Mechanical and thermoelectric environmental evolution properties of Bi_2Sr_2Co_(1.8)O_x ceramics textured by laser floating zone technique

摘要

Bi_2Sr_2Co_(1.8)O_x ceramics have been synthesized through solid-state reaction methods and directionally grown from the melt by laser floating zone technique. Mechanical and thermoelectric characteristics of this material were determined by three point bending tests and the four probe technique, respectively. The mechanical and thermoelectric properties of Bi_2Sr_2Co_(1.8)O_x were determined as a function of the environmental conditions, air and water. Flexural strength data show that textured materials possess a high degradation resistance due to the low porosity of the external part of the rods (～65 μm), which avoids water infiltration and, as a consequence, the internal degradation. Moreover, power factor values are maintained practically unchanged for the samples immersed in water for 24 h.