Rishikesh Kumar; Saravanan Muthiah; Avinash K. Singh; Ajay Dhar
Abstract
We report the synthesis of both n-type Mg2Si and p-type MnSi1.73 using reaction sintering employing spark plasma sintering (SPS) process. The thermoelectric device was fabricated using these synthesized thermoelectric materials having a ZT value of ~ 0.7 for n-type Mg2Si and ~ 0.55 for p-type MnSi1.73. ...
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We report the synthesis of both n-type Mg2Si and p-type MnSi1.73 using reaction sintering employing spark plasma sintering (SPS) process. The thermoelectric device was fabricated using these synthesized thermoelectric materials having a ZT value of ~ 0.7 for n-type Mg2Si and ~ 0.55 for p-type MnSi1.73. The two design combination of unicouple thermoelectric devices were fabricated; nickel contacts at hot & cold ends in first device and graphite contact at hot end & nickel contact at cold end in another device. The device comprised of n-type Mg2Si & p-type MnSi1.73 legs each with dimensions of 4 × 4 × 10 mm. The voltage and current output characteristics of this thermoelectric device were evaluated at temperature gradient between hot and cold ends in the range of 50 to 350 K. The maximum open circuit voltage output (~135mV) and maximum current output (~200 mA) from nickel contacts device were obtained at ?T ≈350 K, which would be much higher at elevated operating temperatures and employing several such thermoelectric couples.
Sandeep K. Pundir; Sukhvir Singh; B. Sivaiah; Rajesh Kumar; Ajay Dhar
Abstract
Thermoelectric properties of n-type bismuth telluride and its nanocomposite reinforced with different concentration of multi wall carbon nanotubes (MWCNTs) are reported. Nanocomposites of bismuth telluride with MWCNTs were synthesized by using high energy ball milling followed by spark plasma sintering ...
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Thermoelectric properties of n-type bismuth telluride and its nanocomposite reinforced with different concentration of multi wall carbon nanotubes (MWCNTs) are reported. Nanocomposites of bismuth telluride with MWCNTs were synthesized by using high energy ball milling followed by spark plasma sintering (SPS). MWCNTs reinforced nanocomposites of bismuth telluride resulted improvement in its figure of merit ZT from 0.76 (for Bi2Te3) to 0.85 (for Bi2Te3 + 2%MWCNTs) at 473K temperature. Thermoelectric parameters of nanocomposites of Bi2Te3 were characterized by Laser Flash Technique. The improvements found in ZT value may be due to decrease in thermal conductivity of the nanocomposites. Concentration of MWCNTs in bismuth telluride leads to dampening the phonon propagation with addition to the interface scattering of phonons from phase boundaries as well as grain boundaries which leads to decrease in thermal conductivity.