Kr. Han et al., Preparation method of submicrometer-sized alpha-alumina by surface modification of gamma-alumina with alumina sol, J AM CERAM, 83(4), 2000, pp. 750-754
A method is introduced to prepare almost-spherical submicrometer-sized or-a
lumina via surface modification of gamma-alumina with an alumina sol, Mille
d gamma-alumina, in the presence of 3 wt% of alpha-alumina with a median pa
rticle size (d(50)) of 0.32 mu m (AKP-30), produced irregularly shaped alph
a-alumina with d(50) approximate to 0.3 mu m after heat treatment at 1100 d
egrees C for 1 h. gamma-alumina that had been surface-modified by milling i
n the presence of 3 wt% of the alumina sol resulted in almost-monosized, sp
herical a-alumina similar to 0.3 mu m in size after heat treatment at 1100
degrees C for 1 h, Furthermore, almost-spherical or-alumina 0.1-0.2 mu m in
size was obtained by milling gamma-alumina with 3 wt% of AKP-30 alumina in
the presence of 3 wt% of the alumina sol, followed by heat treatment at 11
00 degrees C for 1 h, The alumina sol that has been introduced in this work
seems to act as a dispersant, in addition to helping to form a spherical s
hape.