Low-temperature chemical synthesis of lead zirconate titanate (PZT) powders free from halides and organics

A water-soluble peroxytitanato complex [Ti(OH)3O2]- was prepared through the reaction between Ti metal and hydrogen peroxide at pH = 11. A solution of lead nitrate and zirconyl nitrate was added to the peroxytitanic acid solution, and a stoichiometric and amorphous precipitate of a mixed oxide of lead, zirconium and titanium was formed, which was filtered off and washed to eliminate nitrate ions. The precipitate was calcined between 600 and 1000 C using a closed alumina boat. The precipitate was characterised by TG-DTA, ICP (Pb, Zr and Ti), elemental analysis (C, H, N and O), Raman spectroscopy and XRD, and the calcined PZT powders were characterised by Raman spectroscopy and XRD. The amorphous precipitate showed a weight loss of 26% in the range from 30 to 500 C, revealing that the crystallisation process starts at low temperature. Rhombohedral Pb(Zr0.60Ti0.40)O3 was obtained at temperatures above 900 C. It is of particular importance that the use of the peroxytitanato complex provided a method to synthesise PZT powders without the use of any organics (including alkoxides) or reagents containing undesirable halides. 38 refs.