In this study, $FeSi_2$ as high temperature performance capable thermoelectric materials was manufactured by powder metallurgy.The as-casted Fe-Si alloy was annealed for homogenization below $1200^{circ}C$ 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 ($1200^{circ}C$, 12 h). In order to precipitate ${eta}-FeSi_2$, heat treatment was performed at $850^{circ}C$ with varying dwell time (7, 15 and 55 h). As a result of this experiment thermoelectric phase ${eta}-FeSi_2$ was quickly transformed by powder metallurgical process. There was not much change in powder factor between 7h and 55h specimens.