scholarly journals Effect of chemical composition on the microstructure, hardness and electrical conductivity profiles of the Bi-Ge-In alloys

10.30544/561 ◽  
2020 ◽  
Vol 26 (4) ◽  
pp. 413-429
Author(s):  
Milena Premovic ◽  
Aleksandar Djordjevic ◽  
Dusko Minic ◽  
Milan Kolarevic ◽  
Milica Tomovic
Keyword(s):  
Mathematical Model ◽  
Electrical Conductivity ◽  
Composition Range ◽  
Brinell Hardness ◽  
Composition Analysis ◽  
Anova Analysis ◽  
Isothermal Sections ◽  
X Ray ◽  
Energy Dispersion Spectrometry ◽  
Phase Balance

In this study, the microstructure, hardness, and electrical properties of selected ternary Bi-Ge-In alloys were investigated. Isothermal sections of the Bi-Ge-In system at 25, 200, and 300 ° C were extrapolated using optimized thermodynamic parameters from the literature. The used experimental techniques include optical microscopy, X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectrometry (EDS), Brinell hardness, and electrical conductivity measurements. The results of EDS phase composition analysis were compared with the calculated isothermal sections and a good overall agreement was reached. The results of the XRD were also in line with the predicted phase balance. By using ANOVA analysis and experimental results of Brinell hardness and electrical conductivity, a mathematical model was suggested for the calculation of these properties along with all composition ranges. The appropriated mathematical model was subsequently used for the prediction of hardness and electrical conductivity throughout the whole composition range.

scholarly journals Effect of chemical composition on microstructure, hardness and electrical conductivity profiles of the Bi-Cu-Ga alloys at 100 °C

10.30544/211 ◽  
2016 ◽  
Vol 22 (3) ◽  
pp. 179-192
Author(s):  
Dejan Gurešić ◽  
Nadežda Talijan ◽  
Vladan Ćosović ◽  
Dušan Milisavljević ◽  
Aleksandar Đorđević ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Experimental Investigation ◽  
Isothermal Section ◽  
Brinell Hardness ◽  
Microstructural Analysis ◽  
Composition Analysis ◽  
Conductivity Measurements ◽  
Hardness Testing ◽  
X Ray Diffraction ◽  
X Ray

Theoretical calculation and experimental investigation of the isothermal section of a ternary Bi-Cu-Ga system at 100 oC are presented in this paper. Thermodynamic binary-based calculation of the isothermal section was performed using Pandat software. Experimental investigation included microstructural analysis carried out using light optical microscopy (LOM) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), phase composition analysis using X-ray diffraction (XRD), Brinell and Vickers hardness testing and electrical conductivity measurements. In total, thirty alloy samples with compositions along three vertical sections Bi-CuGa, Cu-BiGa and Ga-BiCu were studied. The obtained experimental results support the calculated phase regions of the isothermal section at 100 oC. Hardness of individual phases as well as hardness and electrical conductivity of the studied alloys were measured. Based on the experimentally obtained results iso-lines of Brinell hardness and electrical conductivity along the whole compositional range were calculated by using appropriate mathematical models.

scholarly journals Mechanical and electrical properties of ternary Ag-Bi-Ga system at 250 °C

10.30544/309 ◽  
2017 ◽  
Vol 23 (3) ◽  
pp. 227-240
Author(s):  
Duško Minić ◽  
Dragan Manasijević ◽  
Yong Du ◽  
Pavel Brož ◽  
Vladan Ćosović ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Energy Dispersive Spectrometry ◽  
Thermodynamic Assessment ◽  
Vickers Microhardness ◽  
Brinell Hardness ◽  
Hardness Test ◽  
X Ray ◽  
Mechanical And Electrical Properties ◽  
Comparative Review ◽  
The Individual

This paper presents a comparative review of the experimental and thermodynamic assessment of a ternary Ag-Bi-Ga system. An isothermal section at 250 °C was calculated using optimized thermodynamic data for the constitutive binaries. Microstructures and phase compositions of studied alloys were analyzed by scanning electron microscopy in combination with energy dispersive spectrometry and X-ray powder diffraction technique. The obtained experimental results were found to support the predicted phase equilibria rather well. The hardness of alloys from three vertical sections (Bi-AgGa, Ag-BiGa, and Ga-AgBi) was determined using Brinell hardness test while the hardness of the individual identified phases was determined using Vickers microhardness test. Additional electrical conductivity measurements were carried out on the same alloy samples. Based on the experimentally obtained results iso-lines of Brinell hardness and electrical conductivity for the entire compositional range were calculated.

