High thermoelectric performance in Bi2-xPbxBa2Co2Oy promoted by directional growth and annealing
authors Madre, MA; Costa, FM; Ferreira, NM; Costa, SIR; Rasekh, S; Torres, MA; Diez, JC; Amaral, VS; Amaral, JS; Sotelo, A
nationality International
journal JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
author keywords Ceramics; Doping; Grain growth; Electrical properties; Thermopower
keywords CO-O; SYNTHETIC METHODS; CERAMICS; BI2CA2CO1.7OX; MICROSTRUCTURE; SUBSTITUTION; IMPROVEMENT; COBALTITES; OXIDES; PHASE
abstract Bi2-xPbxBa2Co2Oy (x=0.0, 0.2, 0.4, and 0.6) misfit compounds were grown by the laser floating zone technique. Microstructural analysis has shown the formation of thermoelectric grains together with high amount of secondary phases. Thermoelectric grains orientation is increased until 0.4Pb, while further substitution drastically destroys the preferential grain orientation. Electrical resistivity is very low compared with the values obtained in sintered materials, spectacularly increasing power factor. Moreover, the performance of these materials was further improved subjecting the as-grown samples to a postannealing step due to the rise of thermoelectric phase content. These microstructural modifications led to a high decrease of electrical resistivity, improving power factor in around a factor two at room temperature, compared with the as-grown samples. Moreover, the low thermal conductivity of the textured annealed samples leads to a maximum estimated ZT value of 0.53 for the 0.2 Pb-doped samples, much higher than the reported in literature. (C) 2015 Elsevier Ltd. All rights reserved.
publisher ELSEVIER SCI LTD
issn 0955-2219
year published 2016
volume 36
issue 1
beginning page 67
ending page 74
digital object identifier (doi) 10.1016/j.jeurceramsoc.2015.09.034
web of science category Materials Science, Ceramics
subject category Materials Science
unique article identifier WOS:000364254700008
  ciceco authors
  impact metrics
times cited (wos core): 7
journal impact factor (jcr 2016): 3.411
5 year journal impact factor (jcr 2016): 3.327
category normalized journal impact factor percentile (jcr 2016): 98.077
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