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Chapter VIII Micro-hardness studies…
material nature using Wooster’s empirical relation; they also calculated the
values of C11 from micro-hardness, where C11 is first order elastic stiffness
constant. Kannan et al [53] have studied the influence of La +3 ions on growth
of KDP crystals. They confirmed by using Vickers micro-hardness that the
presence of La +3 ions in the superfacial crystal growth layers produced weak
lattice stress. Recently, Ramakrishna Murthy and Venkateshwar Rao [54]
have reported the study of He + ion beam modification of the (100) surfaces of
KDP and ADP crystals relative to the as grown to assess, the nature and
extent of radiation damage. The measurements of micro-hardness studies on
planar plastic anisotropy in as grown surfaces relative to ion bombarded
surfaces have been made by the employing the Knoop indenter. The results
have been interpreted in terms of the nature of bonding, bond strength and
radiation damage on the ion bombardment. Also, they have observed plastic
anisotropy in these surfaces which is found to be in conformity with (100)
plane on which indentations are made. The micro- indentation technique has
recently been employed to characterize the KDP crystals grown by
Sankaranarayan Ramasamy (S-R) method. Balamurugan et al [55] have
studied the micro-hardness of S-R method grown (001) directed KDP crystals.
Moreover, Balamurugan et al [56] have studied the effect of KCl and
measured the micro-hardness of KDP crystals.
Altogether, attempts have been made to study the micro-hardness of
KDP-ADP mixed crystals. Srinivasan et al [57] have studied Vickers micro-
hardness of different 19 compositions of KDP-ADP mixed crystals. Apart from
this, Sengupta and Sengupta [58] have reported results of micro-hardness
studies of ADP-KDP single crystals. Rajesh et al [43] have reported that the
organic additives improved the mechanical strength of KDP crystals. Pritula et
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