Kinetic Study of Zirconia Crystallization from Amorphous ZrO2-SiO2 Composite Precursors Processed by Sol-Gel Chemistry

Powder precursor gels with composition xZrO(2).(100-x)SiO2, with selected values of x = 8, 24, 43 and 75 mol%, were processed by sol-gel chemistry. Differential thermal analysis (DTA) was used to study crystallization in (cubic/tetragonal)-ZrO2 during the heating of the reactive amorphous precursors. Kinetic parameters such as activation energy, Avrami's exponent and frequency factor have been simultaneously calculated from the computed DTA data using a previously reported kinetic model. The crystallization temperature decreases relative to the increase in the amount of ZrO2, the value of the kinetic parameter of the crystallization being related to the value of x.