Preparation and Thermoelectric Properties of (Mg_2Si_(1-x)Sb_x)_(0.4)-(Mg_2Sn)_(0.6) Alloys

n-type(Mg2Si1-xSbx)0.4-(Mg2Sn)0.6(0≤x≤0.0625) alloys were prepared by an induction melting and spark plasma sintering method using bulks of Mn,Si,Sn,Sb as raw materials.The analyzing results of the structure and thermoelectric properties show that the single-phase(Mg2Si1-xSbx)0.4-(Mg2Sn)0.6 alloys can be obtained at 8wt% excess of Mg addition.The lattice constant increases linearly with the amount of Sb,the electrical resistivity ρ firstly increases and then decreases.The electrical resistivity ρ of samples(x≤0.025) shows semi-conductor behavior,while that of the samples(x0.025) shows the metallic behavior.The Seebeck coefficient α firstly increases and then decreases with the increase of x value.Compared with the non-doped sample,the thermal conductivity κ for samples(x ≤ 0.025) decreases and that of the other samples(x0.025) increases.The ZT value for(Mg2Si0.95Sb0.05)0.4-(Mg2Sn)0.6 sample reaches its highest value of 1.22 at 773 K,which is much higher than that of the non-doped sample.