scholarly journals Influence of ZnO addition on microstructure and proton electrical conductivity of BaZr0.8Y0.2O3-δ ceramics

2021 ◽  
Vol 15 (2) ◽  
pp. 202-209
Author(s):  
Leonardo Wendler ◽  
Kethlinn Ramos ◽  
Dulcina Souza
Keyword(s):  
Electrical Conductivity ◽  
Grain Boundaries ◽  
Barium Zirconate ◽  
Protonic Conductivity ◽  
Vitreous Phase ◽  
Microstructure Development ◽  
Conductivity Measurements ◽  
Sintering Aids ◽  
Oxide Mixture ◽  
Sintering Aid

Sintering aids are widely used to promote densification and grain growth for electrolytes based on yttriumdoped barium zirconate. However, there are some discrepancies in the literature about the influence of these sintering aids on the microstructure development. Some authors consider that ZnO remains on grain boundaries, forming an amorphous phase that promotes sintering, and others proposed that ZnO forms a solid solution with barium zirconate. Even considering different mechanisms, it was proposed that ZnO addition compromised protonic conductivity. In this work BaZr0.8Y0.2O3-? (BZY20) was prepared by conventional oxide mixture (solid state sintering), adding ZnO as sintering aid. We proposed a mechanism for the ZnO actuation on the microstructure development, by the formation of a liquid phase during sintering and formation of a vitreous phase throughout grain boundaries during cooling. This could be the reason for poor protonic conductivity in comparison to the undoped BZY20 electrolytes. The proposed mechanism was established through the scanning electron microscopy analyses and electrical conductivity measurements under several different atmospheres by impedance spectroscopy. High density samples were obtained by using ZnO, but with compromised electrical conductivity compared to the undoped samples.

Preparation and Electrical-Conductive Property of SnO2-Based Ceramics with 0.5% CuO and Sb2O3

2007 ◽  
Vol 352 ◽  
pp. 263-266 ◽  
Author(s):  
Lian Meng Zhang ◽  
Guo Qiang Luo ◽  
J. Li ◽  
Dong Ming Zhang ◽  
Qiang Shen
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Probe Method ◽  
Pressureless Sintering ◽  
Densification Behavior ◽  
Microstructure Development ◽  
Sintering Aid ◽  
Wide Range ◽  
Electrical Resistivities ◽  
Conductive Property

In this study, SnO2-based ceramics, with 0.5%CuO as sintering aid and Sb2O3 as activator of the electrical conductivity, was obtained by pressureless sintering at 1450°C for 5 h. Densification behavior and microstructure development strongly depend on Sb2O3. The characteristization of microstructures on Sb2O3 concentrations are analyzed by SEM. A small amount of CuO improves densification; Sb2O3 retards the densification of SnO2-based ceramic. The electrical resistivities of SnO2-based ceramics with different contents of Sb2O3 are measured by the standard four probe method and varied in a wide range. The electrical resistivity arrives the minimal value of 4.964×10-2 0·cm for 99%SnO2+0.5%CuO +0.5%Sb2O3. More content of Sb2O3 than that of CuO causes the degression of density and the increasing of electrical resistivity of ceramics.

Total Body Electrical Conductivity Measurements in the Neonate

1991 ◽  
Vol 18 (3) ◽  
pp. 611-627 ◽  
Author(s):  
Marta L. Fiorotto ◽  
William J. Klish
Keyword(s):  
Electrical Conductivity ◽  
Conductivity Measurements ◽  
Total Body

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.

Structure and Conductivity of Iodine-Doped C60 Thin Films

1994 ◽  
Vol 359 ◽  
Author(s):  
Jun Chen ◽  
Haiyan Zhang ◽  
Baoqiong Chen ◽  
Shaoqi Peng ◽  
Ning Ke ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Room Temperature ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
X Ray ◽  
Thermally Activated ◽  
Order Of Magnitude

ABSTRACTWe report here the results of our study on the properties of iodine-doped C60 thin films by IR and optical absorption, X-ray diffraction, and electrical conductivity measurements. The results show that there is no apparent structural change in the iodine-doped samples at room temperature in comparison with that of the undoped films. However, in the electrical conductivity measurements, an increase of more that one order of magnitude in the room temperature conductivity has been observed in the iodine-doped samples. In addition, while the conductivity of the undoped films shows thermally activated temperature dependence, the conductivity of the iodine-doped films was found to be constant over a fairly wide temperature range (from 20°C to 70°C) exhibiting a metallic feature.

Synthesis of New Chalcogenide Materials. The Novel One-Dimensional Semiconductor K4 Ti3 S14

1987 ◽  
Vol 97 ◽  
Author(s):  
Steven A. Sunshine ◽  
Doris Kang ◽  
James A. Ibers
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Alkali Metal ◽  
The Novel ◽  
Conductivity Measurements ◽  
One Dimensional ◽  
General Utility ◽  
Solid State Materials ◽  
Chalcogenide Materials

ABSTRACTThe use of A2 Q/Q melts (A - alkali metal, Q - S or Se) for the synthesis of new one-dimensional solid-state materials is found to be of general utility and is illustrated here for the synthesis of K4 Ti3 SI4. Reaction of Ti metal with a K2 S/S melt at 375°C for 50 h affords K4 Ti3 SI4. The structure possesses one-dimensional chains of seven and eightcoordinate Ti atoms with each chain isolated from all others by surrounding K atoms. There are six S-S pairs (dave - 2.069(3) Å) so that the compound is one of TiIV and may be described as K4 [Ti3 (S)2 (S2)6]. Electrical conductivity measurements indicate that this material is a semiconductor.

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