It was claimed by simulation in Zaitsev
et al. [19], that this type of TE materials can attain greater ZT
values because of high charge mobilities, containing large
effective masses and comparatively low lattice component of
thermal conductivity. For the past decades, this class of
materials has been under investigation for mid-to-high temperature
range of TE applications. Ball-milling technique is a
well-known method for brittle material production; but the
ductile characteristics and reactivity ofMgwith oxygenmake
this synthesis process a nontrivial route. [20].
There are, however, few reports on the synthesis parameters
and improved ball-milling methods to manufacture
nanocrytallineMg2Si powder [20–22].However optimization
of sintering parameters is required to obtain ideal densification
and microstructure. In this work, nanocrystalline Mg2Si
materials were prepared by ball-milling process and spark
plasma sintering (SPS) process was used for consolidation. In
particular, SPS consolidation parameters were investigated to
achieve the highest compaction density and conserve the
nanostructured grains in the sintered pellets, by studying different
temperature and holding time for SPS experiments.
Crystallite size and crystalline phase identification were performed
by XRD, SEM, and TEM techniques; detailed
microstructure analyses from the fractured surfaces of compacts
are presented.