Simultaneous enhancement in thermoelectric performance and mechanical stability of p-type SiGe alloy doped with Boron prepared by mechanical alloying and spark plasma sintering

摘要

Silicon-Germanium (SiGe) based alloys are the promising and an attractive thermoelectric candidate for radioisotope thermoelectric generators (RTGs) at high temperature (>1000?°C) application. Intensive efforts are being made to enhance the thermoelectric properties and mechanical stability of p-type SiGe alloy. The current work reports on synthesis of SiGe alloy doped with Boron (B) with varying concentration (0.5–2.0?at.%) through mechanical alloying (MA) followed by spark plasma sintering (SPS). The synthesised SiGe alloy doped with B1.5at.% showcase the superior figure of merit (ZT) ? 0.525?at 800?°C which results in the significant enhancement of ～9.38% than the p-type RTG SiGe alloy. The synthesised SiGe alloys exhibit an improvised thermoelectric compatibility factor of 0.968?V-1(～16% higher than RTG SiGe alloy). The SiGeB1.5alloy demonstrated an ever-achieved physical robustness with the bench marked micro hardness of 9.93?±?0.12?GPa and fracture toughness (KIC) of 2.36?±?0.173?MPa√m (48% higher than SiGe alloy).