scholarly journals Electrical Conductivity Enhancement of V2O5-P2O5-Bi2O3 Glasses by Nanocrystallization

2021 ◽  
Author(s):  
F. A. Ibrahim
Keyword(s):  
Electrical Conductivity ◽  
Glass Ceramic ◽  
Glass Structure ◽  
Dc Conductivity ◽  
Glass System ◽  
X Ray Diffraction ◽  
Conductivity Enhancement ◽  
Average Grain Size ◽  
Structural And Electrical Properties ◽  
Xrd Patterns

AbstractThe structural and electrical properties of the xP2O5-(40 − x) Bi2O3-60V2O5 (0 ≤ x ≤ 20) glass system have been investigated. The samples were prepared by the conventional melt-quenching technique. X-ray diffraction (XRD) patterns confirmed the amorphous nature of the present glasses. Nanocrystalline grains were found due to the annealing of the glass samples under study. Nanocrystals with an average grain size of 22 nm were implanted in the glass structure and estimated from the XRD patterns of the glass–ceramic samples. DC conductivity of the glass system has been determined in the temperature range 300–500 K. It was found that the general behavior of electrical conductivity was similar for all the glass compositions and found to decrease with increasing phosphate content. The electrical conductivity of the glass–ceramic nanocrystals obtained by annealing at crystallization temperature (Tc) was much higher than the initial glass. The activation energy (W) was enhanced by annealing and was obtained from plots of temperature-dependent DC conductivity, and found to be 0.23–0.31 eV for glasses and 0.19–0.23 eV for the glass–ceramic nanocrystals.

Figures of Merit of Low-Cost CuAl0.9Fe0.1O2 Thermoelectric Material Prepared at Different Solid State Reaction Sintering Temperatures

2015 ◽  
Vol 659 ◽  
pp. 185-189
Author(s):  
Aparporn Sakulkalavek ◽  
Rungnapa Thonglamul ◽  
Rachsak Sakdanuphab
Keyword(s):  
Figure Of Merit ◽  
Sintering Temperature ◽  
Low Cost ◽  
Uniaxial Pressure ◽  
Rhombohedral Structure ◽  
Second Phase ◽  
X Ray Diffraction ◽  
High Purity Grade ◽  
Average Grain Size ◽  
Xrd Patterns

In this study, we investigated a CuAl0.9Fe0.1O2 compound prepared at two different sintering temperatures in order to find out the effect of sintering temperature on the compound's figure of merit of thermoelectric properties. The thermoelectric CuAl0.9Fe0.1O2 compound was prepared from high purity grade Cu2O, Al2O3 and Fe2O3 powders. The mixture of these powders were ground and then pressed with uniaxial pressure into pellets. The pellets obtained were sintered in the air at 1423 K and 1473 K. X-ray diffraction (XRD) patterns showed a single phase of CuAl0.9Fe0.1O2 with rhombohedral structure, , along with a trace of CuO second phase. Moreover, the XRD peaks of the sample sintered at 1423 K indicated that more Fe3+ atoms replaced Al3+ atoms in this sample than they did in the sample sintered at 1473 K. The average grain size of the CuAl0.9Fe0.1O2 compound prepared increased with increasing sintering temperature, whereas its mean pore size and porosity decreased with increasing sintering temperature. The dispersed small pores markedly decreased the thermal conductivity of the compound, while the Fe3+ substitution of Al3+ increased its electrical conductivity. The highest figure of merit (ZT) found was 0.021 at 973 K in the CuAl0.9Fe0.1O2 sample sintered at 1423 K. Our findings show that this low-cost material with a reasonable figure of merit is a good candidate for thermoelectric applications at high-temperature.

