Work

Effect of spark plasma sintering (SPS) on the thermoelectric properties of magnesium ferrite

Year: 2016

Type: article

Abstract: Magnesium ferrite MgFe 2 O 4 was synthesized with two different methods, spark plasma sintering (SPS) and conventional solid-state reaction sintering (SSRS), and thermoelectric properties were investigated. SPS processing was found to yield two attractive features: SPS at 900 °C enabled retaining the submicron particle size of 0.3–0.5 µm from ball-milling, leading to lower thermal conductivity, 3 W/mK@300 K. 1200 °C SPS sintering led to the same sample grain size of 1.0–3.0 µm as SSRS, but still exhibited significantly lower thermal conductivity of 4.3 W/mK@300 K compared to the SSRS sample with 14 W/mK@300 K, which exhibited neck formation between particles. Furthermore, while the finer microstructuring led to a reduction in the thermal conductivity, the resistivity of SPS MgFe 2 O 4 showed little dependence on the particle size at expected thermoelectric working temperatures above 523 K, which indicates success to some degree of phonon selective scattering due to differences in mean-free-paths of electrons and phonons. As a process, SPS samples are found to exhibit four- to sevenfold enhancement of ZT compared to the conventional SSRS sample. While the maximum ZT in the present samples is relatively low, taking a value of 0.07 for the SPS 1200 °C sintered sample, the processing insights may be utilized for similar systems.

Source: Materials for Renewable and Sustainable Energy

DOI: 10.1007/s40243-016-0086-9

Authors: Ryosuke S. S. Maki, Seiji Mitani, Takao Mori

Institutions: University of Tsukuba, National Institute for Materials Science

Language: English

Topic: Advanced Thermoelectric Materials and Devices

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,190

Funders: Japan Science and Technology Agency, Core Research for Evolutional Science and Technology