few small aggregates. In order to estimate the average grain
size, Image J software was used to measure the individual
particles (n[300). Most of the particles measured were in
the range of 100–400 nm while the average particle size is
estimated as 230 ± 30 nm. The wide distribution in the
primary particle size is due to different impact of ballmilling
process. Detailed chemical composition analysis,
performed by coupled EDX, results showed the presence of
excessive Mg, O, and Si elements; which supports the XRD
results in that the MgO and free Si phases are present in the
ball-milled Mg2Si powder.
Figure 2b–h show the detailed microstructural analyses
from the fractured surfaces of SPS samples compacted
under various conditions. Figure 2b shows the internal
structures of the grains when BM Mg2Si was compacted at
650 C at a holding time of 5 min. The density calculation
shows (See, Table 1) a low compaction density and the
fractured surface microstructure contains portions of pores/
voids (Fig. 2b). In Fig. 2c, d micrographs from the SPS
samples at 750 and 850 C with 5 min holding time are
presented, which show less porosity and more evenly distributed
grain growth. The compaction density results,
Fig.