Depolarization currents have been investigated for thermally and mecha
nically pretreated NaCl crystals doped with divalent nickel ions. The
models of Debye and Maxwell-Wagner-Sillars polarizations have been exp
loited to describe the behavior of ITC bands detected below (dipolar),
near and above (interfacial) room temperature, respectively. The NaCl
:Ni2+ system was especially interesting for kinetic studies because th
e dopant ions are distinctly smaller than the matrix cations. It has b
een found that the precipitation phenomena can be understood in terms
of an Avrami-approach of the process mainly occurring in the stress fi
elds of dislocations. The migration of impurities is controlled by the
diffusion of cation vacancies.