Electrical conductivity and ionic transport number of Sr beta-alumina single crystals prepared by a floating zone method

摘要

Sr beta-alumina single crystals, Srl-0.25,Mg-1-(x)A1(10+x)O(17+0.25x) (0 <= x <= 0.41) were prepared in the SrO-MgO-Al2O3 system by a floating zone method. The single crystals had a cleavage plane, which is parallel to (001) plane. The electrical conductivity parallel (sigma(ll)) and perpendicular (sigma (perpendicular to)) to the cleavage plane had a maximum at x=0.2. The sigma(ll) was almost independent of oxygen partial pressure (Po-2), while sigma(perpendicular to) showed a Po-2(-1/6) dependence in the low Po-2, range (po(2) =10(-4) similar to 10(-13) Pa). The ionic transport numbers measured by a d.c. polarization method were almost unity in air at 1073 K to 1573 K. (c) 2005 Elsevier B.V. All rights reserved.