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Figure 5.30 Yield of GaPO 4 single crystals as a
function of time [129] .
0. m (g)
0.3
0.2
0.1
2
46 8
τ
(days)
Solubility (mol l 1
2.5
160 ° C
2
180 ° C
1.5
200 ° C
1
250 ° C
0.5
% H 2 SO 4
0 0
20
40
60
80
100
Figure 5.31 Solubility of GaPO 4 in the phospho-sulfuric acid solution 15 M H 3 PO 4 1 9M
H 2 SO 4 [122] .
Source: Courtesy of the Gauthier-Villars/ESME, Paris.
Table 5.11 Crystallization Kinetics for GaPO 4
Solvent HCl
HNO 3
KF
NaOH
T ( C)
200
250
300
200
250
300
200
250
300
200
250
300
K
0.22
0.48
0.76
0.11
0.28
0.41
0.09
0.14
0.26
0.04
0.05
0.15
N
0.61
0.58
0.57
0.58
0.50
0.47
0.20
0.22
0.18
0.30
0.28
0.27
5.4.2 Morphology
The morphology of the GaPO 4 sin gl e cryst a ls is s ho wn in F igure 5.32 [117] .The
commonly appearing faces are
Figure 5.33 shows
the characteristic photographs of GaPO 4 crystals obtained by hydrothermal
method. The growth rates along various crystallographic directions decrease in the
following sequence:
½
1011
; ½
0111
; ½
1010
; ½
1012
:
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