Low-temperature preparation and thermoelectric properties of CrSi₂, MnSi_1.7+δ, and CoSi using a Na flux

Powders of transition metal silicides, CrSi₂, MnSi_1.7+δ, and CoSi, were prepared by heating powder mixtures of Cr, Mn, and Co metals and Si with a Na flux at 773-823 K for 12 h. The grains of the prepared metal silicide powders were composed of primary particles with sizes smaller than those of the source powders of the metals and Si. The bulk samples prepared by sintering the metal silicide powders were characterized. Maximum ZT values of 0.10, 0.42, and 0.13 were obtained for the samples of CrSi₂ at 873 K, MnSi_1.7+δ at 773 K, and CoSi at 623 K, respectively.