Reaction kinetics of mechanically activated cordierite-based ceramics studied via DTA

Abstract

Since cordierite, 2MgO center dot 2Al(2)O(3)center dot 5SiO(2) (MAS), is a very useful high-temperature ceramic material, it is important to decrease its sintering temperature. In order to accelerate the process of sintering, 5.00 mass% MoO3 was added to the starting mixtures. The mechanical activation of the starting mixtures was performed in a high-energy ball mill in time intervals from 0 to 160 min. After the activation, starting mixtures were sintered at 1300 A degrees C for 2 h. In order to determine the impact of mechanical activation on particle size distribution and powders morphology, the mechanically treated powders were characterized by a laser light-scattering particle size analyzer and scanning electron microscopy. The phase composition of the starting mixtures and sintered samples was analyzed by the X-ray diffraction method. In order to determine temperature intervals of chemical reactions and phase transitions, differential thermal analyses (DTA) and thermo-gravimetric analysis were used. Kissingers equation was employed to calculate apparent activation energies of various processes that occur within the system during heating. Based on the obtained DTA results, it was established that mechanical activation along with MoO3 additive has influence on sintering temperature which was decreased for more than 100 A degrees C, comparing to the literature data.