Fretting corrosion is caused by which scenario?

• A. Small relative motion between contacting surfaces
• B. High pressure load without movement
• C. Oxidation in dry air
• D. Chemical dissolution without wear

Answer: (D)

Fretting corrosion happens when surfaces in contact experience tiny, repeated sliding against each other. That minute motion causes wear of the protective oxide film at the contact patch, exposing fresh metal that can rapidly corrode in the environment. The cyclic slip and the resulting disruption of the protective layer together drive the accelerated corrosion at the contact point. A high static load without movement won’t produce this repeated sliding; oxidation in dry air is general corrosion without wear; chemical dissolution without wear is pure chemical attack without surface sliding.