Nb-doped PZT material by sol-gel combustion

Nanocrystalline niobium doped lead zirconate titanate powders (PZTN) were prepared by a citratenitrate sol-gel combustion technique. The technique involves three steps: preparation of stable and homogeneous sol, formation of gel, combustion of gel. The solwas 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 400æC for 4 h. The particles were found to be irregular aggregates of nanosized primary particles (crystallite size about 30 nm). Different milling treatments were performed in order to improve the sinterability. Ball milled (100 h with PEG) powders were sintered at 1100æC for 2 h in air showing 97% relative density at a densification T 100æC lower than following the conventional mixed oxide route. The stoichiometry of the system was determined at each stage of the process and no fluctuation was detected.