Fig. 2 shows the median diameter, BET surface area, and
particle size distributions of the CSed powders before and after
ball milling. Given that many agglomerations were formed
during the high temperature combustion synthesis, the particle
size distribution showed two obvious peaks with a median
diameter D50 of 41.75 μm before the ball milling. After 0.5 h
ball milling, the particle size moved to the left and the D50
decreased to 1.25 μm. BET surface area increased from 3.0 m2
/
g to 6.26 m2
/g with the increasing of ball milling time to 20 h.
However, the range of the particle distribution increased along