Kinetic analysis of the formation of high-temperature phases in an illite-based ceramic body using thermodilatometry

A non-isothermal kinetic analysis of the sintering process of an illitic clay is studied by thermodilatometry. For this study, illitic clay with over 80 mass% of illite content, originated in the Füzérradvány location in northeastern Hungary, is used as basic material. The measurements are performed using a push-rod dilatometer on compact samples with heating rates from 1 to 10 °C min −1 in dynamic N 2 atmosphere. The Kissinger method is used for the parameterization of the process. The results show that the reaction sintering runs in several overlapping steps. The determined values of the apparent activation energy of the first step and second step are E A = (625 ± 18) kJ mol −1 and E A = (575 ± 14) kJ mol −1 , respectively. The results also show that both reactions could be characterized by the thickening of long cylinders (needles) or growth of needles and plates of finite long dimensions.