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

Grilo, João P.F.; Alves, Hugo P.A.; Araújo, Allan J.M.; Andrade, Rivaildo M.; Dutra, Ricardo Peixoto Suassuna; Macedo, Daniel A.

doi:10.1590/0366-69132019653732648

Cited by 13 publications

(5 citation statements)

References 12 publications

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“…According to the literature [28], mullite presents a dielectric constant in the range of 6 to 7 at the frequency of 1 kHz. The analysis of the loss tangent (tanδ) evidenced a tendency of reduction with the increase in frequency, behavior also observed by other researchers [5]. For samples A, B and C, making an analysis of the loss tangent for the frequencies above 0.1 kHz, it was observed that the smallest values were found for the samples sintered at 1450 and 1500 °C.…”

Section: Resultssupporting

confidence: 83%

“…For the substrate made with these materials, a signal delay can be diminished in very high-frequency communication systems [3]. Among the ceramic materials, mullite and mullite-based composites are highlighted in the electronic industry due to their low values of dielectric constant and loss tangent, as well as low coefficient of thermal expansion, being applied as electronic substrate, microelectronic packaging, electrical insulators and ceramic capacitors [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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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%

Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

et al. 2020

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“…Such a behavior can be explained based on the dynamic motion of dipoles and the relaxation of dipoles with the rise in frequency may result in this type of characteristic feature. [22] However, the permittivity spectrum of the Y 2 O 3 -PMZ composite does not exhibit this type of anomaly. Here, any dipolar relaxation has not been observed in the experimental temperature range.…”

Section: Temperature-dependent Dielectric Propertiesmentioning

confidence: 99%

AC Conduction Mechanism and Impedance Analysis of Conventional and Plasma‐Sintered Yttria‐Stabilized ZrO₂@Mullite Composite

Biswal,

Mishra

2023

Cryst. Res. Technol.

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The addition of 8 mol% of Y2O3 to the ZrO2@mullite composites stabilizes the metastable tetragonal phase of ZrO2 in conventional and plasma‐sintered Y2O3‐stabilized ZrO2@mullite composites. A fused, highly dense, and interconnected microstructure is formed in the case of plasma‐sintered Y2O3 stabilized ZrO2@mullite composite. At 1 MHz frequency, the room temperature and tanδ of (10.37 and 2.06) is obtained for the conventional Y2O3 stabilized ZrO2@mullite composite and that of (38.8 and 4.02) is observed for the plasma sintered Y2O3 stabilized ZrO2@mullite composite. The substitution of Y3+ in place of Zr4+ creates sufficiently large oxygen vacancies at the grain boundary regions of these composites endowed mostly with the ZrO2 phase. In conventional Y2O3‐ ZrO2@mullite composites, both dielectric relaxation as well as conductivity relaxation are observed due to the dynamic motion of dipoles and relaxation due to the presence of defect states and porous structures. This leads to higher grain boundary conductivity than the grain conductivity of these composites. Thermally activated conduction mechanisms exhibited in these composite materials are projected from the complex impedance and modulus analysis. The conventional and plasma sintered Y2O3‐ ZrO2@mullite composite has an optical bandgap of 3.26 and 3.58 eV, respectively.

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“…At present, some studies only focus on the alternative methods of resource utilization of these wastes in the resource utilization of WDC, such as the production of building materials, such as bricks (George and Antonis 2021 ; Mojtaba et al 2020 ; Symeonides et al 2019 ; Ayati et al 2019 ; Dai et al 2019 ), concrete (Yang et al 2021 ; Mohsen et al 2021 ; Li et al 2020a , b ; Amelung al. 2020 ; Ma et al 2019 ), aggregates (Bamdad et al 2019 ; Siddique et al 2021 ; Sundis et al 2021 ; Moreno-Maroto et al 2018 ; Prachasaree et al 2020 ), glass materials (Baino and Ferraris 2019 ; Stoch et al 2018 ; Grilo et al 2019 ; Alves et al 2017 ), slag-red mud cementitious materials (Ban et al 2018 ; Faried et al 2021 ; Mymrin et al 2017 ; Ye et al 2017 ), and ceramic materials (Sun et al 2021 ; Cheng et al 2018 ; Ren et al 2019 ; Cao et al 2019 ).…”

Section: Introductionmentioning

confidence: 99%

Human carcinogenic risk analysis and utilization of shale gas water-based drilling cuttings in road materials

Wang

Chen

Huang³

et al. 2022

Environ Sci Pollut Res

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Water-based drilling cuttings (WDC) generated during shale gas development will endanger human health and ecological security. The modern analytical techniques are used to analyze the organic pollutants in WDC, and the human health and ecological security risks of harmful pollutants in WDC under specific scenarios are evaluated. The results showed that the content of organic pollutants in WDC was evaluated by human health and safety risk assessment. The comprehensive carcinogenic risks of all exposure pathways of single pollutant benzo(a)anthracene, benzo(a)pyrene, benzo(k)fluoranthene, and indeno(1,2,3-cd)pyrene were acceptable. However, the cumulative carcinogenic risk of exposure to dibenzo(a,h)anthracene particles via skin exposure was not acceptable. It was considered that only dibenzo(a,h)anthracene had carcinogenic effect, and the risk control limit of dibenzo(a,h)anthracene in WDC was 1.8700 mg/kg by calculation. As well as, the “WDC-cement” gel composite structure was deeply analyzed, and the physical and chemical properties and mechanism of organic pollutants in cement solidified WDC were analyzed, which provided theoretical support for the study of WDC pavement cushion formula. Based on the above conclusions and combined with the actual site, by studying and adjusting the formula of WDC pavement cushion, the WDC pavement cushion was finally designed by 6% cement + 50% WDC + 44% crushed stone. The 7d unconfined compressive strength met the requirements of the Chinese standard “ Technical Guidelines for Construction of Highway Roadbases ” (JTG/T F20-2015). Also, the process route of WDC as road cushion product was sampled and analyzed. In addition, the leaching concentration of main pollutants all met the relevant standards of China. Therefore, this study can provide a favorable way for the efficient, safe, and environmentally friendly utilization of WDC, and ensure the ecological environment safety and human health safety of WDC in resource utilization.

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

Cited by 13 publications

References 12 publications

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

AC Conduction Mechanism and Impedance Analysis of Conventional and Plasma‐Sintered Yttria‐Stabilized ZrO₂@Mullite Composite

Human carcinogenic risk analysis and utilization of shale gas water-based drilling cuttings in road materials

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

Cited by 13 publications

References 12 publications

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

AC Conduction Mechanism and Impedance Analysis of Conventional and Plasma‐Sintered Yttria‐Stabilized ZrO2@Mullite Composite

Human carcinogenic risk analysis and utilization of shale gas water-based drilling cuttings in road materials

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AC Conduction Mechanism and Impedance Analysis of Conventional and Plasma‐Sintered Yttria‐Stabilized ZrO₂@Mullite Composite