Transport Properties of B-, P-Doped and Undoped 50 kHz PECVD Microcrystalline Silicon

1989 ◽  
Vol 164 ◽  
Author(s):  
M.A. Hachicha ◽  
Etienne Bustarret
Keyword(s):  
Grain Size ◽  
Hall Mobility ◽  
Solid Phase ◽  
Grazing Angle ◽  
Dc Conductivity ◽  
X Ray Diffraction ◽  
Crystalline Fraction ◽  
Average Grain Size ◽  
20 Nm ◽  
Solid Phase Density

AbstractUndoped 500 nm-thick silicon layers with a crystalline fraction around 95% and an average grain size of 20 nm have been deposited at 350°C by 50 kHz triode PECVD in a H2/SiH4 mixture, in the presence of a magnetic field. Their room temperature (rt) dc conductivity μrt is 0.03 Δ−1cm−1 for a Hall mobility of 0.8 cm 2V−1s−1.The study by SIMS, infrared absorption, grazing angle x-ray diffraction and Raman scattering spectroscopies of the doped samples shows how the crystalline fraction and the grain size drop as the B2H6/SiH4 and PH3/SiH4 volumic ratios increase from 10 ppm to 1%.The rt dc conductivity reaches 2 Δ−1 cm−1 (Hall mobility: 15 cm2V−ls−1) for a solid phase density of 1019 cm−3 boron atoms, and 30 Δ−1cm−1 (Hall mobility: 55 cm2V−ls−1) at the maximum P incorporation of 8 × 1020cm−3.

scholarly journals OPTICAL PROPERTIES ON Li2O-K2O-WO3-B2O3 GLASS SYSTEM

2013 ◽  
Vol 22 ◽  
pp. 278-283
Author(s):  
A. EDUKONDALU ◽  
M. A. SAMEE ◽  
SHAIKH KAREEM AHMMAD ◽  
SAIR MD. TAQIULLAH ◽  
SYED RAHMAN ◽  
...  
Keyword(s):  
Glass Structure ◽  
Glass System ◽  
Alkali Concentration ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Mixed Alkali ◽  
Absorption Studies ◽  
Mixed Alkali Effect ◽  
Oxide Ion ◽  
B2o3 Glass

Mixed alkali tungsten borate glasses xLi2O–(30–x) K2O–10WO3–60B2O3 (0 < x < 30) were prepared from the melts. These glasses were characterized using X-ray diffraction, differential scanning calorimetry and density measurements. Optical absorption studies were carried out as a function of alkali content to look for mixed alkali effect (MAE) on the spectral properties of these glasses. From the study of ultraviolet absorption edge, the optical band gap energies and Urbach energies were evaluated. The average electronic polarizability of the oxide ion, optical basicity and the interaction parameters were also evaluated for all the glasses. Many of these parameters vary non-linearly exhibiting a minima or maxima with increasing alkali concentration, indicating the mixed alkali effect. An attempt is made to interpret MAE in this glass system in terms of its glass structure.

Structure and Electrical Properties of BNKT-Based Ceramics

2018 ◽  
Vol 283 ◽  
pp. 147-153 ◽  
Author(s):  
Supalak Manotham ◽  
Pichitchai Butnoi ◽  
Pharatree Jaita ◽  
Tawee Tunkasiri
Keyword(s):  
Grain Size ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Tetragonal Symmetry ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Average Grain Size ◽  
Influence Of Temperature On ◽  
Polarization Electric Field ◽  
Xrd Patterns

In this work, the properties of lead-free 0.92(Bi0.5Na0.42K0.08)TiO3-0.08(BaNb0.01Ti0.99)O3 or 92BNKT-8BNbT ceramic has been investigated. The sample was fabricated by a solid-state reaction technique. The 92BNKT-8BNbT sample was well sintered and dense with high density value of 5.86 g/cm3. X-Ray diffraction (XRD) patterns showed a single perovskite phase with tetragonal symmetry and no impurity or secondary phases. The microstructure was analysed using a scanning electron microscopy (SEM). Average grain size was measured and calculated based on a mean linear intercept method. The ceramics had a cubic-like grain shape with an average grain size of 0.39 µm. The influence of temperature on the dielectric and ferroelectric properties of the ceramic was investigated. The dielectric curves exhibited broad transition peaks at Td and Tm, which were the characteristics of a diffuse phase transition. The polarization-electric field (P-E) hysteresis loop changed from well-saturated at room temperature (RT) to pinched-type loop at high temperature (HT) and the remanent polarization decreased from 21.25 µC/cm2 (at RT) to 5.96 µC/cm2 (at 150 °C).

scholarly journals Synthesis, Crystallization, and Dielectric Behaviour of Lead Bismuth Titanate Borosilicate Glasses with Addition of 1% La2O3

