Abstract :
Ba(Zr0.2Ti0.8)O3 (BZT) ceramics are prepared
from spray-dried powder by spark plasma sintering (SPS)
and by normal sintering. By the application of SPS,
ceramics with[96% relative densities could be obtained
by sintering at 1,100 C for 5 min in air atmosphere. The
pellet as sintered by SPS at 1,100 C was black and conductive.
Although SPS was carried out in air atmosphere,
the samples were deoxidized by heating the carbon die. By
post-annealing at 1,000 C for 12 h in air, the pellet was
oxidized and became white and insulating. Grain growth
was suppressed in the ceramics prepared by SPS, and the
average grain size was 0.52 lm. The starting powder
contained 1.90% carbon, mainly as binder, and the SPSprepared
ceramics and ordinary prepared ceramics contained
0.15 and 0.024% carbon, respectively. The BZT
ceramics obtained by SPS and the subsequent annealing at
1,000 C for 12 h exhibited a mild temperature dependence
of their dielectric constant. The field-induced displacement
of the BZT ceramics was less hysteretic and smaller than
that of the ceramics sintered by the conventional method.
