Amount

AbstractA liquidus projection of the Al-rich Al-Li-Cu system is proposed. The proposed liquidus projection was based on DTA, X-ray diffraction, metallography, EPMA, SEM, and chemical analysis of 50 ternary alloys. Using these data and those reported in the literature, and thermodynamic models of Al-Li, AI-Cu and Cu-Li, a thermodynamic description of the Al-rich AI-Li-Cu system was developed. The calculated isothermal sections at several temperatures and the liquidus projection are in agreement with the experimental determinations. Combining the thermodynamic models and a Scheil-type equation, quantitative solidification paths were described. The calculated amount of primary solidification phase was compared to the experimental determination.

Effect of ZnO Nano-Oxide Addition on the Superconducting Properties of the (Bi.Pb)2223 Phase

2011 ◽  
Vol 324 ◽  
pp. 241-244 ◽  
Author(s):  
R. Mawassi ◽  
R. Awad ◽  
Mohamad Roumie ◽  
M. Kork ◽  
I. Hassan
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Flux Pinning ◽  
High Temperature Superconductors ◽  
Weak Links ◽  
Superconducting Properties ◽  
X Ray ◽  
Weight Percentage ◽  
Nano Oxide

The major limitation of Bi-system superconductor applications is the intergrain weak links and weak flux pinning capability producing low critical current density of the Bibased phases. In order to enhance these characteristics and other superconducting properties, effective flux pinning centers are introduced into high temperature superconductors. In this work, different weight percentages of ZnO nano oxide were introduced at the final stage of the Bi1.8Pb0.4Sr2Ca2Cu3O10-y superconductor preparation process. Phase characterization was completed by X-ray diffraction (XRD). Exact constitution of the samples was determined using particle induced X-ray emission (PIXE). Granular and microstructure were investigated using scanning electron microscopy (SEM). Electrical resistivity as function of the temperature was carried to evaluate the relative performance of samples, and finally, E-J characteristic curves were obtained at 77K. Using 0.4 ZnO weight percentage, the electrical and granular properties were greatly enhanced, indicating more efficient pinning mechanisms. A critical current density of 949 A/cm2 was obtained which represents more than twice the value obtained for the pure sample (Jc= 445 A/cm2).

Mössbauer spectroscopy and X-ray diffraction study of the Fe3−xT x Al ternary alloys

ICAME 2005 ◽  
2006 ◽  
pp. 979-979
Author(s):  
Krzysztof Brząkalik ◽  
Janusz E. Brząkckowiak
Keyword(s):  
Mössbauer Spectroscopy ◽  
Diffraction Study ◽  
Mossbauer Spectroscopy ◽  
Ternary Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mößbauer Spectroscopy
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