Effect of temperature and magnesia on phase transformation kinetics in stoichiometric and non-stoichiometric cordierite ceramics prepared from kaolinite precursors

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

“…In order to characterize the phases formed in the samples, a diffractometer MRD, PANalytical (ISM) with CuKα radiation of a wavelength 0.15418 nm, and a BRUKER SENTERRA Raman spectroscopy apparatus were used. Activation energies were determined from DTA results [2][3].…”

“…The Kissinger method as explained presented in reference [3] was "used to calculate the non-isothermal activation energy (E A ) for the formation of cordierite according to equation" 1.…”

“…It is known that kaolin, a natural clay mineral composed primarily of Al 2 O 3 and SiO 2 , experiences many reactions and transformations where the oxides and additives react to yield mullite [1] or cordierite [2,3] based materials. As one of the main phases of the magnesiaalumina-silica system, cordierite has values of 2.53 g/cm 3 , 1470 °C, and ˃ 10 12 Ω cm for its density, melting temperature, and electrical resistivity, respectively. Additionally it has very low thermal expansion (values of α between 1 ×10 -6 2 × 10 -6 C -1 ) and conductivity.…”

“…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]…”

“…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][38][39][40][41][42][43]. Recently, the authors synthesized low-cost stoichiometric [2] and non-stoichiometric [3] cordierite ceramic materials, by reaction sintering Algerian natural clay minerals and synthetic magnesia, and studied the effect of temperature and MgO on cordierite formation. The objectives of this study are to investigate and report the influence of CaO content on the kinetics of cordierite formation from kaolin-MgO-CaO powder mixtures and explore the possibility to reduce the synthesis temperature.…”