Anomalous grain growth in sintered Bi2Ca2Co2−xCuxOy + Ag ceramic composites by Cu doping

Autor: H. Amaveda, M. A. Madre, M. Mora, M. A. Torres, A. Sotelo
Přispěvatelé: Conferencia de Rectores de las Universidades Españolas, Consejo Superior de Investigaciones Científicas (España), Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Gobierno de Aragón, European Commission
Rok vydání: 2023
Předmět:
Zdroj: Journal of Materials Science: Materials in Electronics. 34
ISSN: 1573-482X
0957-4522
Popis: Bi2Ca2Co2 − xCuxOy + 4 wt%Ag (with x between 0 and 0.20) thermoelectric materials were prepared through a sol-gel method via nitrates. Powder XRD patterns showed the presence of thermoelectric phase as the major one, accompanied by metallic silver. SEM observations identified three different secondary phases in the samples, together with an exaggerated grain growth with Cu doping. The microstructural modifications are reflected in an important decrease of electrical resistivity, ∼ 3% when compared to undoped samples, due to the reduction on the number of grain boundaries, and the increase of Co4+ in the conducting layer. The minimum values at 650 ºC were obtained in 0.10 Cu-doped samples, 69 mΩ cm, which are lower than the reported in sintered samples. On the other hand, Seebeck coefficient was only slightly affected and reached the highest values at 650 ºC in 0.15 Cu-doped samples, 215 µV/K, which is practically the same measured in undoped ones, 211 µV/K, and lower than those reported for sintered samples. Consequently, the highest PF at 650 ºC has been determined in 0.10 Cu-doped samples, which is around 50% higher than the obtained in samples prepared through the classical solid-state method, or the undoped ones prepared in this work.
Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.
This research has been supported by the Spanish MINECO-FEDER project (Grant No. MAT2017-82183-C3-1-R) and the Aragón Government (Research Group T54-20R).
Databáze: OpenAIRE
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