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Author: search.filters.author.Neeyakorn, Worakarn

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    Preparation, characterization and finite element computation of Cu(Al 1/2Fe1/2)O2 Delafossite-oxide themoelectric generator module
    (2014-09-02)
    Ruttanapun, Chesta
    ;
    Jindajitawat, Phumin
    ;
    Buranasiri, Prathan
    ;
    Naenkieng, Daengdesh
    ;
    Boonyopakorn, Narongchai
    The CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> delafossite oxide has been synthesized by solid state reaction method for studying thermoelectric properties and measuring thermoelectric generator output electric power. The Finite Element technique was used to compute the output voltage of thermoelectric generator in applying temperature difference on a single bar and a module model with compared to the measurement results. The measurement results of positive sign Seebeck coefficient confirm the p-type conductor of the sample. The properties of Seebeck coefficient, electrical conductivity, and thermal conductivity are range from 260 to 310V/K, from 7 to16 S/cm and from 2.5 to 3.5 W/cm-K,respectively, in the temperature range of 300 to 960 K. The output voltage of the single bar in dimension 4.2 × 2.5 × 20 mm <sup>3</sup> obtained 0.5 to 3 mV on applying temperature difference from 1 to 10 K closely to the Finite Element result. The computing results of the thermoelectric single bar and module in high temperature reveal the output electric voltage of CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> oxide raises with the temperature and the number of thermoelectric leg increase. In important results, the high value of electric voltage is obtained 0.2 and 0.4 V for the single bar and the module at 950 K. © 2014 Taylor & Francis Group, LLC.
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    High temperature thermoelectric properties of delafossite CuBO2
    (2014-01-01)
    Ruttanapun, Chesta
    ;
    Jindajitawat, Phumin
    ;
    Buranasiri, Prathan
    ;
    Thowladda, Warawoot
    ;
    Neeyakorn, Worakarn
    CuBO<inf>2</inf> is prepared by a solid-state reaction method to investigate thermoelectric properties in high temperature. The XRD result confirms the CuBO<inf>2</inf> compound existing in this method. The Seebeck reveals the compound displays p-type thermoelectric material. The experimental results of electrical resistivity exhibited results of 0.004 S/cm to 0.038 S/cm with the temperature range of 650 to 830 K. The Seebeck value is in the range of 450 μV/K to 950 μV/K, and the thermal conductivity is in the range of 1.4 × 10<sup>-5</sup> to 5.3 × 10<sup>-5</sup> W/m-K<sup>2</sup> with the same temperature. The maximum PF and ZT is 5.3 × 10<sup>-5</sup> W/m-K<sup>2</sup> and 0.0016, respectively, at 960 K. This work demonstrates that the CuBO<inf>2</inf> delafossite-oxide compound displays the p-type thermoelectric materials. © 2014 IEEE.
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    Reinvestigation thermoelectric properties of CuAlO2
    (2014-01-01)
    Ruttanapun, Chesta
    ;
    Kosalwat, Wattana
    ;
    Rudradawong, Chalermpol
    ;
    Jindajitawat, Phumin
    ;
    Buranasiri, Prathan
    Bulk CuAlO2 delafossite has been synthesized by solid state reaction to reinvestigate the thermoelectric properties. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured in a high temperature range of 300 to 960 K. The result of positive sign of Seebeck coefficient confirms p-type nature of CuAlO2 compund. The results of bulk sample for Seebeck coefficient, the electrical conductivity and thermal conductivity are range of 900 to 300 μV/K, of 0.01 to 2 S/cm, and of 3.5 W/mK to 1.5 W/mK. The maximum ZT value of bulk sample is 0.017 at a 960 K. These results can be concluded that the bulk CuAlO2 by solid state state displays thermoelelctric material.
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    Thermoelectric properties of Sn2+-substituted CuFeO2 delafossite-oxide
    (2013-10-29)
    Ruttanapun, Chesta
    ;
    Jindajitawat, Phumin
    ;
    Thowladda, Warawoot
    ;
    Neeyakorn, Worakarn
    ;
    Thanachayanont, Chanchana
    This study aims to investigate the effect of the Sn<sup>2+</sup>-substituted into the CuFeO<inf>2</inf> delafossite on thermoelectric properties in the Sn content of x = 0.03, 0.05. The CuFe<inf>1-x</inf>Sn<inf>x</inf>O<inf>2</inf> samples were synthesized by solid state reaction. The crystal structure was characterized by XRD, TGA, XPS and the thermoelectric properties were measured in the range of 300 to 960 K. The Seebeck coefficient display positive sign in all temperature range and the XPS show the stable Sn<sup>+2</sup> state as confirming the Sn-doped CuFeO<inf>2</inf> playing p-type conductor. The Sn<sup>2+</sup>-substituted supports the mixed valency Fe<sup>3+</sup>/Fe<sup>4+</sup> state in transition octahedral oxide of FeO<inf>6</inf> layer enhancing Seebeck coefficient. The high Seebeck are appeared in content of x=0.03 which are 280 to 340 μV/K in the range of 300 to 800 K. The experimental Seebeck corresponds to the prediction formula at high temperature. Totally, the maximum Power Factor is 2.30×10<sup>-4</sup> W/mK<sup>2</sup> occurring in the CuFe<inf>0.95</inf>Sn<inf>0.05</inf>O<inf>2</inf> at 860 K which is higher than that value of the undoped-CuFeO<inf>2</inf> in 4 times. These support that the Sn-substituted CuFeO<inf>2</inf> delafossite enhancing thermoelectric properties. © (2013) Trans Tech Publications, Switzerland.