Thermoelectric properties of p-type Si-rich higher manganese silicide for mid-temperature applications

High density pellets of MnSi1.74, MnSi1.8 and MnSi1.9 were prepared by an induction-melting and a rapid induction hot-pressing. Presence of fine precipitations of metallic MnSi in MnSi1.74 and Si in both MnSi1.8 and MnSi1.9 were confirmed by means of X-ray diffraction, SEM and EDS analysis. With subsequent increase in Si content in HMS, the electrical conductivity gradually decreases and Seebeck coefficient significantly increases. Further, the total thermal conductivity was notably reduced to -2.1 W/mK at 725 K for MnSi1.8 which resulted in the enhanced zT of -0.35 at 773 K.

Automated summary

High density pellets of MnSi1.74, MnSi1.8 and MnSi1.9 were prepared by induction-melting and rapid induction hot-pressing. XRD, SEM, and EDS analyses confirmed the presence of fine precipitations of metallic MnSi in MnSi1.74 and Si in MnSi1.8 and MnSi1.9. The increase in Si content led to gradual decrease in electrical conductivity and significant increase in Seebeck coefficient, with notable reduction in total thermal conductivity for MnSi1.8 resulting in enhanced zT at high temperatures.