High thermoelectric performance of higher manganese silicides prepared by ultra-fast thermal explosion

摘要

Higher manganese silicide (HMS) is an environmentally friendly p-type thermoelectric material with attractive performance and high stability in the intermediate temperature range (500-800 K). Due to the high melting point of HMS, the preparation methods reported previously always contain energy-intensive processes requiring long preparation periods and high cost. In this study, thermal explosion (TE) was adopted for a facile preparation of high performance HMS via a low cost route. During a typical thermal explosion (TE) process, nanostructured polycrystalline single-phase HMS powder with excellent thermoelectric performance is obtained in an ultra-short period of time (about 10 min). Dense bulk samples are then prepared by a rapid plasma activated sintering (PAS) technique. With Ge substituted in Si sites, a significant increase can be observed, which further enhanced the electrical properties. The results show that the Ge doped sample Mn(Ge0.015Si0.985)(1.75) prepared via the TE-PAS technique exhibits a maximum ZT of 0.62 at 840 K, which demonstrates that the TE-PAS technique is a versatile route for rapid fabrication of HMS and other thermoelectric materials.