Experimental Study on Electrical Conductivity of FexO-CaO-SiO2-Al2O3 System at Various Oxygen Potentials

2018 ◽  
Vol 37 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Yan–Xiang Liu ◽  
Jun–Hao Liu ◽  
Guo–Hua Zhang ◽  
Jian–Liang Zhang ◽  
Kuo–Chih Chou
Keyword(s):  
Electrical Conductivity ◽  
Ionic Conductivity ◽  
Oxygen Potential ◽  
Electronic Conductivity ◽  
Transference Number ◽  
Free Oxygen ◽  
Total Electrical Conductivity ◽  
Oxygen Ion ◽  
Conductivity Increase ◽  
Temperature Dependences

AbstractThe electrical conductivity of FexO-CaO-SiO2-Al2O3 slags was measured by a four terminal method. The results show that the temperature dependences of total, electronic and ionic conductivity for different compositions obey the Arrhenius law and all of them increase as increasing the temperature. For all the studied slags, as increasing CO/CO2 ratio which is used to controlled the oxygen potential, both the total electrical conductivity and electronic conductivity increase, but the ionic conductivity decreases. It was also found that the electronic transference number exhibits a strong correlation with oxygen potential, but is independent of temperature. Under the condition of constant FexO content, the higher the basicity of slags is, the higher the total electrical conductivity and ionic/electronic conductivity will be, which is resulted from the increase of free oxygen ion.

Electrical Properties of Y0.06Sr0.94Ti0.6Fe0.4O3-δ-YSZ Composites as Electrode Materials

2016 ◽  
Vol 697 ◽  
pp. 327-330 ◽  
Author(s):  
Ke Shan ◽  
Xing Min Guo ◽  
Feng Rui Zhai ◽  
Zhong Zhou Yi
Keyword(s):  
Electrical Conductivity ◽  
Electrode Materials ◽  
Electronic Conductivity ◽  
Ionic Conductivities ◽  
Conductivity Measurement ◽  
Transference Numbers ◽  
Secondary Phases ◽  
Electrical Conductivity Measurement ◽  
Total Electrical Conductivity ◽  
Phase Compatibility

Y0.06Sr0.94Ti0.6Fe0.4O3-δ-YSZ composites were prepared by mixing Y, Fe co-doped SrTiO3 (Y0.06Sr0.94Ti0.6Fe0.4O3-δ known as YSTF) and 8 mol% Y2O3 stabilized ZrO2 (YSZ) in different weight fractions. The phase stability, phase compatibility, microstructure and mixed ionic-electronic conductivity of composites were investigated. Phase analysis by XRD showed no clearly detectable secondary phases. The electrical conductivity measurement on the YSTF-YSZ composites showed a drastic decrease in total electrical and ionic conductivities when more than 10 wt% of YSZ was used in the composites. The total electrical conductivity was 0.102 S/cm for Y0.06Sr0.94Ti0.6Fe0.4O3-δ and 0.043 S/cm for YSTF-20YSZ at 700 oC, respectively. The value at 700 oC is approximately 2.4 times higher than that of YSTF-20YSZ. The ionic conductivity of Y0.06Sr0.94Ti0.8Fe0.2O3-δ varies from 0.015S/cm at 700 oC to 0.02 S/cm at 800 oC, respectively. The value at 800°C is approximately 12.5 times higher than YSTF-20YSZ. The ion transference numbers of YSTF-YSZ composites vary from 0.14 to 0.28 at 800 °C.

Coordination polymer-based conductive materials: ionic conductivity vs. electronic conductivity

2019 ◽  
Vol 7 (42) ◽  
pp. 24059-24091 ◽  
Author(s):  
Hai-Ning Wang ◽  
Xing Meng ◽  
Long-Zhang Dong ◽  
Yifa Chen ◽  
Shun-Li Li ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Ionic Conductivity ◽  
Coordination Polymer ◽  
Coordination Polymers ◽  
Electronic Conductivity ◽  
Structural Factors ◽  
Conductive Materials ◽  
Recent Developments

This review summarizes recent developments of coordination polymers and their derivatives for ionic and electrical conductivity with the discussion about synthetic strategies and possible mechanisms to identify the key structural factors.

