Influence of grain size on the phase transition β2 → ɛ in Bi4La2O9 material

This paper deals on a study realized in order to elaborate dense ceramic of Bi4La2O9 oxide conductor. A wet method in nitric media, usually favorable to obtain low grain size, did not allow to isolate the stable phases. Material with particle low size has been obtained by attrition treatment after conventional solid state powder synthesis. The decrease of particle size (≅4 times), evidenced by X-ray diffraction and SEM, influences the reversibility of transitions between monoclinic ɛ and rhombohedral β2 varieties on powder, as well as ceramics, leading to an improvement of the conductivity level of these ones after a thermal cycle.