Effect of MCl (M = Na, K) addition on microstructure and electrical conductivity of forsterite

Forsterite single phase powder Mg2SiO4 was synthesized by sol–gel method alongside with heat treatment, using two different cation alkaline salts MCl as mineralizers (M = Na, K) with various mass percentages (2.5, 5, 7.5, and 10 wt.%). In this work, we report on the effect of the cation type and the added amount of used mineralizer on microstructure and electrical conductivity of Mg2SiO4. The formation of forsterite started at 680–740 °C and at 630–700 °C with KCl and NaCl respectively, as shown by TG-DTA and confirmed by XRD. Furthermore, the Fourier transform infrared (FTIR) transmission spectra indicated bands corresponding to vibrations of forsterite structure. The morphology and elemental composition of sintered ceramics were examined by SEM-EDX analyses, while their densities, which were measured by Archimedes method, increased with addition of both alkaline salts. The electrical measurements were performed by Complex Impedance Spectroscopy. The results showed that electrical conductivity increased with the addition of both mineralizers, which was higher for samples prepared with NaCl than those prepared with KCl.

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Sol-gel processing of cordierite: Effect of seeding and optimization of heat treatment

Journal of Materials Research ◽

10.1557/jmr.1990.1095 ◽

1990 ◽

Vol 5 (5) ◽

pp. 1095-1103 ◽

Cited By ~ 44

Author(s):

Ann M. Kazakos ◽

Sridhar Komarneni ◽

Rustum Roy

Keyword(s):

Heat Treatment ◽

Single Phase ◽

Excess Free Energy ◽

Sol Gel ◽

Nucleating Agents ◽

Optimum Conditions ◽

Nanosized Powders ◽

Nanocomposite Gels ◽

Powder Compacts ◽

Gel Processing

Three series of cordierite powders were prepared by the sol-gel route: a single phase (monophasic) gel prepared from alkoxides, a nominally triphasic nanocomposite gel made with two nanosized powders and one solution phase, and a truly compositionally triphasic nanocomposite gel prepared from three nanosized powders. Crystalline α-cordierite seeds were also incorporated with the gels and their effectiveness as nucleating agents was investigated and found to lower the crystallization temperature of α-cordierite by 125–150°C. The densification behavior of powder compacts was examined and alterations made to the heat treatment until optimum conditions were found. The truly triphasic compact sintered at 1300°C for 2 h resulted in 100% of theoretical density whereas the nominally triphasic and monophasis pellets densified to 96% and 80%, respectively. The enhanced densification achieved with powder compacct prepared for triphasic nanocomposite gels is due to part to the excess free energy of the three components.

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Electrochemical Performance of La0.7Sr0.3Cu1-xFexO3-δ as Cathode Material in IT-SOFCs

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.160-162.666 ◽

2010 ◽

Vol 160-162 ◽

pp. 666-670

Author(s):

Min Zhang Zheng ◽

Xiao Mei Liu

Keyword(s):

Electrical Conductivity ◽

High Temperature ◽

Cathode Material ◽

Single Phase ◽

Cathodic Polarization ◽

Sol Gel ◽

X Ray Diffraction ◽

X Ray ◽

Cathodic Overpotential ◽

A Current

To obtain more detail information about the cathode of La0.7Sr0.3Cu1-xFexO3-δ（x= 0.1,0.3,0.5,0.7,0.9）in IT-SOFCs, the cathode material La0.7Sr0.3Cu1-xFexO3-δ（x=0.1, 0.3, 0.5, 0.7, 0.9）was synthesized by a sol-gel method. X-ray diffraction revealed it to be form a single phase of perovskite. The high temperature electrical conductivity was measured by using the four-point dc technique, and cathodic overpotential with SDC（Sm0.15Ce0.85O1.925） electrolyte support was measured by using a current-interruption technique. The investigation of electrocheimical properties suggested that La0.7Sr0.3Cu0.7Fe0.3O3-δ has the highest electrical conductivity and the lowest cathodic polarization. Using La0.7Sr0.3Cu0.7Fe0.3O3-δ as cathode and 65%NiO/SDC as anode based on SDC electrolyte one can obtain higher current density and power density at intermediate temperatures, La0.7Sr0.3Cu0.7Fe0.3O3-δ is considered to be a possible cathode adapted to IT-SOFCs.