Transport properties and the structure of vanadium phosphate glasses

1977 ◽  
Vol 55 (5) ◽  
pp. 436-441 ◽  
Author(s):  
B. D. Jordan ◽  
C. Calvo
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Composition Range ◽  
Phosphate Glasses ◽  
Vanadium Phosphate ◽  
Jump Frequency ◽  
X Ray ◽  
Concentration Variable ◽  
Hopping Model ◽  
Vanadium Ion

The adiabatic hopping model for the electrical conductivity of the vanadium phosphate glasses, V1+xP1−xO5−c/2, is examined in terms of their structures as derived from recent X-ray studies. These indicate that the relevant concentration variable for rationalizing the Seebeck coefficient data is c, the fraction of non-tetrahedral vanadium ion sites which are polarons. The polarons interlayer coordination number is 3. The average hopping distance varies by only 5% for 0 ≤ x ≤ 1. The experimental conductivities compared with[Formula: see text]suggest that n is near 3 and that the jump frequency v0 varies by nearly a factor of 3 over the composition range.

Phase Equilibria at 1173K in the Ni-Ti-Al System

1982 ◽  
Vol 19 ◽  
Author(s):  
W.W. Liang ◽  
P. Nash
Keyword(s):  
Experimental Data ◽  
Phase Equilibria ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Composition Range ◽  
Primary Crystallization ◽  
X Ray Diffraction ◽  
Isothermal Sections ◽  
X Ray

ABSTRACTIn a recent review of the published literature on this system it was concluded that there is a lack of experimental data in this system particularly in regions of the system with less than 75 atomic per cent of each one of the components (1). In order to provide some consistent data over a substantial range of composition an experimental determination of the phase equilibria at 1173K and from 0–50 atomic % Al is being carried out. The main experimental technique being used is quantitative electron microprobe analysis (JEOL 733) by wavelength dispersive x-ray spectrometry. In addition, x-ray diffraction is being used to establish the structures of phases present and optical metallography of cast structures to determine the fields of primary crystallization. In addition to establishing the phase equilibria at this temperature the composition range for the existence of the AlNi2Ti phase is being determined. The results thus far are compared with previous experimental data and calculated isothermal sections (2).

scholarly journals Mechanical and electrical properties of the Bi-Ge-Sn alloys

10.30544/562 ◽  
2020 ◽  
Vol 26 (4) ◽  
pp. 395-412
Author(s):  
Milena Premovic ◽  
Aleksandar Djordjevic ◽  
Dusko Minic ◽  
Milica Tomovic ◽  
Branko Radicevic ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Electrical Conductivity ◽  
Isothermal Section ◽  
Electrical Properties ◽  
Binary Systems ◽  
Brinell Hardness ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Mechanical And Electrical Properties ◽  
Good Agreement

Mechanical and electrical properties of the ternary Bi-Ge-Sn alloys were investigated in this study. Calculation of isothermal section at 200, 300, and 25 ºC was carried out by using optimized thermodynamic parameters for the constitutive binary systems. Microstructures of alloys were observed by using optical microscopy and scanning electron microscopy (SEM). Phases in microstructures have been detected by X-ray diffraction (XRD) analysis and compositions of the phase by energy dispersive spectrometry (EDS). EDS results were compared with the predicted isothermal section at 200 and 300 ºC, and good agreement has been reached between them. The Brinell hardness and electrical conductivity of selected alloys were measured.  Through ANOVA analysis and application of the obtained results, an appropriate mathematical model is proposed for every composition of alloys. By using the appropriated mathematical model for Brinell hardness and electrical conductivity, isolines for those properties were presented.

Removing Substrate Background in TEM Microanalysis

1974 ◽  
Vol 32 ◽  
pp. 568-569
Author(s):  
John C. Russ ◽  
Nicholas C. Barbi
Keyword(s):  
Electrical Conductivity ◽  
Rapid Growth ◽  
Organic Film ◽  
Absolute Concentration ◽  
Background Signal ◽  
X Ray ◽  
Elemental Concentrations ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
The Continuum

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.

BETTER UNDERSTANDING THE GEOLOGY OF CENTRAL CUBA THROUGH STREAM SEDIMENT COMPOSITION ANALYSIS USING X-RAY DIFFRACTION

2019 ◽  
Author(s):  
Landon Williamson ◽  
◽  
Nicolas Perdrial ◽  
John M. Hughes ◽  
Mae Kate Campbell ◽  
...  
Keyword(s):  
Stream Sediment ◽  
Composition Analysis ◽  
X Ray Diffraction ◽  
Sediment Composition ◽  
X Ray

Electrical conductivity studies on silica phases and the effects of phase transformation

2019 ◽  
Vol 104 (12) ◽  
pp. 1800-1805
Author(s):  
George M. Amulele ◽  
Anthony W. Lanati ◽  
Simon M. Clark
Keyword(s):  
Electrical Conductivity ◽  
Activation Volume ◽  
Activation Enthalpy ◽  
Hydrogen Charge ◽  
Charge Compensation ◽  
Composition Analysis ◽  
Conductivity Measurements ◽  
Pressure System ◽  
Electrical Conductivities ◽  
Silica Phases

