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Application of SiC‐Si functionally gradient material to thermoelectric energy conversion device
Author(s) -
Okano Kazuo,
Takagi Yoshimitsu
Publication year - 1996
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/eej.4391170602
Subject(s) - materials science , thermoelectric effect , temperature gradient , energy transformation , engineering physics , energy (signal processing) , optoelectronics , silicon carbide , thermoelectric materials , composite material , thermal conductivity , engineering , physics , thermodynamics , quantum mechanics
Because of its high–temperature chemical stability, SiC ceramic is a promising material for high‐temperature device applications such as thermoelectric energy converters. However, the electrical conductivity of SiC ceramic is too low for it to be used as a thermoelectric energy converter at the cold junction. Therefore, we propose a SiC‐Si functionally gradient material (FGM) in order to improve the electrical conductivity of the SiC ceramic at the cold junction. An SiC rod was fired in a temperature gradient furnace. One end of the SiC rod was maintained at 2473 K and the other end was maintained at 1973 K for 30 min. After firing, the porous SiC edge fired at 1973 K was dipped into molten Si in order to infiltrate molten Si into the porous SiC. The microstructure of the FGM is classified into three regions: the SiC‐Si composite material; the porous SiC ceramic; and the densified SiC ceramic. The electrical conductivity, the Seebeck coefficient and the thermal conductivity for each region of SiC‐Si FGM was measured at 300 K; a figure of merit was calculated. The figure of merit of the SiC‐Si FGM at the cold junction, at room temperature, was 10 8 times higher than that of a nongradient SiC ceramic.