Consolidation and thermoelectric properties of n-type bismuth telluride based materials by mechanical alloying and hot pressing

Bismuth telluride based n-type thermoelectric materials were prepared via the route of mechanical alloying (MA) and subsequent hot pressing (HP) process. Influence of hot press process parameters on the thermoelectric properties was investigated. Increasing hot pressing temperature from 340 to 400 °C, the figure of merit of the hot pressed sample increases rapidly, and then it grows slowly and no improvement is obtained when further increasing from 460 to 500 °C. Prolonging hot pressing time appropriately is helpful to improve thermoelectric properties, a maximum figure of merit of 1.7 × 10−3 K−1 has been obtained for the 4 h HP-ed sample.