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Chapter VII In this chapter the dislocation etching study of L-histidine, L-
threonine and D L-methionine (amino acid) doped KDP crystals has been
explained. The chemical etching technique is quite simple and provides very
interesting results regarding the delineation of dislocations on the crystalline
plane. Many times the impurity plays important role in dislocation etch-pitting.
The etching is carried out at different temperatures on {110} plane of pure and
amino acid doped KDP crystals by using glacial acetic acid as the etchant. Flat
bottom rhombus type etch pits are obtained. The reactivity at line defects and
kinetics of the motion of ledges of etch pits is studied by applying the Arrhenius
law. Various kinetic and thermodynamic parameters are obtained. The effect of
the doping on the kinetic and thermodynamic parameters is observed in
comparison to the pure KDP crystals. Doping do influences the etching behavior
of amino acid doped KDP in comparison to pure KDP, but the change in
concentration of dopant does not have any systematic effect on etching
parameter values. Impurity is expected to produce shallow flat bottomed etch
pits. Therefore, the doping of different amino acid is expected to alter chemical
etch pitting behaviors. This study is conducted for pure and all three amino acids
doped KDP crystals with doping of amino acids in different concentrations.
Chapter VIII deals with the micro-indentation hardness of pure and L-histidine, L-
threonine and DL-methionine doped KDP crystals. For any device application,
various mechanical properties are very important. The variation of Vickers micro-
hardness with applied load is studied. As the applied load increases the Vickers