Geoscience Reference
In-Depth Information
et al.
[87]
have studied the system Bi
2
O
3
a
H
2
O under hydrothermal con-
ditions and a part of the phase diagram is shown in
Figure 8.23
.
Muto and Taki
[88]
have synthesized potassium lithium hexatitanate
K
2
Li
2
Ti
6
O
14
crystals by the hydrothermal technique using TiO
2
and KOH
TiO
2
a
KF
a
LiOH.
The compound could be obtained in the following molar ratios: TiO
2
:LiOH:
KOH
1
1.5:1.0:7.5, and concentration of alkali 10 N, filling of solutions 35
50%,
5
400
C, time of run
T
70 h. The interesting feature is that potassium lithium
hexatitanate is not produced through the direct reaction of lithium ion with potas-
sium hexatitanate already formed.
The growth of rare earth titanates has not been reported in the literature so far by
the hydrothermal method, but there are some scanty reports by the flux method
[89]
.
Titanates, in general, show interesting physical properties like electrical, nonlin-
ear, dielectric, ferroelectric properties.
Figure 8.24
shows the Arrhenius plot log
$
$
σ
T
KF
80
70
60
50
40
Bi
12
TiO
20
30
Bi
4
Ti
3
O
12
20
10
Bi
2
O
3
10
20
30
40
60
70
80
TiO
2
Mol%
2:3
1:4
12:1
6:1
Bi
2
O
3
/TiO
2
mole
Figure 8.23 Part of the phase diagram of the Bi
2
O
3
a
TiO
2
a
KF
a
H
2
O system under
hydrothermal conditions
[87]
.
