Fluorite-type ceramics for high-temperature power installations

Ceramics based on cerium-dioxide are used mainly as highly refractory electrical conducting materials in high-temperature power installations, and also for making heating elements. Additions of pentavalent cations to cerium dioxide have an alloying action, and in the temperature range 300-1600C significantly increase its conductivity. In this paper the authors report on efforts to determine the region of existence of a single-phase solution of Ta2O5 in CeO2, to select a composition having the maximum electric conductivity, and to study its magnetic properties. The authors conclude that to obtain highly refractory ceramics that are electrically conducting in a wide temperature range, material containing 97% CeO2 and 3% Ta2O5 should be used. They state that the totally electronic (n type) nature of the conductivity ensures stability in the properties of the ceramics during the transmission of a direct current, and that these materials can therefore be used in industrial power installations.