Another form of electrochemical corrosion is crevice corrosion. Crevice corrosion is a consequence of concentration differences of ions or dissolved gases in an electrolytic solution. A solution became trapped between a pipe and the flange on the left. The stagnant liquid in the crevice eventually had a lowered dissolved oxygen concentration and crevice corrosion took over and destroyed the flange. In the absence of oxygen, the metal and/or it’s passive layer begin to oxidize. To prevent crevice corrosion, one should use welds rather than rivets or bolted joints whenever possible. Also consider nonabsorbing gaskets. Remove accumulated deposits frequently and design containment vessels to avoid stagnant areas as much as possible.

Figure 3: Crevice Corrosion