To control crevice corrosion, two common approaches are

• A. Cleaning and painting
• B. Coatings
• C. Grinding and smoothing
• D. Design and cathodic protection

Answer: (D)

Crevice corrosion happens when a small, confined space in a metal joint or deposit traps electrolyte, creating a local chemistry that accelerates metal loss. The most effective way to control it is to remove or minimize those crevices in the design and to counter the corrosion process with cathodic protection. Designing connections to be seamless or with proper seals, avoiding gaps under bolts or gaskets, and using compatible materials reduce the pockets where stagnant solution can form. Cathodic protection then shifts the metal’s potential so it is less likely to dissolve in the confined areas, even if some crevice remains.

Coatings can help some general corrosion but often fail inside crevices where the coating is stressed or breached; grinding or smoothing the surface doesn’t remove the crevice geometry; cleaning removes deposits but doesn’t stop crevice formation. Therefore, reducing or eliminating crevices and applying cathodic protection address the fundamental conditions that drive crevice corrosion.