AC electrical conduction mechanisms and dielectrical studies of DD3 kaolin sintered at high temperature

Khorchani, Ibrahim; Hafef, Olfa; Reinosa, J.J.; Matoussi, Adel; Fernández, J.F.

doi:10.1016/j.matchemphys.2018.03.053

Cited by 9 publications

(4 citation statements)

References 48 publications

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“…Sample A presented the cristobalite phase when fired at 1400 °C and with the temperature increase it was observed that this phase disappeared, while the α-alumina was considerably reduced. For samples B and D that presented lower alumina content in its composition (Table I), when sintered at the temperature range studied, it was identified only the crystalline phase of mullite and vitreous phase; similar behavior was observed by other researchers [22]. For sample C, it was observed the presence of the alumina phase up to 1450 °C, which disappeared with the increase of firing temperature up to 1500 °C, thus increasing the amount of mullite.…”

Section: Resultssupporting

confidence: 83%

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

et al. 2020

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The aim was to study formulations containing aluminosilicate and alumina in order to obtain compositions with suitable properties to fabricate dielectric ceramic devices. Initially, the precursors were subjected to chemical, mineralogical and granulometric characterization. The formulations were defined and specimens were pressed (19.6 MPa) in shapes of disc and rectangular bar. Specimens were dried, heat-treated at 1400, 1450 and 1500 °C and the mineralogical, morphological, physical, dielectric and mechanical properties were evaluated. The relative dielectric constant (εr) and loss tangent (tanδ) were evaluated at 0.1, 1, 10 and 100 kHz at room temperature. The mullite was the major phase for the studied temperature range. Compositions with a higher content of fluxes showed lower porosity and better dielectric properties and flexural strength. Values of εr at 1 kHz (~3.5 to 4.5) were close to that of the mullite for the samples fired at 1400 °C.

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Section: Resultssupporting

confidence: 83%

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

et al. 2020

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“…Cristobalite beta (tetragonal silica, JCPDS 89-3435), commonly expected at 2θ ~22° in kaolin processed ceramics, was not identified within the detection limit of the XRD technique. The formation of an additional glassy phase (amorphous phase, herein assigned as cristobalite phase, JCPDS 82-0512) was observed by the occurrence of a large band in the region between 15-30° 2θ, expected for metakaolinderived mullite [22]. Quantitative Rietveld phase analysis indicated the crystalline fraction of the mullite/glass composite was composed of 47.6 wt% mullite and residual quartz (2.3 wt%).…”

Section: Resultsmentioning

confidence: 99%

Dielectric and electrical properties of a mullite/glass composite from a kaolinite clay/mica-rich kaolin waste mixture

et al. 2019

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A mullite/glass composite has been prepared by reactive sintering of a kaolinite clay/mica-rich kaolin waste mixture with 25 wt% waste. Phase composition, microstructure, dielectric and electrical properties of the composite fired at 1400 °C were evaluated by X-ray diffraction, scanning electron microscopy and impedance spectroscopy (between 25 and 600 °C in air). The microstructural characterization showed the attainment of dense samples composed of acicular (orthorhombic) mullite (47.6 wt%), glassy phase (50.1 wt%), and residual quartz (2.3 wt%). Electrical conductivity (1.9x10 -8 S/cm at 300 °C), dielectric constant (6.7 at 1 MHz, 25 °C) and dielectric loss (0.024 at 1 MHz, 25 °C) results gave evidence that the mullite/glass composite is a promising low-cost material for commercial use in electronics-related applications.

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“…As shown in Figure 3a, the strong peaks at 2917 and 2860 cm −1 in the spectra of the PA are the asymmetric and symmetric vibration of -CH 3 and -CH 2 group, while the band at 1702 cm −1 stands for the C=O stretching vibration, the peak at 1071 cm −1 signifies the C-O stretching vibration [28]. The wide peak between 1000 and 1200 cm −1 in the spectra of mullite may be ascribed to the Al-O and Si-O stretch vibration [32]. As shown in Figure 3a, all the characteristic peaks of PA and mullite appear and no new peaks emerge in the FTIR spectra PA/mullite FSPCM.…”

Section: Chemical Compatibility Of the Pa/mullite Fspcmmentioning

confidence: 97%

Mullite Stabilized Palmitic Acid as Phase Change Materials for Thermal Energy Storage

Liu

Bian

et al. 2018

Minerals

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In this paper, mullite was adopted in order to absorb Palmitic Acid (PA) via a direct impregnation method. The prepared PA/mullite form-stable phase change materials (FSPCM) were systematically characterized by the Leakage Test (LT), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Differential Scanning Calorimeter (DSC), Thermogravimetry (TG) and Cooling Curve Method (CCM). The results indicated that, among these composites with different mass fractions of PA, the sample with the 32 wt % Palmitic Acid has the best properties without any leakage. The enthalpy of 32%PA/68%mullite FSPCM is 50.8 J/g for melting process, and 58.3 J/g for solidifying process. The phase change point of 32%PA/68%mullite FSPCM is 64.1 °C for melting and 58.7 °C for solidifying. The heat storage efficiency of the PA/mullite FSPCM was enhanced considerably by adding mullite. The leakage and thermal properties of PA/mullite FSPCM were discussed and the performance of the FSPCM has been apparently improved.

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AC electrical conduction mechanisms and dielectrical studies of DD3 kaolin sintered at high temperature

Cited by 9 publications

References 48 publications

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

Dielectric and electrical properties of a mullite/glass composite from a kaolinite clay/mica-rich kaolin waste mixture

Mullite Stabilized Palmitic Acid as Phase Change Materials for Thermal Energy Storage

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