scholarly journals Structural and Electrical Studies of Bi2Se3 Nanomaterials by Solvothermal Method for Thermo-electric Applications

2021 ◽  
Author(s):  
Asvini V ◽  
Subbulekshmi S ◽  
Saravanan G ◽  
Ravichandran K
Keyword(s):  
Impedance Spectroscopy ◽  
Room Temperature ◽  
Solvothermal Method ◽  
Morphological Characterization ◽  
Annealed Sample ◽  
Metallic State ◽  
Thermo Electric ◽  
Electrical Studies ◽  
Redox Peak ◽  
Average Grain Size

Abstract The Bi2Se3 nanoparticles were synthesized by the solvothermal method. The structural and morphological characterization has been done using XRD, HRSEM and Raman while electrical studies at room temperature were analyzed using impedance spectroscopy and cyclic voltmetry. The phase formation was confirmed through XRD measurement and average grain size was found to be 25 nm for as-prepared sample and 37 nm for 650 ºC for 12 hours annealed sample. Raman spectrum appears in the higher frequency range, this is due to stronger bonding forces, i.e the peak at 524 cm− 1 or may arise due to the overtones of A11g and E2g modes. The redox behavior was due to Bi3+ converted into Bi2+ and Bi metallic state. This redox peak was confined the formation of Bi2Se3 nanoparticles. The high temperature electrical conductivity studies were performed as-prepared and annealed sample using impedance spectroscopy.

scholarly journals Experimental and Numerical Investigation of the ECAP Processed Copper: Microstructural Evolution, Crystallographic Texture and Hardness Homogeneity

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 607
Author(s):  
A. I. Alateyah ◽  
Mohamed M. Z. Ahmed ◽  
Yasser Zedan ◽  
H. Abd El-Hafez ◽  
Majed O. Alawad ◽  
...  
Keyword(s):  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Cross Section ◽  
Room Temperature ◽  
Pure Copper ◽  
High Density ◽  
Ecap Processing ◽  
Heterogeneous Distribution ◽  
Angular Pressing ◽  
Average Grain Size

The current study presents a detailed investigation for the equal channel angular pressing of pure copper through two regimes. The first was equal channel angular pressing (ECAP) processing at room temperature and the second was ECAP processing at 200 °C for up to 4-passes of route Bc. The grain structure and texture was investigated using electron back scattering diffraction (EBSD) across the whole sample cross-section and also the hardness and the tensile properties. The microstructure obtained after 1-pass at room temperature revealed finer equiaxed grains of about 3.89 µm down to submicrons with a high density of twin compared to the starting material. Additionally, a notable increase in the low angle grain boundaries (LAGBs) density was observed. This microstructure was found to be homogenous through the sample cross section. Further straining up to 2-passes showed a significant reduction of the average grain size to 2.97 µm with observable heterogeneous distribution of grains size. On the other hand, increasing the strain up to 4-passes enhanced the homogeneity of grain size distribution. The texture after 4-passes resembled the simple shear texture with about 7 times random. Conducting the ECAP processing at 200 °C resulted in a severely deformed microstructure with the highest fraction of submicron grains and high density of substructures was also observed. ECAP processing through 4-passes at room temperature experienced a significant increase in both hardness and tensile strength up to 180% and 124%, respectively.

GRAIN REFINEMENT AND MICROSTRUCTURE EVOLUTION IN ALUMINUM A2618 ALLOY BY HIGH-PRESSURE TORSION

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Intan Fadhlina Mohamed ◽  
Seungwon Lee ◽  
Kaveh Edalati ◽  
Zenji Horita ◽  
Shahrum Abdullah ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Grain Refinement ◽  
Room Temperature ◽  
Rotation Speed ◽  
High Pressure Torsion ◽  
Applied Pressure ◽  
Saturation Level ◽  
Microstructural Refinement ◽  
Average Grain Size

This work presents a study related to the grain refinement of an aluminum A2618 alloy achieved by High-Pressure Torsion (HPT) known as a process of Severe Plastic Deformation (SPD). The HPT is conducted on disks of the alloy under an applied pressure of 6 GPa for 1 and 5 turns with a rotation speed of 1 rpm at room temperature. The HPT processing leads to microstructural refinement with an average grain size of ~250 nm at a saturation level after 5 turns. Gradual increases in hardness are observed from the beginning of straining up to a saturation level. This study thus suggests that hardening due to grain refinement is attained by the HPT processing of the A2618 alloy at room temperature.

