A THERMAL STUDY OF THE SIO2-ZRO2 SOL-GEL SYSTEM

Silica-zirconia materials were synthesized by the sol-gel process at p H 3 and 9. The synthesis precursors were tetraethoxysilane and zirconi um acetate. The zirconia concentrations were 1.3%, 4.0% and 6.7%. The results obtained show that at pH 3 the tetragonal phase is present; at pH 9, the monoclinic phase is more stable. Thus, when the zirconia co ncentration is lower, the more stable crystalline phase is obtained in a number of steps.