An oxalate–peroxide complex used in the preparation of dopedbarium titanate

Abstract

A method is described for the preparation of homogeneously doped barium titanate, which can be applied in non-linear dielectric elements. Ba and Ti salts are dissolved, mixed with hydrogen peroxide and added to a solution of ammonium oxalate, resulting in the formation of an insoluble peroxo–oxalate complex. The presence of oxalate ions and a high pH are necessary for the formation after calcination of a stoichiometric and sinterable powder. To characterise the structure of the precipitating complex, the thermal decomposition of the complex is studied by means of XRD, d-TGA and FTIR. It is found that the precipitating complex is BaTi_0.91Zr_0.09O₂(C₂O₄)2H₂O. The calcined powder prepared with the peroxo–oxalate method contains no second phase, in contrast to powders prepared with the oxalate method and the peroxide method.