The influence of static stress on the corrosion behavior of 316L stainless steel in Ringer's solution.

The decrease in corrosion resistance of 316L stainless steel due to static stress was studied in vitro using a 37 degree C Ringer's solution electrolyte. Both potentiodynamic polarization and coulometric techniques were used. Cyclic anodic polarization tests with highly loaded fracture mechanics samples revealed a lowering of breakdown potential and disruption of passive films compared to unstressed controls. Measurements of the time-averaged current density due to a 100 mV anodic overpotential showed that a stress level causing plastic deformation increases the current density by more than an order of magnitude compared to samples stressed to the yield stress or nonloaded controls. The significance of these findings for surgical implant devices in service is discussed.