Simple algorithms for 1D oxygen concentration profile in an occluded region

Crevice corrosion, pitting or stress corrosion cracking (SCC) of steel, stainless steels, nickel base alloys, or other metallic materials such as titanium can occur in aerated solution due to a differential oxygen (O2) concentration cell (OCC). An O2 concentration gradient exists in solution between the bulk and the occluded region and within the occluded region itself. Since O2 concentration in the occluded region can vary significantly in a non-linear manner in the direction perpendicular to the metal wall(s), it is a challenge to model the corrosion system in one-dimension (1D) by considering O2 reduction at the metal wall(s). There is a need for a method that can quantitatively describe this O2 concentration in 1D. This work serves to derive simple algorithms to fulfill the above purpose. Discussion of the validity boundaries of the simple algorithms is provided.