Crystallization of lead zirconate titanate without passing through pyrochlore by new solution process

We report a novel low-temperature crystallization path for perovskite lead zirconate titanate (PZT) from solution. The modification of a PZT solution by monoethanolamine (MEA) resulted in a change in the crystallization behavior. MEA was strongly coordinated to the metal ions, resulting in destroy of multinuclear metal organic complexes. This led to a remarkably increased pyrolysis temperature, and Pb ²⁺ was reduced into Pb ⁰ because of a reducing environment at 200-300°C. Nanoscopic separations of Pb ⁰ was later transformed into uniformly distributed α-PbO nanocrystals and clusters in the amorphous Zr/Ti-O matrix, and finally the sample crystallized into perovskite at 400-500°C. On the other hand, pyrochlore phase was observed in the conventional crystallization process. The avoidance of pyrochlore formation is the key for the low-temperature crystallization of perovskite. X-ray absorption fine structure (XAFS) analysis was performed to reveal the structures in solutions and amorphous phases.