ATOMIC FORCE MICROSCOPY AND XRD ANALYSIS OF SILVER FILMS DEPOSITED BY THERMAL EVAPORATION

2006 ◽  
Vol 20 (02) ◽  
pp. 217-231 ◽  
Author(s):  
MUHAMMAD MAQBOOL ◽  
TAHIRZEB KHAN
Keyword(s):  
Atomic Force Microscopy ◽  
Grain Size ◽  
Surface Characterization ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Xrd Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Average Grain Size ◽  
20 Nm

Thin films of pure silver were deposited on glass substrate by thermal evaporation process at room temperature. Surface characterization of the films was performed using X-ray diffraction (XRD) and atomic force microscopy (AFM). Thickness of the films varied between 20 nm and 72.8 nm. XRD analysis provided a sharp peak at 38.75° from silver. These results indicated that the films deposited on glass substrates at room temperature are crystalline. Three-dimension and top view pictures of the films were obtained by AFM to study the grain size and its dependency on various factors. Average grain size increased with the thickness of the deposited films. A minimum grain size of 8 nm was obtained for 20 nm thick films, reaching 41.9 nm when the film size reaches 60 nm. Grain size was calculated from the information provided by the XRD spectrum and averaging method. We could not find any sequential variation in the grain size with the growth rate.

Room temperature thermo-electric pumping in mid-infrared light-emitting diodes

2013 ◽  
Vol 103 (18) ◽  
pp. 183513 ◽  
Author(s):  
Parthiban Santhanam ◽  
Duanni Huang ◽  
Rajeev J. Ram ◽  
Maxim A. Remennyi ◽  
Boris A. Matveev
Keyword(s):  
Room Temperature ◽  
Light Emitting Diodes ◽  
Infrared Light ◽  
Thermo Electric ◽  
Mid Infrared ◽  
Light Emitting

scholarly journals The effects of additive on microstructure and electrical properties of batio3 ceramics

2004 ◽  
Vol 1 (3) ◽  
pp. 89-98 ◽  
Author(s):  
Vesna Paunovic ◽  
Ljiljana Zivkovic ◽  
Ljubomir Vracar ◽  
Vojislav Mitic ◽  
Miroslav Miljkovic
Keyword(s):  
Dielectric Constant ◽  
Curie Temperature ◽  
Room Temperature ◽  
Low Frequency ◽  
Dissipation Factor ◽  
The Other ◽  
Uniform Microstructure ◽  
Average Grain Size ◽  
Solid State Sintering ◽  
Curie Temperatures

In this paper comparative investigations of microstructure and dielectric properties of BaTiO3 ceramics doped with 1.0 wt% of Nb2O5, MnCO3 and CaZrO3 have been done. BaTiO3 samples were prepared using conventional method of solid state sintering at 13000C for two hours. Two distinguish micro structural regions can be observed in sample doped with Nb2O5. The first one, with a very small grained microstructure and the other one, with a rod like grains. In MnCO3 and CaZrO3 doped ceramics the uniform microstructure is formed with average grain size about 0.5- 2?m and 3-5?m respectively. The highest value of dielectric permittivity at room temperature and the greatest change of permittivity in function of temperature were observed in MnCO3/BaTiO3. In all investigated samples dielectric constant after initially large value at low frequency attains a constant value at f = 6kHz. A dissipation factor is independent of frequency greater than 10 kHz and, depending of systems, lies in the range from 0.035 to 0.25. At temperatures above Curie temperatures, the permittivity of all investigated samples follows a Curie- Weiss law. A slight shift of Curie temperature to the lower temperatures, in respect of Curie temperature for undoped BaTiO3, was observed in all investigated samples.

scholarly journals In Situ Hvem Study of Ion Irradiation-Induced Grain Growth in Au Thin Films

1988 ◽  
Vol 128 ◽  
Author(s):  
Joyce C. Liu ◽  
Jian Li ◽  
J. W. Mayer ◽  
Charles W. Allen ◽  
Lynn E. Rehn
Keyword(s):  
Grain Growth ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Average Grain Size ◽  
In Situ Observations ◽  
Au Thin Films ◽  
Grain Coalescence

ABSTRACTIn situ observations of 1.5 MeV Xe+ ion irradiated Au films at room temperature and at 150°C reveal the evolution of grain growth: the average grain size increases by the mechanisms of grain boundary migration and grain coalescence.

