Low temperature synthesis of PZT powders via microemulsion processing

Lead zirconate titanate (PZT) powders with composition near the morphotropic phase boundary have been synthesized via a microemulsion processing route. The microemulsion system used consists of cyclohexane as the oil phase, mixed poly(oxyethylene)(5) nonyl phenol ether and poly(oxyethylene)(9) nonyl phenol ether as the nonionic surfactants, and an aqueous solution containing cations of lead, zirconium, and titanium as the water phase. Coprecipitation of the hydroxide precursors was effected through addition of an aqueous ammonia solution into the microemulsions. Such a microemulsion processing route allows a homogeneous mixing of constituent metal cations in the precursors. Crystalline tetragonal PZT powders were obtained by calcining the precursors at a temperature as low as 450 degrees C in air without the formation of any intermediate phases. The resulting precursors and PZT powders have been characterized using techniques such as X-ray diffraction for phase analysis and thermogravimetric analysis, differential thermal analysis, scanning electron microscopy, and light-scattering technique for particle size and particle size distribution measurements. (C) 1998 Elsevier Science Ltd.