Phase Transition and Thermoelectric Property of Ultra-Fine Structured β-FeSi2 Compounds
FeSi2 compounds were fabricated by rapid solidification and hot pressing, which is considered to be a mass production technique for this alloy. Structural behavior of melt-spun ribbon during heat-treatment and Seebeck coefficient of the hot pressed bulk were systemically investigated and compared with conventionally fabricated alloys. The melt-spun ribbon consists of α-Fe2Si5 and ε-FeSi phase. With increasing annealing time, the phase transition to β-FeSi2 phase occurred more rapidly. 20 min of annealing is sufficient for a homogeneous formation of β-FeSi2 phase in melt-spun ribbon, while it is 100 h in as-cast alloy. In this research, the formation mechanism of β-FeSi2 phase during annealing is a transition of α+ε→β. The microstructure of sintered bulk generally consist of a randomly distributed β-FeSi2 phase with an average grain size of 0.9 μm. The increase of Seebeck coefficient in melt-spun and sintered specimen is due to fine grain size formed by rapid solidification.
Jang Hyun Sung, Chan Gyu Lee, Yong Zoo You, Young Kook Lee and Jae Young Kim
S. J. Hong et al., "Phase Transition and Thermoelectric Property of Ultra-Fine Structured β-FeSi2 Compounds ", Solid State Phenomena, Vol. 118, pp. 591-596, 2006