KJ Ceramics 31

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Detailed Program

Paper Number : TE-I02

Time Frame : 11:10~11:35

Presentation Date : Thurseday, 27, November

Session Name : Thermoelectrics

Session Chair 1# : Soonil Lee

Session Chair 2# : Yashiaki Kinemuchi

Thermoelectric properties of thick film elements fabricated by aerosol deposition method

Yuichi NAKAMURA

Toyohashi University of Technology

Thermoelectric conversion is a promising method to harvest thermal energy even from small heat source. Among the thermoelectric materials, the thermoelectric oxides such as Ca3Co4O9 (Co349) and CaMnO3 (Mn113) are expected to be used at high temperature up to 1000 K. For the actual application, -type modules are widely used. Recently, the monolithic multilayer type structures, in which the p- and n-type thick layers were stacked with insulators between them, are proposed for their advantage of small size, high packing density, and high reliability [1]. The aerosol deposition (AD) method is a promising technique to prepare high density ceramic thick film by ejecting aerosol consisting of a mixture of fine ceramic particles and gas from the nozzle to the substrate [2-3]. We reported that Co349 thick films fabricated by AD method showed thermoelectric properties as high as the conventional hot pressed bulk after short annealing at 900 °C for 1h [3]. This suggests that the AD process is effective to fabricate thermoelectric thick films. In this work, the Co349/Mn113 thermoelectric thick film elements were fabricated by AD method, and the thermoelectric properties of the elements were evaluated. The Co349 and Mn113 powders with the composition of 10% Bi substituted for Ca site were prepared. The Mn113 films deposited by AD method were annealed at 900~1100 °C for 1h to improve crystallinity, and their properties were shown in Figure 1 with those of bulk sample. The AD films showed the Seebeck coefficient and electrical conductivity as high as those of bulk sample irrespective of low temperature and short annealing time due to high density of as deposited film. Figure 2 shows the output voltage and generated power properties of the one pair Co349/MgO/Mn113 thermoelectric layered element formed by AD method. The voltage decreased linearly as increasing current, and the output power showed the maximum. Although the output power was not enough high due to the small temperature difference and thin thickness, this property was as high as expected from the properties of Co349 and Mn113 single films. This means that the high density films fabricated by AD method is effective to form thermoelectric monolithic module.

References:

[1] S. Funahashi, T. Nakamura, K. Kageyama, H. Ieki, J. Appl. Phys. 109 (2011) 124509.
[2] J. Akedo, M. Lebedev, Jpn. J. Appl. Phys. 38 (1999) 5397.
[3] Y. Nakamura, Y. Matsufuji, M. Inoue, J. Phys.: Conf. Series 352 (2012) 012026.

Acknowledgements :

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