Geoscience Reference
In-Depth Information
Figure 5.39 Solubility of KTP
(in wt%) in 1 M
K
2
HPO
4
1
0.5KPO
3
at 10 kpsi
[148]
.
1 mm K
2
HPO
4
(+0.5 m KPO
3
)
10 kpsi
6 days
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
400
450
500
T
(
°
C)
550
600
650
The solubility of KTP in 1 M K
2
HPO
4
1
0.5KPO
3
solutions has been studied in
detail
[148]
.
Figure 5.39
shows
the solubility of KTP (in wt%)
in 1 M
K
2
HPO
4
1
0.5KPO
3
at 10 kpsi. The solubility data indicate good solubility for
growth at 600
C and a positive TC.
KTP crystals, using a complex mixture of water-soluble phosphate glasses,
KTP, solvents, and water, have been obtained by several researchers. The glass
composition is K
2
O (42
70), TiO
2
(1
18), P
2
O
5
(26
55) (mol%). The opti-
2
2
2
mum ratio K/P is equal to 0.8
2.5, optimum glass composition is K
2
O (55
60),
2
2
P
2
O
5
(38
5) (mol%).
Byrappa (1996)
[152]
has carried out an extensive study on the solubility and
growth of KTP under lower temperature and pressure conditions. The main objec-
tive of this study was to find a suitable mineralizer solution in order to increase the
growth rate, solubility, and crystal quality, but at reduced PT conditions. As is well
known from the literature survey, the hydrothermal technique is most suitable for
the growth of KTP crystals as it produces high-quality defect-free crystals.
However, the main problem with the use of the hydrothermal technique for the
growth of KTP crystals is the higher PT conditions of growth. In fact, when the
early hydrothermal experiments were carried out, the PT conditions were rather
high (P
5
1.5
2 kbar; T
5
650
700
C). The higher PT conditions do not yield
large size crystals and the cost of the experiments involved is rather high.
Subsequently, the inflow of the research data particularly on the PVT relations in
several related systems of K
2
O
42), TiO
2
(1
2
2
TiO
2
P
2
O
5
has brought down the PT conditions
425
C. Recently, the material aspects,
structural, physical, and chemical properties, and device feasibility of the KTP fam-
ily of crystals have been reviewed
[153]
.
Investigators have carried out hydrothermal experiments within a wide range of
PT conditions using Morey- and Tuttle-type autoclaves. The nutrient materials
were taken in Teflon liners for experiments at lower PT conditions (using the
Morey type of autoclaves) and in platinum liners for experiments at higher PT
to the tune of P
10 kpsi and T
375
5
5
2
