Sb掺杂Mg2-xZnxSi固溶体的热电性能

Thermoelectric Performance of Sb-doped Mg2-xZnxSi solid solutions

摘要:

利用B2O3助熔剂法结合SPS技术制备了Mg2-xZnxSi0.99Sb0.01(0 ≤ x ≤ 0.1)固溶体。测量了300 K - 780 K温度区间内试样的电导率、塞贝克系数和热导率。发现晶格热导率随Zn取代量的增大而降低。而电导率随Zn取代量的增大而先降低后增大。讨论了影响电导率与晶格热导率的变化规律的具体内在机制。所有样品中x=0.075样品的功率影子最高，在780 K达到1.76 mWm-1K-2，比基体Mg2Si0.99Sb0.01高约18%。x=0.1样品具有最低的晶格热导率，在770 K达到2.86 Wm-1K-1。低晶格热导率使Mg1.9Zn0.1Si0.99Sb0.01具有最高热电优值，在780 K达到0.37。

Abstract:

Mg2-xZnxSi0.99Sb0.01(0 ≤ x ≤ 0.1) solid solutions were prepared by B2O3 flux method combined with spark plasma sintering (SPS) technique. The electrical conductivity, Seebeck coefficient and thermal conductivity have been measured as a function of temperature from 300 K to 780 K. The lattice thermal conductivity reduces upon Zn substitution, however, the electrical conductivity first decreases and then increases with Zn content increasing. The underlying mechanism was discussed. Among the samples, the maximum PF of 1.76 mWm-1K-2 at x=0.075 was obtained at 780 K, about 18% higher than that of Mg2Si0.99Sb0.01.The lowest lattice thermal conductivity of 2.86 Wm-1K-1 is obtained at 770 K for the x=0.1 sample. As a result, a maximum dimensionless figure of merit of 0.37 was obtained for Mg1.9Zn0.1Si0.99Sb0.01 at 780 K .