The
fig. 7 showed the DSC curves of samples with different
amount of a-Al2O3 seed at a temperature in the range from 600 C
to 1000 C. From the curves, we can
find that the four samples have
the same endothermic peak and exothermic peak, which indicated
that the seeds has no effects on the decomposition temperature of
amorphous aluminum hydroxide to g-Al2O3 and the transformation
temperature of g-Al2O3 to a-Al2O3. The XRD analysis in Fig. 8
showed that the sample Al-3 and sample Al-7 calcined at 1000 C
for different time. As show in Fig. 8, with the increasing of calcining
time, the diffraction peaks of g-Al2O3 became weaker. The sample
Al-7 with 3.5% seed showed the pure diffraction peaks of a-Al2O3
when calcined at 1000 C for 1.5 h, While, the sample Al-3 without
seed showed the diffraction peaks of g-Al2O3 when calcined at
1000 C for 2.5 h. Although the addictive of seed has no impact on