Geoscience Reference
In-Depth Information
Figure 10.36 Dispersibility of nanoparticles: CoAl
2
O
4
(left); ZnO (center); Fe
2
O
3
(right) in
water.
DNA, which leads to the applications to new biotechnology or IT devices using
directed assembly of semiconductor nanoparticles.
10.6.8 Hydrothermal Preparation of Perovskite Type of
Mixed Oxide Ceramics
Alkaline earth titanates have always appeared in two types of stable phases: the
pyrochlore and the perovskite structural phases. Between these, the high-purity,
fine perovskite titanates with exact stoichiometry are widely used as ferroelectric
materials, owing to their excellent electric, pyroelectric, semiconducting, and
electro-optic properties. Hydrothermal processing is a very convenient technique
for the preparation of various multicomponent oxide materials that have maximum
utility in present-day electronics applications
[161
163]
. These multicomponent
oxides from electronic ceramic or catalytic applications can be produced by hydro-
thermal synthesis at moderate temperatures and pressures (
100
C and 0.1 MPa).
The success of hydrothermal synthesis depends on the selection of precursors that
are both reactive and cost-effective as well as appropriate process condition vari-
ables, which include temperature, pH, and reagent concentration
[4]
. From 2000
onwards, hundreds of publications have appeared in literature devoted to various
.
