Effect of CaO additive on sintering and crystallization behavior of cordierite glass–ceramic prepared by sol–gel method

Malekzadeh, H.; Rezvani, M.

doi:10.1007/s10971-013-2992-y

Cited by 7 publications

(9 citation statements)

References 13 publications

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“…Cordierite is crystallized beginning from 1200ºC at the expense of enstatite, mullite, cristobalite and diopside (Table 3) [21,22,24,55,57]. This is aided by the high contents of TIOs of the batches (2.03-11.44wt.%, Table 2) which accelerates the solid-state formation of orthorhombic cordierite by lowering its crystallization temperature [20,24,27,[58][59][60]. In addition, the TIOs initiate the early formation of silicate-rich melt (68.52-81.39wt.%) at 1355 and 1400ºC, respectively, which is aided by the partial dissolution of mullite, enstatite and cristobalite.…”

Section: Phase Compositionmentioning

confidence: 99%

Electrical, Microstructural and Physical Characteristics of Talc-based Cordierite Ceramics

Yahya

Soltan

Mahani

et al. 2022

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The aim of this work is to study the effect of various talc rocks for the preparation of talc-based cordierite ceramics. Raw talc and sintered cordierite-based ceramic samples (1000-1375ºC for 2 h) were characterized using XRD, XRF, TGA-DTG, laser PSDs, Archimedes method, SEM-EDAX and dielectric relaxation spectrometer (DRS). Results show that impurity oxide contents, particle size and mineralogical changes of green batches influenced the microstructure densification and crystallization of orthorhombic and hexagonal cordierite. The complex electric modulus plot shows the existence of two relaxation processes associated with the capacitive contribution grain boundaries and grain at low and high frequencies, respectively. The dielectric loss reached much lower values (0.0004–0.0007) for the ceramics composed of higher cordierite phase composition (87.00 to 92.00wt.%) that sintered at 1350 and 1375ºC. Such ceramics could be promising in electronic applications like capacitors, microwave devices and wireless communication.

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Section: Phase Compositionmentioning

confidence: 99%

Electrical, Microstructural and Physical Characteristics of Talc-based Cordierite Ceramics

Yahya

Soltan

Mahani

et al. 2022

Silicon

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“…These materials are also conventionally utilized in the electronic industry [4][5][6][7][8]. The synthesis of cordierite glass-ceramics is carried out by several methods (sol-gel, solid-state reaction, and crystallization from glass) [9][10][11]. There are three polymorphic forms of magnesium cordierite (Mg2Al4Si5O18): metastable phase (solid solution with a β-quartz structure) called µ-cordierite, β-cordierite phase (low-temperature orthorhombic), and indialite or α-cordierite (high-temperature hexagonal) [6,12,13].…”

Section: Introductionmentioning

confidence: 99%

Crystallization behavior and structural evaluation of cordierite base glass-ceramic in the presence of CaO and B2O3 additives

Ghahsareh

rezvani

2022

Synth. Sinter.

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The purpose of the present work is to highlight the role of CaO and B2O3 additives on the crystallization behavior and microstructural properties of stoichiometric cordierite glass-ceramics using differential thermal analysis (DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Vickers micro-hardness and scanning electron microscopy (SEM). The results show that the presence of B2O3 and CaO in the initial glass led to the precipitation of only one exothermic peak (α-cordierite: Mg2Al4Si5O18). During the heat treatment process, the presence of calcium oxide favors crystallization of anorthite (CaAl2Si2O8) besides α-cordierite phase. It is worth mentioning that, CaO and B2O3 additives strongly encourage the formation of α-cordierite and have the opposite effect on the crystallization of μ-cordierite. In order to determine the effect of crystallization and B2O3 and CaO additives on the hardness of specimens, the micro-hardness measurement of glasses and glass-ceramics shows that the glass-ceramic containing CaO (MAS5C) exhibits the highest micro-hardness value, which depends on the high crystallinity value in this specimen.

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“…However, reaction sintering abundant natural clay minerals and/or waste [4,7,[18][19][20][21][22][23][24] remained the preferred way to produce unexpansive cordierite materials. Intentionally, additives such as nickel dioxide [25], zinc [26], phosphorous and boron oxides [27], phosphorous oxide [28], ceria [29], nickel dioxide and titania [30], barium oxide [31], magnesia [32,33], and calcium oxide [8,[34][35][36][37] are added to ease the nucleation and growth of cordierite.…”

Section: Introductionmentioning

confidence: 99%

“…[34] prepared magnesia-alumina-silica based glass ceramics by melting method using pure chemical reagents and found that certain content of CaO promotes the glass crystallization, and transfers sapphirine to ɑ -cordierite. Also, addition of CaO in the presence [35] or absence of B 2 O 3 [36] was reported to improve sintering and the formation of cordierite in glass-ceramics prepared via sol-gel method. Similar trend was observed by Guo-hua Chen [37] who investigated the influence of replacing magnesium oxide by calcium oxide on phases formed in the magnesia-alumina-silica system.…”

Section: Introductionmentioning

confidence: 99%

“…The formation of cordierite and phase transformation kinetics in cordierite materials [8,[25][26][27][28][29][30][31][38][39][40][41] were characterized by differential thermal analysis [28][29][30][31][38][39], differential scanning calorimetry [8,[39][40], and x-ray diffraction [8,[25][26][27]. Isothermal [25][26][27]35] and non-isothermal [8,25,[28][29][30][31][38][39][40][41] experiments were carried out and activation energy values from 170 to 964 kJ/molwere reported [8,2,3,[25][26][27][28][29][30][31]…”

Section: Introductionmentioning

confidence: 99%

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Formation of anorthite containing cordierite materials through reaction sintering kaolin, MgO and CaO precursors

et al. 2020

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The effect of CaO on cordierite formation from kaolin-MgO-CaO powder mixtures, milled for 5 h and reaction sintered for 2 h in the temperature range 900-1400?C, was investigated. Phases formed in the developed materials were characterized by x-ray powder diffraction method (XRD) and Raman spectroscopy. Non-isothermal differential thermal analysis (DTA) and thermogravimetric (TG) experiments were performed from room temperature to 1400?C, at heating rates from 20 to 40?C/min. Activation energies were determined using Kissinger method. It was found that sintering the stoichiometric kaolin-magnesia mixture led to the nucleation and growth of monolithic cordierite; while cordierite along with anorthite were present in the other two samples where 4 or 8 wt% of CaO was added. The increase in CaO decreased cordierite formation temperature and increased the activation energy, which ranged from 445 to 619 kJ/mol for ?-cordierite and from 604 to 1335 kJ/mol for ?-cordierite.

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Effect of CaO additive on sintering and crystallization behavior of cordierite glass–ceramic prepared by sol–gel method

Cited by 7 publications

References 13 publications

Electrical, Microstructural and Physical Characteristics of Talc-based Cordierite Ceramics

Electrical, Microstructural and Physical Characteristics of Talc-based Cordierite Ceramics

Crystallization behavior and structural evaluation of cordierite base glass-ceramic in the presence of CaO and B2O3 additives

Formation of anorthite containing cordierite materials through reaction sintering kaolin, MgO and CaO precursors

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