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采用放电等离子烧结(SPS)技术在800～1000K温度范围内,原位反应合成了以Ce,La作为填充原子及Ni,Fe作为置换原子的填充式方钴矿化合物REy(Fe/Ni)xCo4-xSb12(x=0～1.0,y=0～0.4)。系统研究了填充原子的种类、填充方式以及置换原子的种类对晶格热导率及热电性能的影响。结果表明,在Co位置上Fe或Ni的置换,能显著降低其晶格热导率,与Fe相比,Ni对晶格热导率的影响更显著。在Skutterudite结构Sb组成的二十面体空洞填充Ce,La原子可以显著降低其晶格热导率,在填充分数相同时,两种稀土原子复合填充较单一原子填充更能有效降低晶格热导率。电导率随Ce,La填充分数的增加而降低,Seebeck系数随填充分数的增加而升高。填充分数为0.3的Ce0.1La0.2FeCo3Sb12化合物具有最低的晶格热导率和最大的ZT值,在800K时达0.6左右。
In this paper, the solid-state reaction of REy (Fe / Ni) x Co4-SnO3 with Fe and Ce as filling atoms and Ni and Fe as replacement atoms was synthesized by spark plasma sintering (SPS) xSb12 (x = 0 to 1.0, y = 0 to 0.4). The influence of the type of filling atoms, the filling method and the types of atoms on the lattice thermal conductivity and the thermoelectric properties were studied systematically. The results show that substitution of Fe or Ni at the Co site can significantly reduce the lattice thermal conductivity, and the effect of Ni on the lattice thermal conductivity is more pronounced than that of Fe. Ce and La atoms filled with icosahedron composed of Sb in Skutterudite structure can significantly reduce the lattice thermal conductivity. When the filling fraction is the same, the recombination of two rare earth atoms is more effective than the single atomic filling in reducing the lattice thermal conductivity . The conductivity decreases with the increase of Ce and La filling fraction, Seebeck coefficient increases with the increase of filling fraction. The Ce0.1La0.2FeCo3Sb12 compound with a fill fraction of 0.3 has the lowest lattice thermal conductivity and the largest ZT value, reaching around 0.6 at 800K.