Densification and Crystallization of Nonstoichiometric Cordierite Glass with Excess MgO Synthesized from Kaolin and Talc

Abstract

Densification and crystallization behaviors of nonstoichiometric cordierite synthesized from minerals through the glass route are reported in this paper. DTA of glass powder was conducted under isothermal and nonisothermal conditions. The activation energy was calculated from the dilatometry test at constant heating rate by using Arrhenius equation to observe their densification behavior. The densification and crystallization of composition with MgO mole ratio of 3.4 and 4.0 below 9001C were confirmed using nonisothermal DTA and dilatometry. However, samples below 2.6 mol MgO were not fully densified and crystallized when isothermally heated for 2 h. When MgO content was increased 2.0-3.0 mole ratio, the activation energy for densification decreased, but it increased for MgO mole ratio ! 3.4.

Effect of Excess MgO on the Properties of Cordierite Ceramic Sintered by Solid‐State Method

“…Comparing the products, the shrinkage obviously increased when the temperature was higher. Excess MgO doped can facilitate sintering, but at a low temperature, this effect does not significantly manifested (as shown in Fig. a).…”

“…A common conclusion was reached that appropriate additives could increase the cordierite phase and decrease the melting temperature and crystallization temperature. Banjuraizah et al . investigated the densification and crystallization of nonstoichiometric cordierite glass in detail.…”

“…Based on this point, basic magnesium carbonate can be used as pore‐forming agent. But additional MgO will stimulate crystallization and produce more liquid . Both have a great influence on the porosity.…”

Effect of reduced Al2O3 mole ratio on fabrication of cordierite ceramic by solid-state sintering method

“…As the sintering temperature increases, large amount of liquid glass phase appears, resulting in a further densification [18]. However, the simultaneous crystallization process can impede the densification process of the samples [19], and the existence of the holes also weakens the densification process [20]. Besides, abundant cordierite phase inhibits the shrinkage process as well because of its low coefficient of thermal expansion.…”

Effect of B2O3 on Phase Transformation of Cordierite Synthesized from Algerian Kaolin and MgO

“…Cordierite ceramics have been widely studied in recent years owing to their unique properties suitable for various industrial applications. It is characterized by extremely low dielectric constant and loss, high resistivity, low coefficient of thermal expansion, excellent thermal shock resistance, low density, stability at high temperature, good chemical stability and excellent insulation properties [1][2][3][4][5][6][7][8][9][10][11][12][13].…”