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Experimental and Theoretical Study of Electrical Conductivity of Intermetallic and Nanocomposites: Subzero Temperature Superconductor

10.21203/rs.3.rs-215710/v1 ◽

2021 ◽

Author(s):

Harish Kumar ◽

Aarti Bhateria ◽

Bhupender Singh ◽

Pawanvir Kaur

Keyword(s):

Heat Treatment ◽

Electrical Conductivity ◽

Computational Study ◽

Sol Gel ◽

Ferromagnetic Material ◽

Treatment Temperature ◽

Subzero Temperature ◽

Coinage Metal ◽

Potential Applications ◽

Xrd Techniques

Abstract A comparative study of the electrical conductivity of intermetallic and corresponding nanocomposites at room and the subzero temperature was carried out by experimental and theoretical techniques. Four series of intermetallic compounds (IMCs) and nanocomposites (NCs) of Al2O3, ZnO, TiO2, and CuO were synthesized by high-temperature reactive synthesis and sol-gel technique, respectively. Heat treatment of NCs was carried out at 100, 200, 300, and 400°C. Characterization of NCs was carried out by UV-visible, FTIR, FE-SEM, and XRD techniques. Computational study (DMol3, CASTEP, Forcite, Reflex, and VAMP) was carried out to study the electronic and optical properties of metal nanoparticles. The influence of heat treatment, the addition of coinage metal and ferromagnetic material, effect of a decrease in temperature on the electrical conductivity of IMCs and NCs were thoroughly investigated. The electrical conductivity of NCs was found to increase with an increase in heat treatment temperature (up to 400°C) and with the decrease in temperature (-70°C). The addition of Hematite, α-Fe2O3, and coinage metal do not significantly increase the electrical conductivity of NCs at room temperature. The electrical conductivity of NCs was found to be higher than IMCs and coinage metals. Hence, synthesized NCs can have a large number of potential applications in nanowires, quantum dots, and nano cables with very low resistivity (10-6 ΩWm-1).

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Electrical, dielectric and photocatalytic properties of Fe-doped ZnO nanomaterials synthesized by sol gel method

Processing and Application of Ceramics ◽

10.2298/pac1603125c ◽

2016 ◽

Vol 10 (3) ◽

pp. 125-135 ◽

Cited By ~ 22

Author(s):

Yacine Cherifi ◽

Ahcène Chaouchi ◽

Yannick Lorgoilloux ◽

Mohammed Rguiti ◽

Abdelaziz Kadri ◽

...

Keyword(s):

Single Phase ◽

Uv Light ◽

Sol Gel ◽

Complex Impedance ◽

Hexagonal Wurtzite Structure ◽

Band Gap Energy ◽

Cbh Model ◽

Gap Energy ◽

Gel Technique ◽

Doped Zno

Fe-doped ZnO nanoparticles were synthesized by sol gel technique. Fine-scale and single phase hexagonal wurtzite structure in all samples were confirmed by SEM and XRD, respectively. The band gap energy depends on the amount of Fe and was found to be in the range of 3.11-2.53 eV. The electric and dielectric properties were investigated using complex impedance spectroscopy. AC conductivity data were correlated with the barrier hopping (CBH) model to evaluate the binding energy (Wm), the minimum hopping distance (Rmin) and the density of states at Fermi level, N(EF). Fe doping in ZnO also improved the photocatalytic activity. Thus, the sample Zn0.95Fe0.05O showed high degradation potential towards methylene blue (MB), i.e. it degrades 90% of BM in 90min under UV light.

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Evaluation of structure, dielectric and electrical properties of (Li/Ta/Sb) modified (Na, K) NbO3 lead-free ceramics with excess Na concentration

Journal of Advanced Dielectrics ◽

10.1142/s2010135x17500370 ◽

2017 ◽

Vol 07 (06) ◽

pp. 1750037 ◽

Cited By ~ 1

Author(s):

Md. Kashif Shamim ◽

Arpana Singh ◽

Seema Sharma

Keyword(s):

Single Phase ◽

Ferroelectric Properties ◽

Structural Phase ◽

Complex Impedance ◽

Negative Temperature ◽

X Ray Diffraction ◽

Electrical Measurements ◽

Lead Free Ceramics ◽

Raman Modes

Polycrystalline perovskite structured (Li[Formula: see text] (Na[Formula: see text] K[Formula: see text])[Formula: see text] (Nb[Formula: see text]Ta[Formula: see text] Sb[Formula: see text] O3 ceramics with [Formula: see text], 0.005 and 0.01 mole excess Na concentration were prepared by solid state sintering method. The present study relates the role of excess Na addition with the stoichiometry, density, structure, dielectric and ferroelectric properties of the samples. X-ray diffraction (XRD) pattern exhibits single phase orthorhombic structure. The characteristic Raman modes were observed due to translational modes of cations and vibrational modes of NbO6 octahedra and no structural phase transition were observed. This confirms the formation of single phase perovskite structure and is consistent with XRD results. The dielectric permittivity increases about two times, while dielectric loss decreases by four times for [Formula: see text] composition. The electrical measurements carried by Complex Impedance spectroscopic analysis suggest negative temperature coefficient of resistance (NTCR) behavior.