Pretreated Lignocellulosic Waste Mediated Biosynthesis of Silver Nanoparticles Under Room Temperature

2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660001 ◽  
Author(s):  
V. P. Manjamadha ◽  
Karuppan Muthukumar
Keyword(s):  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Room Temperature ◽  
Nitrate Solution ◽  
Silver Ions ◽  
Silver Nitrate Solution ◽  
Morphological Characterization ◽  
Alternative Source ◽  
X Ray ◽  
Antibacterial Performance

The current work elucidates the utilization of biowaste as a valuable reducing agent for the synthesis of silver nanoparticles. In this study, the wastewater generated during the alkaline pretreatment of lignocellulosic wastes (APLW) was used as a bioreductant to reduce silver nitrate under room temperature. Synthesis of stable silver nanoparticles (AgNPs) was achieved rapidly on addition of APLW into the silver nitrate solution (1[Formula: see text]mM). The morphological characterization of AgNPs was performed using field emission scanning electron microscopy (FESEM). The micrograph clearly depicted the presence of spherical AgNPs. The presence of elemental silver along with biomoilties was determined using energy dispersive X-ray spectroscopy (EDAX) analysis. The X-ray diffraction (XRD) study proved the crystalline form of stable AgNPs. The AgNPs exhibited excellent antibacterial performance against Gram negative organism. The immediate bioreduction of silver ions using APLW was well illustrated in the present study. Thus, APLW serve as an alternative source for reducing agents instead of utilizing valuable medicinal plants for nanoparticles synthesis.

Fabrication and Morphological Characterization of Barium Titanate-Based Polymeric Nanocomposite Thin Films

2018 ◽  
pp. 50-59 ◽  
Author(s):  
Sudhanshu Singh ◽  
Umesh Kumar Dwivedi
Keyword(s):  
Barium Titanate ◽  
Room Temperature ◽  
Composite Films ◽  
Morphological Characterization ◽  
Solution Casting ◽  
Weight Percentage ◽  
Casting Technique ◽  
Nanocomposite Thin Films ◽  
Solution Casting Technique

In this critical review chapter, the authors explain the development of composite films of Barium Titanate (BaTiO3) and Poly (methyl methacrylate) prepared by solution casting technique. Different weight percentage composition of BaTiO3 has been selected to find out the best optimization condition for further investigation and correlate the results. The structural properties have been carried out at room temperature using XRD. Efforts have been made to correlate the results with investigated XRD results of pure BaTiO3 and its composites as observed by other workers at room temperature. The flow of experimental work and microscopic images are explained.

Low-Temperature Magnetic Hysteresis in Nd(Pr)-Fe-B Nanostructured Alloys with Nd2Fe14B Type Main Phase Composition

2018 ◽  
Vol 386 ◽  
pp. 125-130 ◽  
Author(s):  
Dmitriy Sergeevich Neznakhin ◽  
Galina Aleksandrovna Politova ◽  
Lev Aleksandrovich Ivanov ◽  
Aleksey Sergeevich Volegov ◽  
Denis Ivanovich Gorbunov ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Energy ◽  
Magnetic Phase ◽  
Magnetic Hysteresis ◽  
Nanostructured Alloys ◽  
Grain Sizes ◽  
Energy Product ◽  
Magnetization Saturation ◽  
Average Grain Size ◽  
Hysteresis Properties

Magnetic hysteresis properties of nanostructured industrially manufactured Nd-Fe-B and Pr-Fe-B alloys on the base of a tetragonal Nd2Fe14B (2-14-1) hard magnetic phase (MQP-B, MQP-B+ and MQP-16-7 brands) have been investigated at 4.2 K in magnetic fields up to 58 T. The chemical composition of the alloys given in the certificates was defined more precisely. The grain sizes of the main 2-14-1 phase were determined. The average grain size is much smaller than a critical single domain diameter. Coercivity, remanence magnetization, saturation magnetization and maximal magnetic energy product were determined at 4.2 K and compared with those obtained at room temperature.

Structural and Thermal Properties of YMn1-xRuxO3

2014 ◽  
Vol 975 ◽  
pp. 69-72 ◽  
Author(s):  
Rajesh K. Thakur ◽  
Rasna Thakur ◽  
N. Kaurav ◽  
G.S. Okram ◽  
N.K. Gaur
Keyword(s):  
Ionic Radius ◽  
Room Temperature ◽  
Conduction Mechanism ◽  
Single Phase ◽  
Lattice Parameters ◽  
Power Measurement ◽  
Electric Transport ◽  
Thermo Electric ◽  
Xrd Study ◽  
Single Phase Formation

We report the structural and thermo-power measurement of the ruthenium doped YMnO3 compounds. The room temperature XRD study shows the single phase formation of the reported compounds with the incremental unit cell volume and lattice parameters attributed to the larger ionic radius of the Ru3+ (0.68 Å) and Ru4+ (0.62 Å) as compared with that of the Mn3+ (0.65 Å) Mn4+ (0.52 Å). The observed variation of lattice parameters provides us valuable information into the better consideration of the valence state of ruthenium, in these compounds. The thermo-power measurement reveals hole-like conduction mechanism for the thermo-electric transport.

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