scholarly journals Effect of Fe Substitution on the Structural, Electrical and Dielectric Properties of La0.70Ca0.30MnO3 Cathode for SOFCs

2019 ◽  
Vol 9 (1) ◽  
pp. 324-328
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Reaction Route ◽  
X Ray ◽  
Suitable Material ◽  
Density Values ◽  
Electrical And Dielectric Properties ◽  
Fe Substitution

Perovskite solid solutions (La0.70Ca0.30)(FexMn1-x)O3 where x = 0.01, 0.20, 0.30 and 0.40 ceramics were synthesized by solid state reaction route. The structural studies were carried by X-Ray diffraction method and the observed results have indicated that all the prepared samples were crystallized into single phase. The surface morphology was studied by Scanning Electron Microscopy and the images have revealed that grain size has increased with the increasing concentration of Fe. Archimedes principle was used to calculate the density of all the sintered samples and the density values were observed to be in increasing order. The impedance and dielectric properties have been characterized at different ranges of temperature and frequency. The value of electrical conductivity were found to be more than 100 S cm-1 , which indicate that the synthesized material is suitable material for cathode of Solid Oxide Fuel Cell.

scholarly journals Sintering behaviour and microwave dielectric properties of MgO-2B2O3-xwt%BaCu(B2O5)-ywt%H3BO3 ceramics

2021 ◽  
Author(s):  
Haiquan Wang ◽  
Shixuan Li ◽  
Kangguo Wang ◽  
Xiuli Chen ◽  
Huanfu Zhou
Keyword(s):  
Dielectric Properties ◽  
Bulk Density ◽  
Single Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
X Ray Diffraction ◽  
Microwave Dielectrics ◽  
X Ray ◽  
Microwave Dielectric ◽  
Sintering Behaviour

AbstractThis study investigates the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 series ceramics synthesised by solid-state reaction. According to the X-ray diffraction and microstructural analyses, the as-prepared MgO-2B2O3 ceramics possess a single-phase structure with a rod-like morphology. The effects of different quantities of H3BO3 and BaCu(B2O5) (BCB) on the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 ceramics were investigated. Accordingly, the optimal sintering temperature was obtained by adding 30 wt% H3BO3 and 8 wt% BCB. We also reduced the sintering temperature to 825 °C. Furthermore, the addition of 40 wt% H3BO3 and 4 wt% BCB increased the quality factor, permittivity, and temperature coefficient of resonance frequency of MgO-2B2O3 to 44,306 GHz (at 15 GHz), 5.1, and −32 ppm/°C, respectively. These properties make MgO-2B2O3 a viable low-temperature co-fired ceramic with broad applications in microwave dielectrics.

Preparation of Forsterite by Solid State Synthesis Process and its Dielectric Properties

2012 ◽  
Vol 534 ◽  
pp. 110-113 ◽  
Author(s):  
Fei Shi ◽  
Peng Cheng Du ◽  
Jing Xiao Liu ◽  
Ji Wei Wu ◽  
Chun Yuan Luo
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Single Phase ◽  
Raw Materials ◽  
Magnesium Carbonate ◽  
Solid State Synthesis ◽  
Molar Ratio ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
X Ray

Using basic magnesium carbonate (Mg(OH)2•4MgCO3•6H2O) and SiO2 as raw materials, forsterite (Mg2SiO4) was prepared by solid state synthesis process. The optimal process for synthesizing Mg2SiO4 was obtained by adjusting Mg/Si molar ratio and sintering temperature. The crystal phase of the obtained Mg2SiO4 powder was determined by X-ray diffraction (XRD). The results indicate that the single-phase Mg2SiO4 powder can be obtained when the mixtures with Mg/Si molar ratio of 2.05～2.01 were sintered at 1350°C for 3h in the air. The as-prepared Mg2SiO4 ceramic samples which were sintered at 1300～1360°C showed better dielectric properties with εr=7.4 and tanδ =7.5×10-4.

PREPARATION AND CHARACTERIZATION OF CIS POWDERS BY A FACILE REFLUXING REACTION ROUTE

2013 ◽  
Vol 12 (05) ◽  
pp. 1350031
Author(s):  
J. C. ZHOU ◽  
Y. Y. WANG ◽  
X. L. GONG ◽  
S. W. LI
Keyword(s):  
Single Phase ◽  
Stoichiometric Composition ◽  
Chalcopyrite Structure ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Reaction Route ◽  
X Ray ◽  
Structure Morphology ◽  
Short Time

CuInSe 2 (CIS)-based powders were successfully prepared by a facile refluxing reaction route using metal halides and Se / S powder as raw starting materials. The phase and crystallographic structure, morphology, chemical composition of the products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS). It is found that single phase CIS powders with chalcopyrite structure can be prepared in a relatively short time using triethylenetetramine as the solvent; the most suitable reaction temperature and time are 200°C, 1–2 h, respectively. CuIn ( S x Se 1-x)2 powders were also prepared by refluxing reaction route using the mixed solvent of triethylenetetramine–glycol (1:1, v/v). The characterizations showed that the CuIn ( S x Se 1-x)2 has single chalcopyrite phase, and the stoichiometric composition closely follows the primary mixed ratio. The morphology of CuIn ( S x Se 1-x)2 is close to spheres, and the particle sizes become distinctly smaller with the incorporation of S . A possible formation mechanism of CuInSe 2 was put forward and briefly discussed.

