scholarly journals Synthesis by Hydrothermal Treatment of ZnO-Based Varistors Doped with Rare Earth Oxides and Their Characterization by Impedance Spectroscopy

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1134
Author(s):  
J. Porcayo-Calderon ◽  
J.J. Ramos-Hernandez ◽  
C.D. Arrieta-Gonzalez ◽  
J.G. Chacon-Nava ◽  
J.G. Gonzalez-Rodriguez ◽  
...  
Keyword(s):  
Rare Earth ◽  
Impedance Spectroscopy ◽  
Hydrothermal Treatment ◽  
Rare Earth Oxide ◽  
Rare Earth Oxides ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrical And Dielectric Properties ◽  
Ceramic Varistor

ZnO-based ceramic varistors have shown excellent electrical and dielectric properties due to their characteristics microstructures represented by the arrangement of their grains and grain boundaries that allow the absorption and flow of energy when subjected to an electrical surge. Their properties and characteristics depend on their chemical compositions and processing routes. Typical processing routes involve several stages of grinding and precalcination—which are time consuming processes. Because of this, this study proposes a simpler and cheaper alternative route for processing ceramic varistors. The alternative process proposed is the mixing of the precursor oxides by means of a hydrothermal treatment. The characteristics and properties of the synthesized ceramic varistors were evaluated by means of scanning electron microscopy, X-ray diffraction and impedance spectroscopy, considering the effect of the addition of rare earth oxides (La2O3, CeO2 and Nd2O3). The results showed that the mixing of the oxides through hydrothermal treatment produces ceramic varistors with characteristics and properties similar to those obtained by other processing routes. Furthermore, it was observed that the addition of rare earth oxides affects the characteristics and properties of the ceramic varistor depending on the type of rare earth oxide added, its concentration and ionic radius.

scholarly journals Effect of Rare Earth Oxides on Microstructure and Corrosion Behavior of Laser-Cladding Coating on 316L Stainless Steel

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 636 ◽  
Author(s):  
Xu ◽  
Wang ◽  
Chen ◽  
Qiao ◽  
Zhang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Rare Earth ◽  
Corrosion Behavior ◽  
Laser Cladding ◽  
316L Stainless Steel ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Rare Earth Oxides ◽  
X Ray Diffraction ◽  
X Ray

The effect of rare earth oxides on the microstructure and corrosion behavior of laser-cladding coating on 316L stainless steel was investigated using hardness measurements, a polarization curve, electrochemical impedance spectroscopy (EIS), a salt spray test, X-ray diffraction, optical microscopy, and scanning electron microscopy (SEM). The results showed that the modification of rare earth oxides on the laser-cladding layer caused minor changes to its composition but refined the grains, leading to an increase in hardness. Electrochemical and salt spray studies indicated that the corrosion resistance of the 316L stainless steel could be improved by laser cladding, especially when rare earth oxides (i.e., CeO2 and La2O3) were added as a modifier.

Structural analysis of excess-anion C-type rare earth oxide: a case study with Gd1−xCexO1.5+x/2(x= 0.20 and 0.40)

2003 ◽  
Vol 36 (4) ◽  
pp. 1082-1084 ◽  
Author(s):  
V. Grover ◽  
S. N. Achary ◽  
A. K. Tyagi
Keyword(s):  
Rare Earth ◽  
Structural Analysis ◽  
Metal Ion ◽  
Rare Earth Oxide ◽  
Charge Balance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Lattice Space

Structural analysis of anion-rich C-type Gd2O3was carried by the Rietveld refinement of the powder X-ray diffraction data for compositions Gd0.8Ce0.2O1.60and Gd0.6Ce0.4O1.70. Both compounds have a body-centred cubic lattice (space groupIa\bar{3}, No. 206,Z= 32) with unit-cell parameters of 10.8488 (1) and 10.8542 (1) Å, respectively. Both of these compounds are iso-structural with the C-type rare earth oxides, with excess anions as required for charge balance. The structural analysis reveals that there are two different kinds of metal ion site, namely 8b(M1) and 24d(M2), and two different kinds of anion sites, namely 48e(O1) and 16c(O2). The excess anions occupy the 16c(xxx) sites. The two metal ions each form an approximately eightfold-coordination polyhedron with O1 and O2. The details of these two compositions are explained and compared with both the CeO2structure and the Gd2O3structure,i.e.the end member.

scholarly journals Rare-Earth Oxides as Alternative High-Energy Photon Protective Fillers in HDPE Composites: Theoretical Aspects

