This paper presents the experimental evaluation of a recently developed model for predicting the maximum pit size possible on a stainless steel surface under a certain set of atmospheric conditions. Prediction of the maximum pit size possible on 304L and 316L was accomplished by coupling the maximum cathode current available from a thin film of ferric chloride covering the steel's surface to the minimum current needed by a growing hemispherical pit. The experimental validation involved exposure tests of 304L and 316L steel samples covered by thin film of ferric chloride solution at a relative humidity of 97% with a loading density of 400 μg cm −2 . Evaluation of the maximum pit size model was done by comparing the pit size from the model with the pit size obtained from exposure tests at the same atmospheric conditions. The model was found to bound all of the experimental data for both alloys if it was assumed that the critical pit solution was between 60% and 80% of the saturation concentration.

I would first like to thank my advisor, Dr. Robert Kelly, for all his support and guidance while a graduate student as well as an undergraduate at the University of Virginia. I will be forever grateful for the countless opportunities he has given me. I would also like to acknowledge my other committee members, Dr. James Burns and Mr. William Keene for their assistance with my research. At Virginia Tech, I would like to thank Dr. James Schiffbauer for his assistance with the focused ion beam. In addition, I would like to acknowledge all of the faculty and students in the Center for Electrochemical Science and Engineering who have helped me over the years. In particular, thanks to Jen Warner, Cortney Crane, Katie Fleming,

Literature values prove the existence of maximum pit size. Values from exposures to natural environments exist for a range of materials in which exposure times of 10 y or more clearly show a plateau in the size of the largest pits. A recently published model uses the conditions that result from atmospheric exposures to place a bound on the size to which a pit can grow. Although this approach has been shown to compare well to data collected from exposures of stainless steels over long times (> 25 y) at coastal locations, laboratory validation is required in which salt loading density, RH and temperature can be rigorously controlled. After three months, the laboratory exposures of four stainless steel alloys, with 240 and 600 µg/cm 2 of NaCl and 90 and 95% RH, were found to have little pit damage, and all pit sizes were correctly bounded by predicted model values.