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Effect of Ni2+substitution on the Structural, Magnetic and Dielectric Properties of PbFe12-xNixO19 Nanoparticles

10.21203/rs.3.rs-74828/v1 ◽

2020 ◽

Author(s):

seyed ebrahim Mousavi Ghahfarokhi ◽

Foruzan Bazdar ◽

Iraj Kazeminezhad ◽

Elham Mohammadzadeh Shobegar

Keyword(s):

Electrical Conductivity ◽

Dielectric Properties ◽

Single Phase ◽

Spinel Ferrite ◽

Sol Gel ◽

Sem Images ◽

Ac Electrical Conductivity ◽

Field Frequency ◽

Magnetic And Dielectric Properties ◽

Lcr Meter

Abstract PbFe12-xNixO19 nanoparticles (x = 0-1) were prepared by a sol–gel method. The influence of Ni2+ substitution on structural, magnetic and dielectric properties of PbFe12O19 nanoparticles was investigated. The samples of PbFe12-xNixO19 nanoparticles have been characterized by the X-ray diffractomere (XRD), Fourier transform infrared spectrometer (FT-IR), scanning electron spectrometer (SEM), vibrating sample magnetometer (VSM), and an LCR meter. The results reveal that PbFe12-xNixO19 compounds up to x = 0.2 are single phase. The bands of absorption in the 400– 500 cm-1 and the bands of absorption in the range of 500 -600 cm-1, corresponding to the formation of octahedral and tetrahedral sites which confirms the presence of metal– oxygen stretching band in ferrites. Also, SEM images show that by increasing Ni2+ doping grains size have been increased. However, for x > 0.2, the secondary Ni spinel ferrite (NiFe2O4) appears which the saturation magnetization and magnetic coercivity decreases. In addition, Ni2+substitution reduces the dielectric constant, dielectric loss, and ac electrical conductivity for all samples decrease rapidly with increasing applied field frequency and reaches a constant value beyond a certain frequency which this is characteristic of the normal dielectric behaviour of ferrites and has been investigated by Maxwell–Wagner’s two-layer model and Koop’s theory. The variation in ac conductivity (σac) with frequency shows that the electrical conductivity in these ferrites is mainly attributed to the electron hopping mechanism.Therefore; all single-phase Ni2+ substituted samples are suitable for use in magnetic recording media and microwave devices.

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Sol-gel derived Nd1/3La1/3Ca1/3MnO3: Phase evolution and preparation of films and nanopowders

Journal of Materials Research ◽

10.1557/jmr.2007.0221 ◽

2007 ◽

Vol 22 (6) ◽

pp. 1737-1743 ◽

Cited By ~ 1

Author(s):

A. Pohl ◽

G. Westin

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Single Phase ◽

Sol Gel ◽

Phase Evolution ◽

Perovskite Oxide ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Cell Parameters ◽

Transmission Electron

An all-alkoxide sol-gel route to the formation of Nd1/3La1/3Ca1/3MnO3thin films and powders has been developed. The microstructural evolution on heat treatment of the gel to yield the perovskite oxide was monitored by means of thermogravimetric analysis-differential scanning calorimetry, powder x-ray diffraction (XRD), Fourier transform infrared spectroscopy, and transmission electron microscopy (TEM)-energy dispersive spectroscopy (EDS). It was found that the amorphous gel consists of hydrated oxo-carbonate without organic residues, and on heating it decomposes in several steps, finally forming single-phase perovskite at 680 °C. Further heating results in only slight changes in the cell parameters and crystal growth. Films were prepared by spin coating, followed by heat treatment in air to a temperature of 800 °C, and studied by scanning electron microscopy, TEM-EDS, and XRD. Films on Al2O3were more porous, while films on Pt–TiO2–SiO2–Si were rather dense and consisted of areas with different crystal orientations.

