Use of laser technology to produce high thermoelectric performances in Bi2Sr2Co1.8Ox

Bi2Sr2Co1.8Ox bulk polycrystalline ceramics were prepared by conventional sintering of powders, obtained by polymer solution method and by directional growth using the laser floating zone technique. Microstructural analysis showed randomly oriented grains in the classical sintered materials, while i...

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Bibliographic Details
Authors: Rasekh, Sh., Costa, F. M., Ferreira, Nuno M., Torres, M. A., Madre, M. A., Diez, J. C., Sotelo, Andres
Format: article
Status:Versión enviada para evaluación y publicación
Publication Date:2015
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/121179
Online Access:http://hdl.handle.net/10261/121179
Access Level:Open access
Keyword:Thermoelectrics
Laser processing
Seebeck coefficient
Electrical resistivity
Description
Summary:Bi2Sr2Co1.8Ox bulk polycrystalline ceramics were prepared by conventional sintering of powders, obtained by polymer solution method and by directional growth using the laser floating zone technique. Microstructural analysis showed randomly oriented grains in the classical sintered materials, while in the laser-textured samples well oriented crystals with the c-axis nearly perpendicular to the growth direction were observed. A significant reduction on electrical resistivity, compared with the sintered materials, was observed due to the decrease on the secondary phases content. As a consequence, a raise on the power factor of about 2 and 5 times, compared with the classically sintered samples, was obtained for the as-grown and annealed laser-textured samples, respectively. The maximum power factor obtained at 650 °C in the annealed laser-textured samples (∼0.20 mW/K2 m) is much higher than the best value obtained in sinter–forged textured materials at the same temperature.