Effect of ZnAl2O4 phase on thermoelectric properties of Al doped ZnO ceramics fabricated by spark plasma sintering

Dense and fine grained Zn 0·96 Al 0·04 O thermoelectric ceramics were fabricated by spark plasma sintering at 1173-1323 K. Apart from the host ZnO phase with a wurtzite structure, a trace of ZnAl 2 O 4 secondary phase was segregated at the grain boundary and showed an increasing trend with sintering...

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Bibliographic Details
Published in:Materials research innovations 2014-07, Vol.18 (sup4), p.S4-110-S4-115
Main Authors: Zhang, D.-B., Zhang, B.-P., Shang, P.-P., Gao, C., Zhang, Y.-Q.
Format: Article
Language:English
Subjects:
Aluminum
Ceramics
Grain boundaries
phase
Sintering
Spark plasma sintering
Thermal conductivity
Thermoelectric oxide
Thermoelectricity
Zinc oxide
ZnAl
ZnO
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Summary:Dense and fine grained Zn 0·96 Al 0·04 O thermoelectric ceramics were fabricated by spark plasma sintering at 1173-1323 K. Apart from the host ZnO phase with a wurtzite structure, a trace of ZnAl 2 O 4 secondary phase was segregated at the grain boundary and showed an increasing trend with sintering temperature. The largest power factor was achieved at 823 K in the sample sintered at 1223 K, which was 4·01×10 −4 W m −1 K −2 . The thermal conductivity decreased significantly owing to the phonon scattering via refined grains and dispersed ZnAl 2 O 4 phase and reached a low value of 2·42 W m −1 K −1 for the Zn 0·96 Al 0·04 O sample sintered at 1173 K, which has a maximum ZT value of 0·11 at 773 K.
ISSN:1432-8917
1433-075X
DOI:10.1179/1432891714Z.000000000653