It is interesting to note that the
average particle size remained almost constant and only varied
between 41 m and 45m(Fig. 2a and b). The particle morphology
is close to spherical. The shape factors of these two samples
are 0.89 and 0.87, respectively. Further microstructural examination
indicates that there was no entrapped gas in all the RDC
samples, and only very fine shrinkage pores can be observed