The effects of boundaries upon conductivity were investigated by using samples of sintered (Bi2O3)0.75(WO3)0.25 and (Bi2O3)0.7(SrO3)0.3. The conductivities of specimens with various grain sizes were measured by means of alternating-current impedance analysis. The grain conductivity and the grain-boundary conductivity were not separate in the complex impedance plane, and specimens with a large grain size exhibited almost the same conductivity as specimens with a small grain size. In the case of the Bi2O3 system, it was concluded that the electrical properties of the grain boundary were not different to those of the grains; regardless of their crystal structure.

Y.J.Lee, C.O.Park, H.D.Baek, J.S.Hwang: Solid State Ionics, 1995, 76[1-2], 1-4