Abstract Recently magnesium silicide (Mg2Si) has
received great interest from thermoelectric (TE) society
because of its non-toxicity, environmental friendliness,
comparatively high abundance, and low production material
cost as compared to other TE systems. It also exhibited
promising transport properties, including high electrical
conductivity and low thermal conductivity, which
improved the overall TE performance (ZT). In this work,
Mg2Si powder was obtained through high energy ball
milling under inert atmosphere, starting from commercial
magnesium silicide pieces (99.99 %, Alfa Aesar). To
maintain fine microstructure of the powder, spark plasma
sintering (SPS) process has been used for consolidation.
The Mg2Si powder was filled in a graphite die to perform
SPS and the influence of process parameters as temperature,
heating rate, holding time and applied pressure on the
microstructure, and densification of compacts were studied
in detail. The aim of this study is to optimize SPS consolidation
parameters for Mg2Si powder to achieve high
density of compacts while maintaining the nanostructure.
X-Ray diffraction (XRD) was utilized to investigate the
crystalline phase of compacted samples and scanning and
transmission electron microscopy (SEM & TEM) coupled
with Energy-Dispersive X-ray Analysis (EDX) was used to
evaluate the detailed microstructural and chemical composition,
respectively. All sintered samples showed compaction
density up to 98 %. Temperature dependent TE
characteristics of SPS compacted Mg2Si as thermal conductivity,
electrical resistivity, and Seebeck coefficient
were measured over the temperature range of RT 600 C
for samples processed at 750 C, reaching a final ZT of
0.14 at 600 C.