Evaluation of electrical properties of glass-ceramics obtained from mill scale

Montedo, Oscar Rubem Klegues; Alves, Indiara Tereza; Faller, Cristian Arnaldo; Bertan, Fernando Marco; Piva, D.H.; Piva, Roger Honorato

doi:10.1016/j.materresbull.2015.07.040

Cited by 16 publications

(11 citation statements)

References 49 publications

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“…The type, content, size, and density of the crystal phases are the determining factors. The density of these glass-ceramics was in the range of ~1.8-3.0 g/cm 3 [25,26,[28][29][30][31]. Moreover, the glass-ceramics prepared in this work contain relatively small amounts of alkali metal and alkali earth metal cations (i.e.…”

Section: Resultsmentioning

confidence: 99%

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High strength glass-ceramics sintered with coal gangue аs а raw material

Dang

2019

Sci Sintering

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High strength lightweight glass-ceramics were fabricated with coal gangue and clay as main raw materials. The utilization ratio of coal gangue, the ratio of the coal gangue with clay, mineralization agents, forming process and sintering process on the properties of the fabricated glass-ceramics were optimized. The utilization ratio of coal gangue reached 75, and the ratio of coal gangue to clay was 3/1, as an optimal property was observed. The optimal sintering temperature was found to be 1370 o C. At this optimal temperature, the sintered glass-ceramics showed the main phase of mullite and spindle and so showed high strength, low density, and low water absorbance. The appropriate amounts of codoping of the TiO 2 , ZnO, and MnO 2 /dolomite as mineralization agents obviously enhanced the properties of the glass-ceramics. Process optimizations further determined reasonable and optimal process parameters. The high strength lightweight glass-ceramics fabricated in this work may be very suitable for various applications including building materials, cooking ceramics, and proppant materials, et al.

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Section: Resultsmentioning

confidence: 99%

“…Glass-ceramics are attractive materials used in various applications such as building materials, cooking ceramics, machinable ceramics, bio-ceramics, electrical ceramics, glass semiconductors in thermal insulation, optical materials, etc. [1][2][3][4][5][6][7][8][9][10]. High strength and lightweight are required for some applications.…”

Section: Introductionmentioning

confidence: 99%

High strength glass-ceramics sintered with coal gangue аs а raw material

Dang

2019

Sci Sintering

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“…For decades, synthetic glass-ceramics have been studied to understand their thermal behavior and also the relationship between composition, processing and microstructure. In the last decades, different applications for glass-ceramics have been studied based on their mechanical [2][3][4][5], thermal [6][7][8], electrical [9][10][11][12], biological [3,[13][14][15][16], and optical [17- 19] properties, among others. Glass-ceramics are produced from a controlled crystallization of a glass that generates a microstructure formed by one or more crystalline phases, eventually some porosity, and a residual glassy phase, since crystallinity ranges from 0.5 to 99.5%, although it achieves typical values between 30 and 70% [20].…”

Section: Introductionmentioning

confidence: 99%

Solid-state reaction in nanoparticulate alumina/LZSA glass-ceramic composites

2018

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In this work, some properties, such as sinterability, modulus of elasticity (E), coefficient of thermal expansion (CTE) and dielectric constant (ε r ), of composites constituted by nanoparticulate alumina (27-43 nm, 35 m 2 .g -1 ) in different contents (0 to 77 vol%) and a LZSA glass-ceramic composition (17.7Li 2 O-5.2ZrO 2 -68.1SiO 2 -9.0Al 2 O 3 , molar basis) were evaluated. Dry powders of the raw materials (alumina and LZSA parent glass, frit) were uniaxially pressed (40 MPa) and the obtained compacts were sintered at 600-950 °C (1 h holding time). X-ray diffraction (XRD) study was performed in order to investigate the solid-state reactions occurred in LZSA-based compositions during sintering. XRD results were correlated to the CTE, E and ε r of sintered samples. The CTE of the obtained composites decreased as alumina content increased mainly due to the β-spodumene ss (solid solution Li 2 O.Al 2 O 3 .4-10SiO 2 ) formation. The results concerning the E (22.3±1.5 GPa) and ε r (3.1±1.3) for the composite with 5.6 vol% addition sintered at 850 °C for 1 h indicated, in a preliminary way, the possibility of development of materials with suitable properties for applications concerning to the low temperature co-fired ceramic (LTCC) technology.

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“…This fact is in opposition to the expected behavior, since alumina is an insulating material, as for example the values measured at low temperatures, in this case 300 ºC, the conductivity obtained is about 8 orders of magnitude higher that expected for alumina and silica, which exhibits conductivities around 10 -14 S.cm -1 at this temperature. But the conduction process of these materials is heavily influenced by the concentration of Li ions that have high mobility, exhibiting ionic conductivities as reported in the literature 26,29,31,35 . The activation energy for all cases decreased with increasing addition of alumina.…”

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confidence: 98%

“…It is possible to observe that there was a slight decrease in Vickers microhardness values with the addition of Al 2 O 3 . This fact can be explained for although the amount of the β-spodumene crystalline phase which has a hardness value lower than that of zircon [29][30][31] . Furthermore, considering the increase of porosity with an increase of the addition Al 2 O 3 , is possible residual porosity exerts a negative influence on the mechanical properties of the sintered ceramics [32][33][34] .…”

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confidence: 99%

LZS/Al2O3 Glass-Ceramic Composites Sintered by Fast Firing

et al. 2017

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In this work, nanometric Al 2 O 3 (1-5 vol.%) particles (13 nm, 100 m 2 /g) were added to a 19.58Li 2 O•11.10ZrO 2 •69.32SiO 2 (mol%) (3.5 µm, 2.5 m 2 /g) parent glass-ceramic matrix to prepare composites with the purpose of studying the influence of Al 2 O 3 on their structure, microstructure, mechanical, thermal and electrical properties when sintered by fast firing. The parent glass-ceramic was prepared by melting and fast cooling (in water) to obtain a glass frit. The resulting glass frit was milled according to a two-step procedure consisting on a dry milling stage followed by a long wet milling step down. Each composition was wet homogenized and then dried at 110 ºC for 48 h for disaggregation. The obtained powders were uniaxially pressed (100 MPa) and compacts sintered by fast firing (175 ºC/min) between 800 and 900 ºC for 30 min. The composites, with relative densities ranging from 89% to 93%, showed zircon and β-spodumene as main crystalline phases. The hardness and Young's modulus varied from 4.5 to 6.5 GPa, and from 65 to 102 GPa, respectively. The formation of β-spodumene in the obtained composites leads to reduce the CTEs, whose values ranged from 13 to 7 x 10 -6 ºC -1 .

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Evaluation of electrical properties of glass-ceramics obtained from mill scale

Cited by 16 publications

References 49 publications

High strength glass-ceramics sintered with coal gangue аs а raw material

High strength glass-ceramics sintered with coal gangue аs а raw material

Solid-state reaction in nanoparticulate alumina/LZSA glass-ceramic composites

LZS/Al2O3 Glass-Ceramic Composites Sintered by Fast Firing

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