XPS imaging investigations of pitting corrosion mechanisms in Inconel 600

The surface chemistry associated with pitting corrosion on a nickel‐based alloy, Inconel 600, has been studied using imaging x‐ray photoelectron spectroscopy. The irregularity of the sample surfaces necessitated a more elaborate background correction than is usually applied in such imaging. Areas of active pitting were found to contain corrosion products that are high in chromium oxide and depleted in nickel and iron. Sites of anodic activity on the surface were able to be defined more clearly using principal component analysis. Elements that are dissolved preferentially are deposited cathodically within well‐defined regions whose distance from the anodic pit appears related to the open‐circuit potential.