Nb-doped PZT material by sol-gel combustion

Nanocrystalline niobium doped lead zirconate titanate powders (PZTN) were prepared by a citrate-nitrate sol-gel combustion technique. The technique involves three steps: preparation of stable and homogeneous sol; formation of gel; combustion of gel. The sol was prepared by mixing stable solutions of Zr-oxynitrate, Pb-citrate, Nb- and Ti-peroxo-citrate precursors. The heat induced auto ignition leads to the decomposition of precursors and formation of pure perovskite phase after soaking at 400°C for 4h. The particles were found to be irregular aggregates of nanometric primary particles (crystallite size about 30nm). Different milling treatments were performed in order to improve the sinterability. Ball milled (100h with PEG) powders sintered at 1100°C for 2h in air showing 97% relative density at a densification T 100°C lower than following the conventional mixed oxide route. Nanosized powders were produced The stoichiometry of the systems was checked at each stage of the process and no fluctuation was detected.