Genomic Effects of the Quenching Process on the Microstructure and Thermoelectric Properties of Yb0.3Co4Sb12

This study systematically examines the traditional melting-quenching-annealing fabrication method for filled skutterudite Yb0.3Co4Sb12 to clarify which gene most influences the phase composition, microstructure, and thermoelectric properties of the final products. X-ray diffraction, electron energy dispersive spectroscopy, scanning electron microscopy, and thermoelectric measurements suggest that the Co-Sb peritectic segregation occurring during the quenching process-which can be inherited in the following ensuing fabrication process-shows a very important genomic effect on the microstructure evolution. Severe Co-Sb peritectic segregation would increase the diffusion paths of the composed elements (Yb, Co, and Sb) during the annealing process, making it significantly more difficult to form high-performance single filled skutterudites. The traditional fabrication process can be optimized by introducing a stirring step to accelerate the cooling rate, effectively suppressing the Co-Sb peritectic segregation and consequently improving thermoelectric performance; this result has been achieved in the large-scale Yb0.3Co4Sb12 sample. Our results suggest that the control of Co-Sb peritectic segregation is critical when developing the mass production process for filled skutterudites in the future.