Electrical Conductivity of Mixed Conductors (YO1.5)x-(CeO2)y-(ZrO2)1-x-y

2007 ◽  
Vol 336-338 ◽  
pp. 424-427
Author(s):  
Xiang Yong Zhou ◽  
Zeng Fan ◽  
Zi Long Tang ◽  
Zhong Tai Zhang
Keyword(s):  
Electrical Conductivity ◽  
Metal Ion ◽  
Solid Phase ◽  
Electronic Conductivity ◽  
Synthesis Method ◽  
Conductivity Measurement ◽  
Fluorite Structure ◽  
Charge Balance ◽  
Phase Synthesis ◽  
Oxygen Ion

The Y2O3-ZrO2 binary system ceramic is considered to be most developed in application to the ZrO2-based materials. A cubic fluorite structure is generally achieved, as the metal ion of the additive (Y) takes place of the Zr4+ and oxygen ion vacancies are produced in the lattice to maintain the charge balance. This leads to almost totally ionic conductivity. The introduction of changeable valued CeO2 can further improve the total electronic conductivity through the defect equilibrium reaction between tetravalent Ce4+ and trivalent Ce3+ at high temperature and reducing atmosphere. In this study, solid phase synthesis method was employed for the preparation of (YO1.5)x-(CeO2)0.08-(ZrO2)0.9-x and (YO1.5)0.05-(CeO2)y- (ZrO2)0.95-y ceramics, while four probe DC conductivity measurement method was also applied under the temperature between 300 to 800°C. The results prove that the concentration of Y3+ is the main contribution of the electrical conductivity at low temperature.

Preparation and characterization of compounds in the BaBiO3–Ba(Ce1-xGdx)O3-x/2 system

1999 ◽  
Vol 14 (1) ◽  
pp. 124-131 ◽  
Author(s):  
R. Mukundan ◽  
P. K. Davies ◽  
W. L. Worrell
Keyword(s):  
Ionic Conductivity ◽  
Elevated Temperatures ◽  
Electronic Conductivity ◽  
Mixed Valence ◽  
Type Model ◽  
Pseudobinary System ◽  
Conducting Oxides ◽  
Oxygen Ion ◽  
Reducing Conditions ◽  
Electronic Conductivities

The structure, nonstoichiometry, and electrical conductivity of compositions in the BaBiO3– Ba(Ce1-xGdx)O3-x/2 system have been investigated in an attempt to prepare new mixed (ionic-electronic) conducting oxides. The substitution of Bi into Ba(Ce1-xGdx)O3-x/2 decreases the concentration of oxygen-ion vacancies, and the effective negative charge of the Gd dopant is compensated by the mixed valence of Bi (3+, 5+). For low Bi contents a decrease in ionic conductivity decreases the overall conductivity; however, higher levels of Bi introduce significant electronic conductivity, and for Ba(Bi0.5Ce0.5)O3, σtotal ≈ 1 S/cm at 800 °C in air. Compositions in the Ba(Bi0.5Ce0.5-xGdx)O3 pseudobinary system undergo a B-cation order-disorder transformation at 1300–1350 °C for x = 0.5 and at ≈1250 °C for x = 0.4; all other compositions retain a disordered B-site arrangement. While these disordered perovskites exhibit oxygen nonstoichiometry under reducing conditions at elevated temperatures, with the extent of reduction decreasing with increasing Gd content, their ordered counterparts remain close to stoichiometry. The electronic conductivities of this pseudobinary could be fitted to a “band-type” model, and, despite the presence of oxygen vacancies for the lower values of x, no significant ionic conductivity was observed.

scholarly journals Influence of cation substitution on electrical conductivity of microcrystalline ceramics based on (Cu1-xAgx)7GeSe5I solid solutions

2021 ◽  
Vol 24 (02) ◽  
pp. 131-138
Author(s):  
I.P. Studenyak ◽  
◽  
A.I. Pogodin ◽  
V.I. Studenyak ◽  
T.O. Malakhovska ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Solid Solutions ◽  
Electronic Conductivity ◽  
Microstructural Analysis ◽  
Cation Substitution ◽  
Cationic Sublattice ◽  
Total Electrical Conductivity ◽  
Complex Process ◽  
Nonlinear Character ◽  
Average Size

