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利用B2O3助熔剂法结合热压法制备了Mg2Si0.487-2x Sn0.5(Ga Sb)x Sb0.013(0.04≤x≤0.10)固溶体。X射线衍射结果表明样品呈单相。Sb掺杂有效提高了样品的电导率。随温度升高,Mg2Si0.487-2x Sn0.5(Ga Sb)x Sb0.013(0.04≤x≤0.10)样品的电导率降低而塞贝克系数升高。随Ga Sb含量的增多,样品的电导率呈现出先增大后减小的变化趋势。所有样品中Mg2Si0.287Sn0.5(Ga Sb)0.1Sb0.013具有最低晶格热导率,其室温晶格热导率比Mg2Si0.5Sn0.5[11]低15%。由于电导率较高使Mg2Si0.327Sn0.5(Ga Sb)0.08Sb0.013具有最高热电优值,在720 K达到0.61,显著高于基体Mg2Si0.5Sn0.5[11]的最高热电优值0.019。
The solid solution of Mg2Si0.487-2x Sn0.5 (Ga Sb) x Sb0.013 (0.04≤x≤0.10) was prepared by B2O3 flux method and hot pressing method. X-ray diffraction results showed that the sample was single phase. Sb doping effectively increases the conductivity of the sample. With the increase of temperature, the electrical conductivity of Mg2Si0.487-2x Sn0.5 (Ga Sb) x Sb0.013 (0.04≤x≤0.10) samples decreases and the Seebeck coefficient increases. With the increase of the content of Ga Sb, the conductivity of the sample shows the trend of first increasing and then decreasing. In all the samples, Mg2Si0.287Sn0.5 (GaSb) 0.1Sb0.013 has the lowest lattice thermal conductivity, and its lattice thermal conductivity at room temperature is 15% lower than that of Mg2Si0.5Sn0.5 [11]. Due to the higher conductivity, Mg2Si0.327Sn0.5 (Ga Sb) 0.08Sb0.013 has the highest thermoelectric figure of merit, reaching 0.61 at 720 K, which is significantly higher than the highest pyroelectric 0.019 of the matrix Mg2Si0.5Sn0.5 [11].