Abstract Starting with the same sample, the electrical conductivities of quartz and coesite have been measured at pressures of 1, 6, and 8.7 GPa, respectively, over a temperature range of 373–1273 K in a multi-anvil high-pressure system. Results indicate that the electrical conductivity in quartz increases with pressure as well as when the phase change from quartz to coesite occurs, while the activation enthalpy decreases with increasing pressure. Activation enthalpies of 0.89, 0.56, and 0.46 eV, were determined at 1, 6, and 8.7 GPa, respectively, giving an activation volume of –0.052 ± 0.006 cm3/mol. FTIR and composition analysis indicate that the electrical conductivities in silica polymorphs is controlled by substitution of silicon by aluminum with hydrogen charge compensation. Comparing with electrical conductivity measurements in stishovite, reported by Yoshino et al. (2014), our results fall within the aluminum and water content extremes measured in stishovite at 12 GPa. The resulting electrical conductivity model is mapped over the magnetotelluric profile obtained through the tectonically stable Northern Australian Craton. Given their relative abundances, these results imply potentially high electrical conductivities in the crust and mantle from contributions of silica polymorphs. The main results of this paper are as follows:The electrical conductivity of silica polymorphs is determined by impedance spectroscopy up to 8.7 GPa.The activation enthalpy decreases with increasing pressure indicating a negative activation volume across the silica polymorphs.The electrical conductivity results are consistent with measurements observed in stishovite at 12 GPa.

scholarly journals Thermoelectric Generator Using Polyaniline-Coated Sb2Se3/β-Cu2Se Flexible Thermoelectric Films

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1518
Author(s):  
Minsu Kim ◽  
Dabin Park ◽  
Jooheon Kim
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Field Emission ◽  
Photoelectron Spectroscopy ◽  
Thermoelectric Generator ◽  
Hydrothermal Reaction ◽  
Water Evaporation ◽  
Pani Film ◽  
Portable Devices ◽  
X Ray

Herein, Sb2Se3 and β-Cu2Se nanowires are synthesized via hydrothermal reaction and water evaporation-induced self-assembly methods, respectively. The successful syntheses and morphologies of the Sb2Se3 and β-Cu2Se nanowires are confirmed via X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), and field emission transmission electron microscopy (FE-TEM). Sb2Se3 materials have low electrical conductivity which limits application to the thermoelectric generator. To improve the electrical conductivity of the Sb2Se3 and β-Cu2Se nanowires, polyaniline (PANI) is coated onto the surface and confirmed via Fourier-transform infrared spectroscopy (FT-IR), FE-TEM, and XPS analysis. After coating PANI, the electrical conductivities of Sb2Se3/β-Cu2Se/PANI composites were increased. The thermoelectric performance of the flexible Sb2Se3/β-Cu2Se/PANI films is then measured, and the 70%-Sb2Se3/30%-β-Cu2Se/PANI film is shown to provide the highest power factor of 181.61 μW/m·K2 at 473 K. In addition, a thermoelectric generator consisting of five legs of the 70%-Sb2Se3/30%-β-Cu2Se/PANI film is constructed and shown to provide an open-circuit voltage of 7.9 mV and an output power of 80.1 nW at ΔT = 30 K. This study demonstrates that the combination of inorganic thermoelectric materials and flexible polymers can generate power in wearable or portable devices.

Preliminary Study of Alginates Extracted from Brown Algae (Sargassum sp.) Available in Madura Island as Composite Based Hydrogel Materials

2019 ◽  
Vol 964 ◽  
pp. 240-245 ◽  
Author(s):  
Amaliya Rasyida ◽  
Thalyta Rizkha Pradipta ◽  
Sigit Tri Wicaksono ◽  
Vania Mitha Pratiwi ◽  
Yeny Widya Rakhmawati
Keyword(s):  
Sodium Alginate ◽  
Brown Algae ◽  
Extraction Process ◽  
Composition Analysis ◽  
3D Printer ◽  
X Ray Diffraction ◽  
X Ray ◽  
3D Printed ◽  
Preliminary Study

Utilization of brown algae especially in Madura, where it’s close to Surabaya, only limited for food. This become a reference for developing and increasing the potential of this algae by extracting one of the ingredients, namely alginate. This paper deals with the characterization of sodium alginate extracted from sargassum sp. using modified-purified calcium routes. The extracted sodium alginate will be further used as composite hydrogel materials and compared with commercial sodium alginate. Hereafter, the synthesized composite is expected to be bio-ink for 3d printer. Chemical composition analysis were analyzed using X-Ray Fluorosense (XRF) followed by Fourier-transform infrared spectroscopy (FTIR) analysis to identify the functional group of composite and X-Ray Diffraction (XRD). Furthermore, viscosity bath is performed to compare the viscosity of extracted and commercial one. The result shows that modified-purified calcium routes in the extraction process of sodium alginate is desirable for improving their properties. Interestingly enough, with the goal of using it as bio-ink in 3d printed fabrication, the synthesized composite shows viscosity, 300 cSt, which meets the criteria for bio-ink in 3d printer.

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