HIGH-TEMPERATURE IONIC AND ELECTRONIC CONDUCTION IN ZIRCONATE AND HAFNATE COMPOUNDS

In the present work, samples of the zirconate compounds CaZrO3, SrZrO3 and BaZrO3 and the hafnate compounds CaHfO3, SrHfO3 and La2Hf2O7 have been synthesized. It was found that these compounds feature high ionic conductivity at temperatures from 1000 to 1600-degrees-C. Contributions of partial electronic conductivity were measured on EMF cells using Al(1) + Al2O3)(s) and Cr(s) + Cr2O3(s) mixtures as electrode systems. Results are given in terms of the characteristic parameter P(e), (t(ion)=0.5) as a function of reciprocal temperature. It is demonstrated that ionic conductivity of the investigated zirconate and hafnate compounds is at least equal and in some cases superior to that of conventional zirconia stabilized with CaO and MgO.