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
C. R. Gautam ◽  
Abhishek Madheshiya ◽  
R. K. Dwivedi
Keyword(s):  
Glass Ceramic ◽  
Bismuth Titanate ◽  
Glass System ◽  
Glassy Matrix ◽  
Borosilicate Glasses ◽  
X Ray Diffraction ◽  
Mole Percent ◽  
Ceramic Samples ◽  
Donor Dopant ◽  
Quench Method

Lead bismuth titanate borosilicate glasses were prepared in the glass system 65[(PbxBi1-x)·TiO3]-34[2SiO2·B2O3]-1La2O3 (0.0≤x≤1.0) doped with one mole percent of La2O3 via conventional melt quench method. The amorphous nature of glass samples in this glass system is confirmed by using X-ray diffraction (XRD) study. Differential thermal analysis (DTA) has been employed to determine the glass transition temperature, Tg, as well as crystallization temperature, Tc. DTA measurements were recorded in temperature range from 30 to 1200°C. The prepared glasses were crystallized by regulated controlled heat treatment process on the basis of their DTA results. These samples are carried out for XRD measurements in the 2θ range from 20 to 80° to study the crystallization behaviour and phase formation of the glass ceramic samples. The scanning electron microscopy (SEM) of these glass ceramic samples has been carried out to explore the morphology through nucleation and growth of the crystallites in the glassy matrix. The values of dielectric constant as well as dielectric loss were increased with increasing the temperature within the frequency range from 20 Hz to 100 Hz. The addition of 1 mol% of La2O3 to the lead bismuth titanate glasses enhances the crystallization and acts as donor dopant for this glass system.

ELECTRICAL PROPERTY OF CONVENTIONALLY SINTERED ZnO

2013 ◽  
Vol 22 ◽  
pp. 501-510 ◽  
Author(s):  
S. K. TAK ◽  
M. S. SHEKHWAT ◽  
R. MANGAL
Keyword(s):  
Sintering Temperature ◽  
Hold Time ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Phase Study ◽  
Average Grain Size ◽  
Structural And Electrical Properties ◽  
Different Temperatures ◽  
Zno Powder ◽  
Zno Ceramics

ZnO powder was synthesized by solid state reaction method. The synthesized powder was granulated and pressed using uni-axial press for preparing the pallets. The prepared pellets were sintered in conventional furnace at different temperatures (900-1300° C). The phase study was done by powder X-ray diffraction and it was found that the there is no other phase present in the synthesized material but the peak intensity is increasing with temperature. The crystallite size of the synthesized ZnO powder was found to be increase with temperature. The effect of sintering on grain growth is investigated by scanning electron microscopy (SEM). SEM revels that the average grain size is increases with increase in sintering temperature. AC impedance of these samples was decreased markedly with increased sintering temperature. In present work the effect of sintering temperatures and hold time on micro structural and electrical properties of ZnO ceramics is carried out.

Non-Stoichiometry and Structure of SrCe1-xYbxO3 Perovskite-Type Oxides

1996 ◽  
Vol 453 ◽  
Author(s):  
Igor Kosacki ◽  
Mark Shumsky ◽  
Harlan U. Anderson
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Charge Carrier ◽  
Structural Properties ◽  
Electrical Transport ◽  
Structural Disorder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Electrical Properties ◽  
Perovskite Type

AbstractThe structural and electrical properties of SrCe1-xYbxO3 ceramics have been studied as a function of temperature and Yb-concentration using x-ray diffraction and impedance techniques. The influence of Yb-dopants on electrical transport and structural disorder has been studied. A correlation between the structural properties, electrical conductivity is observed and discussed. These measurements allow us to determine the mechanism of charge carrier compensation and also the concentration and mobility of the electrical species.

