Influence of an electric field on grain growth in extruded NaCl

(1) An electric field of 0.72 kV/cm retarded both static and dynamic grain growth in extruded polycrystalline 99.9% NaCl, the effect being greater for dynamic growth. (2) Both static and dynamic grain growth were linear with time, giving D - Do* = At and A = Ao* exp (-Q/RT). The field reduced Ao but had no discernible effect on Q. (3) The value of Q was 80 ± 5 kJ/mole in all cases, which is in accord with cation diffusion in NaCl. (4) The reduction in Ao by the field suggests that it reduced the average driving force for grain growth. (5) Abnormal grain growth occurred during dynamic grain growth without an electric field, but not with a field. (6) The present results are concluded to reflect extrinsic behavior.