Microstructure and thermoelectric properties of Al-doped ZnO ceramic prepared by spark plasma sintering

Precious Manti Radingoana, Sophie Guillemet-Fritsch, Jacques Noudem, Peter Apata Olubambi, Geoffroy Chevallier, Claude Estournès

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

The high thermal and low electrical conductivities of ZnO ceramics have hindered their thermoelectric applications. The doping of ZnO with group 3 elements can enhance the thermoelectric properties. In this work, Al (2 at%) doped ZnO powder was sintered using spark plasma sintering at varying parameters (such as temperature (550–700 ℃), pressure (250–500 MPa) and the temperature of pressure application (Room Temperature (RT) and Holding Time (HT))). Maximum relative density of 98.9% was achieved at a temperature and pressure of 650 °C and 250 MPa, respectively. The Al-doped ZnO ceramics improved in electrical conductivity which caused a decrease in the Seebeck coefficient because of increased carrier concentration. The reduction in the grain size due to inhibiting growth effects of aluminum lead to a decrease in the thermal conductivity through phonon scattering at the grain boundaries. Hence, ZT of 0016 at 500 °C was obtained. This study indicated that Al-doped ZnO ceramics can be sintered at very low temperature of 650 °C. These conditions allow to retain the nanostructure, which is beneficial in improving the thermoelectric properties.

Original languageEnglish
Pages (from-to)1009-1016
Number of pages8
JournalJournal of the European Ceramic Society
Volume43
Issue number3
DOIs
Publication statusPublished - Mar 2023

Keywords

  • Aluminum
  • Ceramics
  • Spark plasma sintering
  • Thermoelectric properties
  • ZnO

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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