Pitting corrosion evaluation: a review

Abstract

Pitting corrosion is an insidious localized form of corrosion causing much devastating destruction to structural members such as stainless steel in chloride environment. This paper gives a review of the mechanism processes of pitting, stages, factors facilitating pitting corrosion, techniques of evaluating pitting corrosion and some research work on pitting corrosion. The rudimentary knowledge of the mechanisms of pitting corrosion from this work will be of assistance to the selection process, specification and the use of stainless steels and other structural members.

Global sensitivity analysis of influence parameters in pitting corrosion behavior of 304 stainless steel using adaptive neuro‐fuzzy inference systems

“…Then, the Cl − adsorbed combines with the cations in the passive film to form soluble chlorides, resulting in the formation of pits on the substrate. [ 34 ]…”

Corrosion and Hardness Behaviour of Al/GO Nanocomposites Processed by the Ultrasonic Gravitational Stir Casting Method

“…The corrosion pits observed in the composite sample were shown in Figure 11. The corrosion pits appear cup-shaped, hemispherical, flat-walled, or sometimes irregular-shaped depending upon the preferential corrosion area, adsorption and diffusion of the chloride ions, and immersion periods [31]. The irregular shapes of the corrosion pits were found at the interfacial region between the Al matrix and the GO particles.…”

Pitting corrosion of galvanized pipes in hot water supply systems

“…The accumulation of iron ions in the place of the anode (the lower part of the pitting in Figure 3) causes the diffusion of chlorides and sulfates anions from the bulk of the water. Inside the pitting, iron salts, FeCl2, FeSO4 are formed, which undergo hydrolysis according to reactions (3-4) [12]:…”

“…The "incubation period" of pits can be months or years. The incubation period is the total time required for the structure to pass from the initiation of pitting to the moment when pitting reaches a critical degree, which ultimately leads to catastrophic destruction of the pipe metal [12].…”