Ceramic samples based on the microcrystalline powders (Cu1–хAgx)7GeSe5I (x = 0, 0.25, 0.5, 0.75, 1) were prepared by pressing them at the pressure close to 400 MPa and subsequent annealing at 873 K for 36 hours. Using the microstructural analysis, the average size of microcrystallites of these samples was determined. Investigation of electrical conductivity of ceramics based on (Cu1 хAgx)7GeSe5I solid solutions was carried out using the method of impedance spectroscopy in the frequency range from 10 Hz to 3×105 Hz and within the temperature range 293...383 K. Analysis of the Nyquist plots allowed determining the contributions of ionic and electronic components to the total electrical conductivity. The temperature dependence of ionic and electronic conductivity in Arrhenius coordinates is linear, which indicates their thermoactivation character. The compositional behaviour of ionic and electronic conductivity, as well as their activation energies have been studied. Their nonlinear character can be explained by the complex process of recrystallization and Cu+ ↔ Ag+ cation substitution within the cationic sublattice.

scholarly journals Preparation and electrical conductivity of (Cu0.5Ag0.5)7SiS5I-based superionic ceramics

2020 ◽  
Author(s):  
Ihor Studenyak ◽  
Artem POGODIN ◽  
Iryna SHENDER ◽  
Serhiy BEREZNYUK ◽  
Mykhailo FILEP ◽  
...  
Keyword(s):  
Solid Solution ◽  
Electrical Conductivity ◽  
Electronic Conductivity ◽  
Microstructural Analysis ◽  
Structural Studies ◽  
Frequency Range ◽  
Electronic Components ◽  
Total Electrical Conductivity ◽  
Ceramic Samples ◽  
Average Size

Abstract The ceramics based on (Cu0.5Ag0.5)7SiS5I solid solution of superionic conductor with argyrodite structure were prepared by using the powders with different particles size. The structural studies of powders were performed by XRD technique, while the ceramic samples with different average size of the crystallites were investigated by microstructural analysis. The total electrical conductivity of ceramic samples was measured by impedance spectroscopy in the frequency range from 10 Hz to 2×106 Hz and temperature interval from 292 K to 383 K. The contributions of ionic and electronic components into the total electrical conductivity were separated as well as their temperature behavior was studied. The dependences of ionic and electronic conductivity and their activation energies on average size of the crystallites in (Cu0.5Ag0.5)7SiS5I-based ceramic samples were investigated.

Electrical Conductivity in Praseodymium-Cerium Oxide

2002 ◽  
Vol 756 ◽  
Author(s):  
Todd S. Stefanik ◽  
Harry L. Tuller
Keyword(s):  
Electrical Conductivity ◽  
Ionic Conductivity ◽  
Cerium Oxide ◽  
Electronic Conductivity ◽  
Impurity Band ◽  
Defect Model ◽  
Valence States ◽  
Partial Pressures ◽  
Wide Range ◽  
Low Levels

ABSTRACTThe electrical conductivity of PrxCe1-xO2-δ (PCO) for 0 ≤ × ≤ 0.20 was examined over a wide range of temperatures and oxygen partial pressures. A defect model based on multiple Pr valence states was found to be qualitatively consistent with the observed data. A unique pO2-dependent ionic conductivity is observed at high pO2 values in compositions containing low levels of Pr (0 ≤ × ≤ 0.01). In compositions containing higher amounts of Pr (0.05 ≤ × ≤ 0.20), formation of a Pr induced impurity band results in a significant electronic conductivity at high pO2 values.

scholarly journals Structure and Electrical Properties of Superionic Ceramics Based on Silver-Enriched (Cu0.25Ag0.75)7SiS5I Solid Solution

