Thermal evolution of (Zr,Ti)O2 gels synthesized at different basicpH

(Zr, Ti)O₂ gels as precursors of zirconium titanate (ZT) powders were prepared by the sol-gel method, which involves hydrolysis of ZrClO₂+TiCl₄ in the presence or absence of hydrogen peroxide, in twopH ranges, 8–9 or 11–12. Thermal evolution of these precursors has been studied by DTA, BET surface area, XRD and SEM. Differences in DTA curves, surface area and morphology were observed. In particular, ZT prepared atpH=8–9 with hydrogen peroxide was purer, more homogeneous and presented a different morphology compared to ZT processed atpH=11–12; hydrated/hydroxylated Zr?Ti species were formed to a greater extent in the latter case. Addition of hydrogen peroxide during chemical processing of these gels plays a key role in controlling the crystallization temperature of ZT.