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1930
Author(s):  
Kiadtisak Saenboonruang ◽  
Worawat Poltabtim ◽  
Arkarapol Thumwong ◽  
Theerasarn Pianpanit ◽  
Chanis Rattanapongs
Keyword(s):  
Rare Earth ◽  
Attenuation Coefficient ◽  
Rare Earth Oxide ◽  
High Energy ◽  
Rare Earth Oxides ◽  
Lead Free ◽  
High Energy Photon ◽  
Energy Photon ◽  
X Ray ◽  
Shielding Properties

This work theoretically determined the high-energy photon shielding properties of high-density polyethylene (HDPE) composites containing rare-earth oxides, namely samarium oxide (Sm2O3), europium oxide (Eu2O3), and gadolinium oxide (Gd2O3), for potential use as lead-free X-ray-shielding and gamma-shielding materials using the XCOM software package. The considered properties were the mass attenuation coefficient (µm), linear attenuation coefficient (µ), half value layer (HVL), and lead equivalence (Pbeq) that were investigated at varying photon energies (0.001–5 MeV) and filler contents (0–60 wt.%). The results were in good agreement (less than 2% differences) with other available programs (Phy-X/PSD) and Monte Carlo particle transport simulation code, namely PHITS, which showed that the overall high-energy photon shielding abilities of the composites considerably increased with increasing rare-earth oxide contents but reduced with increasing photon energies. In particular, the Gd2O3/HDPE composites had the highest µm values at photon energies of 0.1, 0.5, and 5 MeV, due to having the highest atomic number (Z). Furthermore, the Pbeq determination of the composites within the X-ray energy ranges indicated that the 10 mm thick samples with filler contents of 40 wt.% and 50 wt.% had Pbeq values greater than the minimum requirements for shielding materials used in general diagnostic X-ray rooms and computerized tomography rooms, which required Pbeq values of at least 1.0 and 1.5 mmPb, respectively. In addition, the comparisons of µm, µ, and HVL among the rare-earth oxide/HDPE composites investigated in this work and other lead-free X-ray shielding composites revealed that the materials developed in this work exhibited comparable X-ray shielding properties in comparison with that of the latter, implying great potential to be used as effective X-ray shielding materials in actual applications.

Preparation of Ceria from Bastnaesite with NaHCO3 as Fluoride Retention Additive

2013 ◽  
Vol 477-478 ◽  
pp. 1423-1427
Author(s):  
Hui Zhong ◽  
Ke Hui Qiu ◽  
Yu Chong Qiu ◽  
Yu Tao Li ◽  
Ning Jia Fu
Keyword(s):  
Rare Earth ◽  
Hydrochloric Acid ◽  
Sodium Bicarbonate ◽  
Rare Earth Element ◽  
Earth Element ◽  
Rare Earth Oxide ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Elements

The CeO2 is prepared directly from bastnaesite as raw material that originated in Dechang, Sichuan province, China. Fully mixed with sodium bicarbonate (NaHCO3) and roasted at 550 °C, the rare earth element (REE) in bastnaesite transformed into rare earth oxide. And the CeO2 will be obtained by removing NaF through water washing and leaching the impurity elements including La, Fe, Al, Ca, etc. via hydrochloric acid (HCl). The CeO2 was characterized by X-ray diffraction (XRD) and X-ray fluorescence (XRF). The XRF results demonstrated that the content of CeO2 could reach more than 70% in products which can be used as polishing material.

Facile Systhesis La-Doped Nanoceria and Loaded Silver Nanoparticles Scavenging Hydroxyl Radicals

2014 ◽  
Vol 933 ◽  
pp. 23-26
Author(s):  
Kun Jie Wang ◽  
Ming Liang Li ◽  
Feng Guan ◽  
Hong Xia Li ◽  
Yan Ping Wu
Keyword(s):  
Silver Nanoparticles ◽  
Rare Earth ◽  
High Resolution ◽  
Hydroxyl Radicals ◽  
Energy Dispersive Spectrometer ◽  
Rare Earth Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
La Doped

In this work, we well performed the silver nanoparticles (AgNPs) supported on rare earth oxides ,which La-doped nanoceria nanocomposites for the scavenging Hydroxyl radicals that used facile and readily synthesized strategy .The complex microstructure nanoparticles were characterized by High resolution transmission electron microsopy (HRTEM), Energy dispersive spectrometer (EDS), X-ray diffraction (XRD). This paper showed AgNPs were immobilized on an functionalized dual-rare earth oxides surface that have a potential in biomedicine like antioxidant, anti-inflammatory, antibacterial and anticancer on perspectives future.

scholarly journals Study of the influence of 2.5% Mg2+ insertion in the B-site of La0.8Ca0.1Pb0.1FeO3 on its structural, electrical and dielectric properties

