ICT2014 Abstracts

Development of low cost thermoelectric materials is the key to future mass production of thermoelectric generators. In recent years, MnSi_1.73 (HMS) has been shown to be a highly efficient thermoelectric material although not yet archiving state of the art figure of merit. The addition of excess silicon has been shown to be beneficial for the thermoelectric properties of HMS reaching a ZT of about 0.63 at 450°C. Iron is a known alloying element in the HMS system which reduces of charge carrier concentration. Iron was added in specific amounts in order to keep the chiminey ladder phase while excess silicon was added to prevent the formation of any secondary MnSi phase and to retain a nearly uni-phase HMS matrix. The following samples were explored: (Mn_0.95Fe_0.05)₁₁Si₁₉ + 4.29% Si, (Mn_0.9Fe_0.1)₇Si₁₂+ 4.29% Si, (Mn_0.8Fe_0.2)₂₃Si₃₉ + 4.29% Si, (Mn_0.7Fe_0.3)₂₂Si₃₇ + 4.29% Si. All of the compositions were measured for their thermoelectric properties along with their metallurgical properties in order to evaluate their merits.  The behavior of the (Mn_0.7Fe_0.3)₂₂Si₃₇ specimen changed to an n-type behavior as opposed to all the other specimens.