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Chapter II Solution Growth….
and amount of solution, and the crystal size. For the supply of uniform
nutrition supply to all growing faces of a crystal, spiral motion of the crystal
has been advocated. There are several other types of crystal motion,
mechanisms are proposed, for example, eccentric unidirectional, eccentric
reversive, planatory rotation, reciprocating, circular motion, magnetic agitator,
etc. More recently, accelerated seed rotations based on microprocessor
controlled or programmable seed crystal movements have been proposed. A
set up designed and fabricated having bi-directional accelerated seed rotation
controller for solution growth has been employed for the growth of KDP
crystals [47], which is useful for forced convection configurations to maintain a
higher homogeneity of the solution. Using 5 liter capacity crystallizer with
accelerated crucible rotation technique (ACRT) and simulated platform
geometry to control the hydrodynamic conditions, Dixit et al [48] reported
rapid growth of KDP crystals along (100) and (001) directions.
2.10 Crystal Habit
The shape or habit, which a crystal achieves in the process of its
growth, is highly sensitive to growth conditions and reflects the growth
mechanism [37, 49]. Therefore, growth shapes make it possible to judge the
conditions prevailing during growth and growth parameters affecting. The
following conditions and parameters have been discussed [33, 37].
Kinematics
Polyhedral shapes are obtained when each face remains parallel to
itself in growing, i.e., when the growth rate depends exclusively on the surface
orientation and is equal on the average for all points: V = V (n). It has been
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