Limiting Electrode Potential in Cavities and Its Role in Deciding between SCC (Stress Corrosion Cracking) and HC (Hydrogen Cracking) in Metals

摘要

This paper reviews the conditions needed to determine whether aqueous-phase crack propagation occurs due to hydrogen (HC) or due to anodic metal dissolution (SCC). It shows that the main question to be answered is whether overlap of the electrode potential regions of the metal dissolution and hydrogen evolution reactions increases or decreases with increasing distance x into a cavity or crack. It also reviews the theoretical and experimental basis of the recently discovered existence of a limiting electrode potential in a cavity, a finding which is paramount to the goal of this paper.