EFFECT OF PLASTIC-DEFORMATION ON IONIC-CONDUCTION IN PURE AGI AND AGI-AL2O3 COMPOSITE SOLID ELECTROLYTES

The ionic conductivities of pure silver iodide and silver iodide-( 10- 40 mol%) alumina composites used as solid electrolytes are determined at room temperature by a.c. impedance spectroscopy as a function of co mpression pressure and annealing temperature. The ionic conductivities of both the pure and the composite silver iodide specimens increase w ith increasing compression pressure. This suggests that structural def ects acting as conduction paths are generated in abundance by the plas tic deformation. The mechanical strength of the as-deformed pure silve r iodide specimen is decreased drastically by annealing at 413 K, wher eas that of the as-deformed composite specimens remains virtually unch anged. This indicates that the deformation-induced defects are present largely as dislocations. The ionic conductivity of the as-deformed pu re silver iodide specimen determined during annealing at 323 K decreas es with annealing time, whereas the conductivities of the as-deformed composite specimens are practically unchanged. It is concluded that th e removal of the deformation-induced dislocations during annealing is impeded by dispersed alumina particles.