2021 ◽  
Vol 66 (6) ◽  
pp. 489
Author(s):  
A.I. Pogodin ◽  
I.O. Shender ◽  
S.M. Bereznyuk ◽  
M.Y. Filep ◽  
O.P. Kokhan ◽  
...  
Keyword(s):  
Solid Solution ◽  
Electrical Conductivity ◽  
Microstructural Analysis ◽  
Structural Studies ◽  
Frequency Range ◽  
Impedance Measurements ◽  
Total Electrical Conductivity ◽  
Ceramic Samples ◽  
Electronic Conductivities ◽  
Temperature Dependences

(Cu0.25Ag0.75)7SiS5I-based superionic ceramics were fabricated by using the micro- and nanopowders. The XRD technique and microstructural analysis are applied for the structural studies of powders and ceramic samples. The impedance measurements of ceramic samples are carried out in the frequency range from 10Hz to 2 × 106 Hz and temperature interval from 292 K to 383 K. The contributions of ionic and electronic conductivities into the total electrical conductivity are determined, and their temperature dependences are investigated. The influence of the size effect on ionic and electronic conductivities and their activation energies in (Cu0.25Ag0.75)7SiS5I-based ceramics is studied.

scholarly journals Investigation of Ion and Electron Conduction in the Mixed Ionic-Electronic Conductor- La-Sr-Co-Fe-Oxide (LSCF) Using Alternating Current (AC) and Direct Current (DC) Techniques

2021 ◽  
Author(s):  
Chong Lei ◽  
Michael Simpson ◽  
Anil Virkar
Keyword(s):  
Ionic Conductivity ◽  
Electronic Conductivity ◽  
Electron Conduction ◽  
Oxygen Ion ◽  
Electronic Current ◽  
Mixed Ionic Electronic Conductor ◽  
Measurement Results ◽  
In Series ◽  
Mixed Ionic Electronic Conductors ◽  
Increasing Temperature

Abstract Among many mixed ionic electronic conductors (MIECs), lanthanum strontium cobalt iron oxide (LSCF) has been proven as a promising material for use as cathode in SOFCs. The ion and electron conduction in LSCF need to be studied separately. To measure the ionic conductivity of LSCF, YSZ disks were applied to block the electronic current, and multilayered samples were made with YSZ disks in series with an LSCF disk. Both AC and DC techniques were used for the measurements. An LSCF(porous)/LSCF(dense)/LSCF(porous) bar-shaped sample was made to measure the electronic conductivity of LSCF. DC technique was utilized for the measurement. Results show that the ionic conductivity of LSCF is much lower than its electronic conductivity. The ionic conductivity of LSCF increases with increasing temperature (600-900°C), and the electronic conductivity decreases with increasing temperature (600-900°C). Measurements were also made on a foil of silver to investigate oxygen transport through it. From this, oxygen ion conductivity through silver was estimated.

Revisiting the passivation of stainless steels and other passive CRAs

2018 ◽  
Vol 106 (1) ◽  
pp. 107 ◽  
Author(s):  
Jean- Louis Crolet
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Base Metal ◽  
Stainless Steels ◽  
Electronic Conductivity ◽  
Transport Processes ◽  
General Knowledge ◽  
Inorganic Polymers ◽  
Faraday Cage

All that was said so far about passivity and passivation was indeed based on electrochemical prejudgments, and all based on unverified postulates. However, due the authors’ fame and for lack of anything better, the great many contradictions were carefully ignored. However, when resuming from raw experimental facts and the present general knowledge, it now appears that passivation always begins by the precipitation of a metallic hydroxide gel. Therefore, all the protectiveness mechanisms already known for porous corrosion layers apply, so that this outstanding protectiveness is indeed governed by the chemistry of transport processes throughout the entrapped water. For Al type passivation, the base metal ions only have deep and complete electronic shells, which precludes any electronic conductivity. Then protectiveness can only arise from gel thickening and densification. For Fe type passivation, an incomplete shell of superficial 3d electrons allows an early metallic or semimetallic conductivity in the gel skeleton, at the onset of the very first perfectly ordered inorganic polymers (- MII-O-MIII-O-)n. Then all depends on the acquisition, maintenance or loss of a sufficient electrical conductivity in this Faraday cage. But for both types of passive layers, all the known features can be explained by the chemistry of transport processes, with neither exception nor contradiction.

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