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Chapter VII Reactivity at Dislocation….
studied two counterparts of LiF cleavages and observed mirror images of etch
pits. When metal specimens are used, successive attacks, alternated with electro
polishing, should reveal consistently of the same pattern.
Tests were conducted to check the dislocation sites of etch pits by verification
of the relation; na ≈ nb + nc, where na, nb and nc are the density of etch pits along
the intersecting grain boundaries. Also, the densities of etch pits remained
unchanged with the time suggesting the occurrence of pits at dislocation sites
[40].
7.5 Etching Studies of KDP Crystals
There are numerous researchers who have carried out chemical etching
studies on KDP crystals with different aims. In this section an attempt is made to
summarize the information available in the literature. Usually, the water-soluble
crystals find water as a good etchant. Water easily produce etch pits on these
crystals. The etching capability decreases along the series of homologous
alcohols and acids with addition of a –CH2 group. The change in the solvent not
only changes the etching capability but also the pit morphology and the different
surfaces behave differently to the same series of solvents. This has been
discussed elaborately by Sangwal [39].
Balamurugan et al [48] have reported etching study of KDP crystals on (100)
faces with water as an etchant at room temperature. They observed elongated
rectangular etch pits with dislocation density of the order of 10 2 /cm 2 , further
Balamurugan and Ramasamy [49] have carried out chemical etching on the
(110) faces of KDP crystals grown by Sankaranarayanan–Ramasamy (S-R)
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