The SEM images in Fig. 2 reveal that the addition of PCN
resulted in significant changes in the microstructure of the
ceramics. Some grains are observed to have irregular shapes
with both open and close pores as a result of the high rate of
the evaporation of PbO during the sintering.
17)
The images
also show that the grain size of the ceramics varied
considerably from 0.43 to 19.56mm(Table I). However,
the average grain size significantly decreased with an
increase in the content of PCN. It can also be seen that
the maximum density is obtained in the 0.7PZT–0.3PCN
ceramics, while the minimum density is observed in the
0.5PZT–0.5PCN ceramics. Interestingly, the density results
can be correlated to the microstructure because high-density
0.7PZT–0.3PCN ceramics show high degrees of grain close
packing, whereas low-density 0.5PZT–0.5PCN ceramics
contain many closed pores.