Producing the lead-free BaFe0.5Nb0.5O3 ceramics with multiferroic properties

In the work the BaFe0.5Nb0.5O3 barium iron niobiate material (abbreviated to BFN) in a form of a ceramic, as a result of a synthesis of simple oxides: BaCO3, Fe2O3 and Nb2O5, was obtained. Synthesizing was conducted by a calcination method at high temperature of 1250 degrees C for 4 h. Compacting (sintering) was made by a free sintering method in the following conditions: T-sp =1350 degrees C, changing the sintering time t(s) from 2 to 5 h, at a linear heating rate of 300 degrees C/h. Examinations of an influence of the sintering time of the BFN ceramics on its density, microstructure, direct current electric conduction and dielectric properties were performed. Those examinations have shown that longer sintering times at temperature T-sp=1350 degrees C increase the values of the maximum electric permittivity. An excessive increase in the sintering time has a disadvantageous effect on the direct current electric conduction (including dielectric losses) and on the degree of the phase transition diffusion. Analyzing the results obtained, it can be stated that the BFN specimens sintered at temperature T-sp=1350 degrees C and in the sintering time t(s) from 3 to 4 h are characterized by the best set of parameters. (C) 2009 Elsevier B.V. All rights reserved.