In this study, as high temperature performance capable thermoelectric materials was manufactured by powder metallurgy.The as-casted Fe-Si alloy was annealed for homogenization below for 3 h. Due to its high brittleness, the cast alloy transformed to fine powders by ball-milling, followed by subsequent compaction (hydraulic pressure; 2 GPa) and sintering (, 12 h). In order to precipitate , heat treatment was performed at with varying dwell time (7, 15 and 55 h). As a result of this experiment thermoelectric phase was quickly transformed by powder metallurgical process. There was not much change in powder factor between 7h and 55h specimens.