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Microstructural development in sol-gel derived lead zirconate titanate thin films: The role of precursor stoichiometry and processing environment

Journal of Materials Research ◽

10.1557/jmr.1996.0261 ◽

1996 ◽

Vol 11 (8) ◽

pp. 2076-2084 ◽

Cited By ~ 78

Author(s):

M. J. Lefevre ◽

J. S. Speck ◽

R. W. Schwartz ◽

D. Dimos ◽

S. J. Lockwood

Keyword(s):

Thin Films ◽

Heat Treatment ◽

Lead Zirconate Titanate ◽

Single Phase ◽

Perovskite Phase ◽

Sol Gel ◽

Lead Zirconate ◽

Microstructural Development ◽

Zirconate Titanate

The role of precursor stoichiometry and local firing environment on the microstructural development of sol-gel derived lead zirconate titanate (PZT) thin films was investigated. Typically, excess Pb is added to films to compensate for PbO volatilization during heat treatment. Here, it is shown that the use of stoichiometric precursors with either a PbO atmosphere powder or a PbO overcoat during the crystallization heat treatment is an attractive and viable alternative method for control of film stoichiometry. Using these approaches, we have fabricated single phase perovskite thin films with microstructures and electrical properties (Pr ∼ 36 μC/cm2 and Ec ∼ 45 kV /cm) comparable to those of films using optimized solution chemistries and excess Pb additions. The potential advantage of increasing PbO partial pressure, or activity, during firing versus excess Pb additions is discussed from the standpoint of a proposed crystallization scenario based on the kinetic competition between Pb loss and the nucleation and growth rates of the perovskite phase.

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Sol-gel Autocombustion Elaboration and Physiochemical Characterizations of Cu2+ Substituted Cobalt Ferrite Nanoparticles

Open Chemistry Journal ◽

10.2174/1874842202007010044 ◽

2020 ◽

Vol 7 (1) ◽

pp. 44-54

Author(s):

N. Hamdi ◽

L. Bessais ◽

W. Belam

Keyword(s):

Electrical Conductivity ◽

Quantum Interference ◽

Cobalt Ferrite ◽

Magnetic Measurement ◽

Sol Gel ◽

Complex Impedance ◽

Basic Structure ◽

Host Lattice ◽

X Ray ◽

Substitution Procedure

Introduction: The copper doped cobalt ferrite series, with nominal formula CuXCo1-XFe2O4 (X = 0, 0.25, 0.5, 0.75, 1), has been elaborated via sol-gel autocombustion process by copper substitution procedure into cobalt ferrite framework. Methods: The five synthesized ferrites have been analyzed by X-ray powder diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy coupled to energy dispersive X-ray spectroscopy, complex impedance spectroscopy and superconducting quantum interference device magnetometry. Results and Discussion: The analysis of the results allowed to deduce that the cubic spinel basic structure was not modified by the incorporation of copper into the host lattice and the corresponding pure fine powders obtained formed by homogeneous nanoparticles. The highest electrical conductivity value, σDC(373K) = 27.03x10-3S.cm-1, was observed in the case of CuFe2O4. Conclusion: Moreover, the superparamagnetic behavior at room temperature has been confirmed by using both ZFC-FC and hysteresis magnetic measurement modes. In addition, the remarkable electrical conductivity and magnetic properties of the five explored nanoferrites, derived from the present investigation, enabled them useful in several modern nanotechnological and biomedical applications.

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Electrical Properties of La0.7Sr0.3CuO3-δCathode Based on SDC-YSZ Composite Electrolyte

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.702.224 ◽

2013 ◽

Vol 702 ◽

pp. 224-228

Author(s):

Min Zhang Zheng ◽

Xiao Mei Liu

Keyword(s):

Electrical Conductivity ◽

Single Phase ◽

High Current Density ◽

Sol Gel ◽

High Current ◽

X Ray Diffraction ◽

Composite Electrolyte ◽

X Ray ◽

Cathodic Overpotential ◽

A Current

The cathode material La0.7Sr0.3CuO3-δ was synthesized by a sol-gel method. X-ray diffraction revealed it to be form a single phase of perovskite. The SDC（Sm0.15Ce0.85O1.925）was synthesized by glycine-nitrate processes. The 90%SDC and 10%YSZ powders are mixed to prepare as SDC-YSZ composite electrolyte. The high temperature electrical conductivity of La0.7Sr0.3CuO3-δ was measured by using the four-point dc technique, and cathodic overpotential with SDC-YSZ composite electrolyte support was measured by using a current-interruption technique. Using La0.7Sr0.3CuO3-δ as cathode and 65%NiO/SDC as anode based on SDC-YSZ composite electrolyte one can obtain high current density and power density at intermediate temperatures.

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