Formation of Lead Zirconate Titanate Powders by Spray Pyrolysis

• Published in: Journal of the American Ceramic Society Vol. 86; no. 9; pp. 1474 - 1480
• Main Authors: Nimmo, William, Ali, Naseef J., Brydson, Rik M., Calvert, Clair, Hampartsoumian, Edward, Hind, David, Milne, Steven J.
• Format: Journal Article
• Language: English
• Published: Westerville, Ohio American Ceramics Society 01-09-2003; Blackwell; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Chemistry; Colloidal state and disperse state; Electrotechnical and electronic ceramics; Exact sciences and technology; General and physical chemistry; lead zirconate titanate; Powders; spray pyrolysis; Technical ceramics; Scanning electron microscopy; Pyrolysis; Lead titanates; Spraying; Ferroelectric ceramics; PZT; Experimental study; X ray diffraction; Precursor; Oxide ceramics; Lead zirconates; Powder; Transmission electron microscopy; Chemical preparation; Manufacturing; Lead Titanates Zirconates; Aqueous solution; Atomization; Microstructure; Growth from solution; Electroceramics
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.2003.tb03499.x

Twin‐fluid atomization spray pyrolysis (SP) has been investigated for the production of lead zirconate titanate (PZT) powders, using aqueous solutions of lead acetate and zirconium and titanium alkoxide precursor reagents. The particle size distribution of the PZT powder showed a d50 value of 0.3 μm, but with a small fraction of relatively large particles, several micrometers in size. Most particles were spherical but many of the largest particles, in the size range ca. 1–5 μm, were irregular. It was demonstrated that the morphology of the final PZT powder was controlled by decomposition processes occurring during the initial drying stages, at ≤200°C. A pyrochlore or fluorite‐type intermediate crystalline phase was present in the final powders, but when the maximum reactor temperature was raised, and/or when the levels of excess lead in the starting solutions were increased, the proportion of the desired perovskite phase increased. However, at the highest process temperatures studied, ∼900°C, small crystallites of another phase formed on the surface of the PZT particles; these were probably lead oxide carbonate particles. Overall, a starting solution composition containing around 5 mol% excess Pb, and a maximum reactor temperature of 800°C, were selected as offering the most suitable conditions for producing PZT (52/48) powder, with minimal secondary phases(s). Preliminary densification studies showed that the powders could be sintered at 1150°–1200°C to give pellets of 95%–96% theoretical density.