Sol–gel synthesis, structural and electrical properties of Li2CoSiO4 cathode material

2014 ◽  
Vol 07 (06) ◽  
pp. 1440001 ◽  
Author(s):  
Michał Świętosławski ◽  
Marcin Molenda ◽  
Piotr Natkański ◽  
Piotr Kuśtrowski ◽  
Roman Dziembaj ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Sol Gel ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Structural And Electrical Properties ◽  
Potential Alternative ◽  
Sol Gel Synthesis ◽  
First Time

Polyanionic cathode materials for lithium-ion batteries start to be considered as potential alternative for layered oxide materials. Among them, Li 2 CoSiO 4, characterized by outstanding capacity and working voltage, seems to be an interesting substitute for LiFePO 4 and related systems. In this work, structural and electrical investigations of Li 2 CoSiO 4 obtained by sol–gel synthesis were presented. Thermal decomposition of gel precursor was studied using EGA (FTIR)-TGA method. Chemical composition of the obtained material was confirmed using X-ray diffraction and energy-dispersive X-ray spectroscopy. The morphology of β- Li 2 CoSiO 4 was studied using transmission electron microscopy. High temperature electrical conductivity of Li 2 CoSiO 4 was measured for the first time. Activation energies of the electrical conductivity of two Li 2 CoSiO 4 polymorphs (β and γ) were determined. The room temperature electrical conductivity of those materials was estimated as well.

Structural Characterization of a Glass Ceramic Developed from TiO2 and a Novel Material-Silica Xerogel Converted from Sago Waste Ash

2016 ◽  
Vol 872 ◽  
pp. 81-86 ◽  
Author(s):  
Haji Aripin ◽  
Seitaro Mitsudo ◽  
I Nyoman Sudiana ◽  
Nundang Busaeri ◽  
Bambang Sunendar ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Silica Xerogel ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
Vis Spectroscopy ◽  
Novel Material ◽  
Synthesis Procedure ◽  
Sago Waste ◽  
Xrd Patterns

In this paper, we present the synthesis procedure and the results of an investigation of a novel silica xerogel (SX) glass ceramic developed from an amorphous SX derived from sago waste ash that incorporates TiO2 as an additive. The studied compositions have been prepared by adding of either 20% or 80 wt% of TiO2 into SX, respectively. The samples have been dry pressed and sintered in the temperature range between 900°C and 1500°C. Their properties have been characterized on the basis of the experimental data obtained using X-ray diffraction (XRD), Fourier transform infrared (FTIR), and ultraviolet-visible (UV-Vis) spectroscopy. It has been found that an increase of the content of SX in the composition leads to an increase of the shift of the bandgap energy of TiO2. The analysis based on the interpretation of both XRD patterns and FTIR spectrum allows one to explain the shift in the bandgap energy by an enlargement of the crystallite size of TiO2 and by forming of more Si–O–Ti bonds in the samples with a smaller loading of TiO2.

Ionic conductivity enhancement in Gd2Zr2O7 pyrochlore by Nd doping

2008 ◽  
Vol 23 (4) ◽  
pp. 911-916 ◽  
Author(s):  
B.P. Mandal ◽  
S.K. Deshpande ◽  
A.K. Tyagi
Keyword(s):  
Activation Energy ◽  
Ionic Conductivity ◽  
Preexponential Factor ◽  
Dc Conductivity ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
Conductivity Enhancement ◽  
Mobile Species ◽  
Oxygen Ion ◽  
Mobile Ions

The pyrochlore compositions Gd2–yNdyZr2O7 (y = 0.0, 0.1, 0.4, 0.6, 1.0, 1.4, 1.6, and 2.0) were synthesized, and their ionic conductivity was determined (100 Hz–15 MHz, 622–696 K). The direct-current (dc) conductivity (σdc) varies upon Nd substitution at the Gd site, and a peaking effect in σdc was observed around y = 1.0. This indicates that a significant increase in conductivity can be obtained at moderately high temperatures by suitable doping at the Gd site with isovalent rare-earth ions like Nd. The extent of oxygen ion disorder determined from x-ray diffraction was found to decrease with increasing Nd content. The dc conductivity obeys the Arrhenius relation σdcT = σ0 exp(−E/kBT). The activation energy E and the preexponential factor σ0, which is a measure of the concentration of the mobile species, increase while going from the ordered Nd2Zr2O7 to the least ordered Gd2Zr2O7. These two processes presumably lead to the peaking of σdc at an intermediate Nd content. Our results also suggest that the cooperative motion of mobile ions does not contribute much to the increase in activation energy in this compound.

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