Enhanced thermoelectric and mechanical properties of p-type skutterudites with: In situ formed Fe₃Si nanoprecipitate

In the present work, p-type skutterudites La_0.8Ti_0.1Ga_0.1Fe₃CoSb₁₂ composite with n-type Fe₃Si nanoprecipitate was fabricated via an in situ method. Both thermoelectric and mechanical properties of La_0.8Ti_0.1Ga_0.1Fe₃CoSb₁₂/xFe₃Si composites were thoroughly investigated. With the introduction of homogeneously dispersed nanosized Fe₃Si in the matrix, the power factor is almost unchanged due to the counteraction between the decreased electrical conductivity and the significantly enhanced Seebeck coefficient. Simultaneously, the total thermal conductivity was decreased for samples with Fe₃Si nanoprecipitate because of the reduced electronic thermal conductivity. As a result, a ZT value of about 1.2 at 700 K has been achieved for La_0.8Ti_0.1Ga_0.1Fe₃CoSb₁₂/0.1Fe₃Si sample, whose ZT value was slightly enhanced in comparison with the Fe₃Si-freeLa_0.8Ti_0.1Ga_0.1Fe₃CoSb₁₂ sample. Furthermore, the indentation fracture toughness of La_0.8Ti_0.1Ga_0.1Fe₃CoSb₁₂/0.1Fe₃Si was improved by nearly 30% compared to the Fe₃Si-free skutterudites.