Enhanced thermoelectric figure of merit in nano-structured Si dispersed higher manganese silicide
Idioma
en
Article de revue
Este ítem está publicado en
Materials Science in Semiconductor Processing. 2019-12, vol. 104, p. 104649 (9 p.)
Elsevier
Resumen en inglés
Higher manganese silicide (HMS) is considered as a promising thermoelectric material at intermediate temperatures. Samples of Si-rich HMS were prepared by arc melting followed by ball milling combined with densification ...Leer más >
Higher manganese silicide (HMS) is considered as a promising thermoelectric material at intermediate temperatures. Samples of Si-rich HMS were prepared by arc melting followed by ball milling combined with densification by an induction hot uni-axial pressing (HP) and spark plasma sintering (SPS), respectively. Powder X-ray diffraction, SEM and EPMA studies confirmed the presence of Si in HMS matrix. TEM micrographs on milled powders further confirmed the presence of Si particles with an average size of ~5–10 nm in HMS matrix. Microstructure investigations on densified samples revealed that SPS process seems to be a beneficial tool for embedding the nanostructures of Si (~20–50 nm) particles in HMS matrix. SPS also controls the grain growth of HMS during densification, which in turn reduces the total thermal conductivity from ~4.4 W/m.K to 2.10 W/m.K. On the other hand, samples processed by HP showed the value of ~2.44 W/m.K with similar sintering parameters as in SPS used for densification. Huge reduction in lattice thermal conductivity of about ~55%, and a considerable increase in Seebeck value was observed in Si-rich BMed HMS. However, reduction in electrical conductivity associated with insulating Si particles in HMS matrix limited the zT to ~0.26 at 725 K.< Leer menos
Palabras clave en inglés
Thermoelectric properties
Mechanical alloying
Higher manganese silicides
Spark plasma sintering
Hot uni-axial pressing
Orígen
Importado de HalCentros de investigación