Phase Formation and Grain Growth of BSCZT Ceramics Prepared by BST-BZT Seed Induced Method

2018 ◽  
Vol 766 ◽  
pp. 175-179
Author(s):  
Jiraporn Dangsak ◽  
Sukum Eitssayeam ◽  
Denis Russell Sweatman ◽  
Uraiwan Intatha
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Phase Formation ◽  
Room Temperature ◽  
Single Phase ◽  
Seed Crystal ◽  
Lead Free ◽  
X Ray Diffraction ◽  
X Ray ◽  
Density Values

In this work, lead-free Ba0.4Sr0.4Ca0.2Zr0.05Ti0.95O3 ceramics were prepared by the seed induced method using (0.5Ba0.6Sr0.4TiO3–0.5BaZr0.05Ti0.95O3) (BST-BZT) seed. Seed crystals with concentrations of 0, 2.5, 5, 7.5, 10 mol% were mixed with BSCZT powder for 24 h and sintered at 1400 °C for 4 h. The phase formation and microstructure of BSCZT ceramic were characterized by X-ray diffraction technique (XRD) and the scanning electron microscopy (SEM). All samples showed a single phase perovskite structure without impurities and exhibited the existence of the tetragonal phase. The density values of the ceramics decreased from 4.90 to 4.75 g/cm3 with increasing seed crystal concentrations. The grain size of the sample without seed was 3.71 μm, whereas a grain size of 8.99 μm was observed for the sample with 10 mol% seed crystal. The dielectric constant at room temperature at 1 kHz was 1831 for the sample with 10 mol% seed crystal while the dielectric constant of the sample without seed was 1484. From the results in this work, BST-BZT seed can increase grain size and improve the dielectric constant at room temperature.

Influence of Sintering Temperature on Densification and Microstructure of Zn3Nb2O8 Ceramics Derived from Nanopowders

2011 ◽  
Vol 194-196 ◽  
pp. 656-659 ◽  
Author(s):  
Phakkhananan Pakawanit ◽  
Supon Ananta
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Sintering Temperature ◽  
Density Measurement ◽  
Maximum Density ◽  
Dielectric Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dielectric Ceramics ◽  
Scanning Electron

Zinc niobate, Zn3Nb2O8, dielectric ceramics were fabricated by sintering Zn3Nb2O8 nanopowders derived from a rapid vibro-milling technique at various temperatures. Phase formation, densification, microstructure and dielectric properties of the ceramics were investigated as a function of sintering temperatures (1000-1200°C), using a combination of X-ray diffraction, Archimedes density measurement, scanning electron microscopy and dielectric measurement, respectively. It has been found that single-phase Zn3Nb2O8 ceramics with maximum density of ~98% theoretical density can be successfully produced with appropriate firing temperature, without any firing additives. Moreover, it is seen that the dielectric properties are found to enhance with increasing sintering temperature and grain size.

scholarly journals Investigations on Structural, Mechanical, and Dielectric Properties of PVDF/Ceramic Composites

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Anshuman Srivastava ◽  
Karun Kumar Jana ◽  
Pralay Maiti ◽  
Devendra Kumar ◽  
Om Parkash
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Single Phase ◽  
Extrusion Process ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
Composite State ◽  
X Ray ◽  
Embedded Capacitor ◽  
Xrd Patterns

Polymer ceramic composites are widely used for embedded capacitor application. In the present work PVDF has been used as a matrix and CCTO and LaCCTO have been used as reinforcement. Extrusion process has been used for the synthesis of composites. X-ray diffraction (XRD) patterns confirm the formation of single phase CCTO, and LaCCTO in its pure as well as composite state. It is found that La doping in CCTO considerably increases the dielectric constant and reduces the dielectric loss. A similar trend is observed in the composites with the increasing content of CCTO and LaCCTO.

