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Chapter VII Reactivity at Dislocation….
From the figures (7.3 a- h) of pure and 0.3 wt % aof these selected amino acids
doped KDP crystals, one can see that the etch pits are rhombic in nature. Some
of the etch pits are flat bottom and with blunt edges, which are likely to be due to
doped impurities and thus may decorate the presence of doped compounds.
7.7 Kinetic Parameters
During the etching study of alkali halide crystals by various solutions, it has
been found that nature of solvent, nature and concentration of impurities,
temperature, stirring, under saturation, crystallographic orientation of the surface
being etched, segregation of impurities at dislocations and kind of dislocations
affect the formation of etch pits [58]. Moreover, Sangwal [15] has reported the
roles of crystal structure, solvent surface orientation, additive impurities and
reaction products in etching.
Altogether, there are different situations where solution of KDP is used as an
etchant. The defect characterization of solution-grown single crystal of
magnesium sulphate heptahydrate using chemical etching technique was
reported by Karan and Sen Gupta [61], where double distilled water, FeCl3, HCl,
under saturated solution of KDP and saturated solution of KDP were used as an
etchants.
Various authors have reported dislocation and etch pits by using different
etchants on various crystals. It is very laborious to compile all details of etching,
however, Joshi [62] has attempted to compile the details up to a certain extent. In
the present author’s laboratory dislocation etching has been studied extensively
on various crystals, for examples, Bismuth single crystals [63-66], antimony
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