RSC Advances ◽  
2021 ◽  
Vol 11 (52) ◽  
pp. 33070-33080
Author(s):  
H. Issaoui ◽  
A. Benali ◽  
F. Issaoui ◽  
E. Dhahri ◽  
B. F. O. Costa ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Impedance Spectroscopy ◽  
Physical Properties ◽  
Complex Impedance ◽  
Experimental Techniques ◽  
Complex Impedance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrical And Dielectric Properties

This work involves the synthesis and study of physical properties of the La0.8Ca0.1Pb0.1Fe0.975Mg0.025O3 compound, which has been characterized by various experimental techniques, such as X-ray diffraction, SEM and complex impedance spectroscopy.

scholarly journals New Insights into the Crystal Chemistry of Elpidite, Na2Zr[Si6O15]·3H2O and (Na1+YCax□1−X−Y)Σ=2Zr[Si6O15]·(3−X)H2O, and Ab Initio Modeling of IR Spectra

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2160
Author(s):  
Alexander Bogdanov ◽  
Ekaterina Kaneva ◽  
Roman Shendrik
Keyword(s):  
Ir Spectra ◽  
Structural Models ◽  
Chemical Characterization ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Special Group ◽  
X Ray ◽  
Influence Of Water ◽  
Radioactive Species

Elpidite belongs to a special group of microporous zirconosilicates, which are of great interest due to their capability to uptake various molecules and ions, e.g., some radioactive species, in their structural voids. The results of a combined electron probe microanalysis and single-crystal X-ray diffraction study of the crystals of elpidite from Burpala (Russia) and Khan-Bogdo (Mongolia) deposits are reported. Some differences in the chemical compositions are observed and substitution at several structural positions within the structure of the compounds are noted. Based on the obtained results, a detailed crystal–chemical characterization of the elpidites under study was carried out. Three different structure models of elpidite were simulated: Na2ZrSi6O15·3H2O (related to the structure of Russian elpidite), partly Ca-replaced Na1.5Ca0.25ZrSi6O15·2.75H2O (close to elpidite from Mongolia), and a hypothetical CaZrSi6O15·2H2O. The vibration spectra of the models were obtained and compared with the experimental one, taken from the literature. The strong influence of water molecule vibrations on the shape of IR spectra of studied structural models of elpidite is discussed in the paper.

scholarly journals High Pressure X-ray Diffraction as a Tool for Designing Doped Ceria Thin Films Electrolytes

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 724
Author(s):  
Sara Massardo ◽  
Alessandro Cingolani ◽  
Cristina Artini
Keyword(s):  
Thin Films ◽  
High Pressure ◽  
Rare Earth ◽  
Ionic Conductivity ◽  
Bulk Material ◽  
Threshold Temperature ◽  
Doped Ceria ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rare Earth Doped

Rare earth-doped ceria thin films are currently thoroughly studied to be used in miniaturized solid oxide cells, memristive devices and gas sensors. The employment in such different application fields derives from the most remarkable property of this material, namely ionic conductivity, occurring through the mobility of oxygen ions above a certain threshold temperature. This feature is in turn limited by the association of defects, which hinders the movement of ions through the lattice. In addition to these issues, ionic conductivity in thin films is dominated by the presence of the film/substrate interface, where a strain can arise as a consequence of lattice mismatch. A tensile strain, in particular, when not released through the occurrence of dislocations, enhances ionic conduction through the reduction of activation energy. Within this complex framework, high pressure X-ray diffraction investigations performed on the bulk material are of great help in estimating the bulk modulus of the material, and hence its compressibility, namely its tolerance toward the application of a compressive/tensile stress. In this review, an overview is given about the correlation between structure and transport properties in rare earth-doped ceria films, and the role of high pressure X-ray diffraction studies in the selection of the most proper compositions for the design of thin films.

scholarly journals High-pressure synthesis of REB5O8(OH)2 (RE = Ho, Er, Tm)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Michael Zoller ◽  
Hubert Huppertz
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Ir Spectroscopy ◽  
Earth Metal ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Solution ◽  
Pressure Synthesis ◽  
The Rare Earth

AbstractThe rare earth oxoborates REB5O8(OH)2 (RE = Ho, Er, Tm) were synthesized in a Walker-type multianvil apparatus at a pressure of 2.5 GPa and a temperature of 673 K. Single-crystal X-ray diffraction data provided the basis for the structure solution and refinement. The compounds crystallize in the monoclinic space group C2 (no. 5) and are composed of a layer-like structure containing dreier and sechser rings of corner sharing [BO4]5− tetrahedra. The rare earth metal cations are coordinated between two adjacent sechser rings. Further characterization was performed utilizing IR spectroscopy.

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