Effects of Manganese Addition on Phase Formation Behavior and Dielectric Properties of ((K0.5Na0.5)0.935Li0.065)NbO3 Ceramics

2014 ◽  
Vol 608 ◽  
pp. 206-211
Author(s):  
Supattra Wongsaenmai ◽  
Santi Maensiri ◽  
Rattikorn Yimnirun
Keyword(s):  
Dielectric Properties ◽  
Phase Formation ◽  
Single Phase ◽  
Structural Phase ◽  
Tetragonal Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Formation Behavior ◽  
Different Grain Size ◽  
Scanning Electron

In this study, ceramics in ((K0.5Na0.5)0.935Li0.065)NbO3+ xMnO2(mol%) ceramics (when x = 0.0025, 0.0050, 0.01 and 0.015) were successfully prepared by the conventional mixed-oxide technique. The structural phase formation and microstructure were characterized by x-ray diffraction technique (XRD) and scanning electron microscopy (SEM). The crystal structure was identified by XRD as a single-phase perovskite structure, with tetragonal symmetry. The microstructure shows different grain size with different composition x. This study clearly showed that the Mn has influence on the dielectric properties in ((K0.5Na0.5)0.935Li0.065)NbO3ceramics.

scholarly journals Structural, Dielectric and Electrical Properties of Fe Doped La0.7Ba0.3MnO3Solid Solutions for Cathode Materials

2019 ◽  
Vol 8 (3) ◽  
pp. 7313-7317
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray ◽  
Conventional Solid State Method ◽  
Density Values ◽  
State Method ◽  
Scanning Electron

The solid solutions of (La0.7Ba0.3)(FexMn1-x )O3 where x = 0.1 - 0.5 ceramics were synthesized by conventional solid-state method. The structural analysis was done by X-Ray diffraction technique and the results have revealed that all the samples were crystallized into a single phase. The surface morphology was done by Scanning Electron Microscopy and the micrographs clearly indicate decreased grain size with the increasing Fe - concentration. The density of the prepared samples was done using Archimedes principle and the density values were found to be in decreasing order, which is well in agreement with the microstructure relationship. The dielectric and impedance properties have been studied at different ranges of frequency and temperature. The electrical conductivity values were found to be greater than 100 Scm-1 , which suggests it to suitable cathode material of SOFCs

Enhanced Dielectric Properties of Sintered MgFe1.98Nd0.02O4 Nanoparticles

2020 ◽  
Vol 42 (1) ◽  
pp. 87-87
Author(s):  
U Rafiq U Rafiq ◽  
M Hanif M Hanif ◽  
M Anis ur Rehman and A Ul Haq M Anis ur Rehman and A Ul Haq
Keyword(s):  
Dielectric Properties ◽  
Loss Factor ◽  
Room Temperature ◽  
Grain Shape ◽  
Sol Gel ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Phase Purity ◽  
X Ray ◽  
Scanning Electron

Spinal MgFe1.98Nd0.02O4 was prepared by simplified sol-gel method. To measure the dielectric properties samples were sintered from 700-800 oC in the steps of 50 oC. The sample’s phase purity, crystallographic phase and crystallite size was measured by X-ray diffraction method (XRD). The pellets were analyzed in Scanning Electron Microscope for their surface morphology and grain shape. Dielectric properties were measured from 20 Hz to 3 MHz at room temperature. Samples sintered at 750 oC, showed highest value of AC conductivity which indicated that the material is suitable for use in sensors. However, minimum value of dielectric loss factor was obtained at 800 and#176;C which makes it more suitable for antenna applications.

Dielectric Properties of Ba1-xLaxTi1-x/4O3 Ceramics with Different La3+ Content

2012 ◽  
Vol 77 ◽  
pp. 35-40 ◽  
Author(s):  
Beata Wodecka-Dus ◽  
Malgorzata Adamczyk ◽  
Katarzyna Osinska ◽  
Malgorzata Plonska ◽  
Dionizy Czekaj
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Dielectric Properties ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composition Formula ◽  
Lcr Meter ◽  
Sintering Method ◽  
Agilent E4980a

Subscript textIn the present research n-doped BaTiO3 compositions, with lanthanum contents x=0, 0.1, 0.3 and 0.5mol% were prepared by the free sintering method, at temperature T=1350°C for 2 h. The EDS investigations showed that samples exhibited conservation of stoichiometry according to the chemical composition formula. Morphology of the ceramic material was observed by scanning electron microscopy, whereas the crystalline structure was studied by X-ray diffraction method. Influence of La3+ doping on dielectric properties of Ba1-xLaxTi1-x/4O3 ceramics was studied in temperature range T=20-260°C, and frequency f=100Hz-1000Hz by the Precision LCR meter Agilent E4980A. The results show a decrease of Tm with lanthanum addition. The degree of diffuseness of phase transition is more pronounced for high La content, implying the existence of a composition-induced phase transition of the ceramics. Ceramics showed maximally enhanced dielectric permittivity around phase transitions, which are the phase transitions of the pure BaTiO3.

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