The effect of short carbon fibers on the thermoelectric and mechanical properties of p-type CeFe4Sb12 skutterudite composites

Short carbon fiber-reinforced p-type skutterudite CeFe4Sb12 composites were fabricated by a melting-annealing process combined with spark plasma sintering, the effect of carbon fibers on the thermoelectric and mechanical properties were investigated, and the relationship between the microstructure and the mechanical properties of the composites were elucidated. The results indicate that the carbon fibers were well distributed throughout the matrix and were in intimate contact with the CeFe4Sb12 grains without interlayers. Both the flexural strength and the fracture toughness of CeFe4Sb12 were enhanced with the addition of the carbon fibers. Considering the tradeoff between the thermoelectric and mechanical properties, the optimal carbon fiber content was found to be 1 vol.%. The flexural strength of the composite containing 1 vol.% fiber was improved by 53%, whereas the fracture toughness and ZT value remained nearly unchanged.