Conclusions
The n-type Mg2Si nanopowder was prepared by wet ballmilling
method and successfully used to fabricate highly
dense pellets using SPS. Detailed physicochemical characterization
results revealed that the as prepared powder
exhibited a crystallite size of 230 nm, reflecting the success of
nanostructuring attempts. Phase analysis revealed the presence
of secondary phases ofMgOand Si,which originate from
the raw material. Critical SPS process parameters as sintering
temperature and holding time were investigated to optimize
the consolidation parameters for the compaction of undoped
Mg2Si. We optimized the parameters to maintain the nanostructure
and achieve a high compaction density during the
SPS process. Based on the compaction density and grain size
evaluation, samples processed at 750 C were chosen for
further TE property evaluation. A ZT value *0.14 at 600 C
was obtained for SPS compacted sample at 750 C for 2 min
holding time—with grain size of in the range of 300–400 nm
and 97 % compaction density. It is suggested through further
optimization ofMg2Si nanopowder synthesiswith high purity
(the absence of oxide phases) and through doping, it is possible
that one can achieve a promising Mg2Si-based TE
material for power generation applications