Effect of annealing on the thermoelectric properties of directionally grown Bi2Sr2Co.8Ox ceramics

Abstract

The effect of annealing on directionally solidified Bi 2Sr 2Co 1.8O x ceramic rods has been studied for different times up to 1008 h. Microstructure has shown five different phases in the as-grown materials which have been reduced to two major ones after 1008 h thermal treatment, accompanied by an important grain growth. These microstructural changes are reflected on the mechanical properties which are higher than those measured in the as-grown materials in all cases. Moreover, they also produce an important decrease on the resistivity and increase of thermopower, leading to a raise on the power factor on thermally treated samples, about two times, compared to the as-grown samples. © 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.