Geoscience Reference
In-Depth Information
Figure 4.1 Phase diagram for the
H
2
O
a
CO
2
system
[8]
.
P
(bar)
70
75
80
900
90
100
125
125A
150
700
500
200
250
300
400
500
700
1000
300
100
200
400
600
T
(
°
C)
Figure 4.2 NC diagram for the
system Na
2
O
a
ZrO
2
a
SiO
2
[9]
.
Na
4
Zr
2
Si
3
O
12
A
B
(I)
I+II+III
I + II (trace)
CD
0
10
20
30
40
50
C
NaOH
wt%
indicate the regions of monophase crystallization and dashed lines indicate the
beginning of crystallization of the excess component. Similarly, temperature versus
concentration diagrams (TC diagrams) are also popular for some of the systems,
because the variation in temperature of the system can lead to the formation of var-
ious polymorphic modifications and several other phases which are not normally
observed in NC diagrams.
Figure 4.4
shows the TC diagram for the system
K
2
O
H
2
O
[11]
. These nonconventional diagrams are relatively
easy to obtain and are highly useful for the growth of single crystals as they clearly
depict the growth conditions. Similarly, just as in the case of conventional phase
a
La
2
O
3
a
P
2
O
5
a
