Chemical co-precipitation of mixed (Pb plus Ti) oxalates precursor for the synthesis of PbTiO3 powders

A chemical co-precipitation route is developed to precipitate mixed oxalates (PbC2O4 + TiOC2O4.2H(2)O) at room temperature. In this synthesis route, an anionic TiO(C2O4)(2)(-2) species obtained by dissolving potassium titanyl oxalate (KTO) (0.01 M) stable over narrow pH range are destabilized with the addition of 0.01 M solution of lead chloride (PbCl2) to produce insoluble TiOC2O4.2H(2)0 and oxalic acid. The in situ generated oxalic acid during destabilization process reacts with Pb2+ ions to precipitate lead oxalate (PbC2O4). The mixed oxalates on pyrolysis in air at 750degreesC/4 h produced submicron sized (0.13-0.15 mum) stoichiometric PbTiO3 (PT) powders having tetragonal symmetry (with c/a ratio similar to 1.063) which form agglomerates of size 0.5-5 mum. Various physico-chemical techniques were used to characterize the as-dried mixed oxalates precursor and PbTiO3 powders. All these experimental results related to synthesis and characterization of these powders are presented in this paper. (C) 2002 Elsevier Science B.V. All rights reserved.