Electrical conductivity and ionic transference number of Sr and Ba beta-aluminas

Ba and Sr beta-alumina ionic conductors were synthesized by solid state sin tering at 2033 to 2073 K and their electrical conductivities were measured by a.c. impedance spectroscopy. The electrical conductivities at 1673 K wer e 2.05 x 10(-2) and 4.6 x 10(-3) S m(-1) for Sr and Ba beta-aluminas, respe ctively. An oxygen concentration cell and d.c. polarization methods were ap plied to measure the ionic transference numbers. The values obtained by the two methods were almost in agreement at more than 1400 and 1673 K for Sr b eta-alumina and Ba beta-alumina, respectively. Sr beta-alumina could have s lightly greater ionic transference numbers than Ba beta-alumina. (C) 1999 E lsevier Science B.V. All rights reserved.