Characteristics of Pit Initiation of Stainless Steel in Triiodide Aqueous Solution

Abstract

Characteristics of pit initiation of SUS 304L and SUS 316L stainless steels were studied using iodine solutions in which triiodide ions (I₃^-) accumulate with time due to the dissolution of metal between 333 and 363K. The pit initiation process of SUS 304L and SUS 316L stainless steels followed exponential laws. It was found that a stable pit growth in the triiodide solution occurred when the pit depth reached 0.1mm regardless of temperature, the initial triiodide concentration and materials. Stable pit growth had a tendency increasing linearly for SUS 304L and exponentially for SUS 316L with time.