Microcharacterisation of grain-oriented ceramics based on Bi3TiNbO9 obtained from mechanochemically activated precursors

Hot pressing was applied to a novel powder, synthesised by the mechanochemical activation of starting oxides, in order to obtain dense ceramics of Bi3TiNbO9 for use as piezoelectric material at high temperatures. Since these compositions belong to the family of layered perovskites, hot pressing produces a preferential orientation of the grains. An assessment of the degree of orientation achieved was carried out by quantitative texture analysis using experimental X-ray pole figures. Although texture could be considered as the most influential factor on the final properties, other microstructural features were studied by transmission electron microscopy including grain boundaries and ferroelectric domains. The results of the microcharacterisation of these ceramics are discussed in order to understand the process involved in the development of preferential orientation in these ceramics.