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Chapter VII Reactivity at Dislocation….
current, voltage, time, nature and pressure of the gas and the arrangement of
anode and cathode, the individual crystals of the sputtered surface may become
smooth, showing only the grain boundaries, or they may be etched, showing
structure within the crystals.
7.3 Etching process
When the rate of dissolution of a solid is rapid, the process is controlled by
the rates of chemical and thermal diffusion in the solvent. As the dissolution rate
or the under saturation of solvent becomes smaller, the surface imperfections of
the solid play prominent role [12].
Figure:7.1 Surface imperfection on a crystal.
The unit process in dissolution can be considered as a removal of a molecule
from the corner of a kink in a surface step; however, the process occurs only if:
(a) a step exists on the surface, (b) the step contains kinks and (c) the solvent is
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