Corrosion can be controlled by changing the material, the environment, the electrochemical potential or the physical barrier between them.

Material and design choices

Choose alloys that form stable protective films in the intended environment, avoid unfavorable galvanic couples, drain trapped liquids, and eliminate crevices where local chemistry can become aggressive.

Coatings

A barrier coating reduces contact between material and environment. Its effectiveness depends on adhesion, permeability and damage tolerance. A metallic coating can also provide electrochemical protection: zinc on steel remains useful at a scratch because zinc is preferentially oxidized.

Cathodic protection

The protected structure is shifted toward cathodic behavior so that its oxidation rate is reduced. This can be achieved with sacrificial anodes or an externally powered impressed-current system.

Environmental control and inhibitors

Reducing humidity, oxygen, aggressive ions or temperature can slow corrosion. Corrosion inhibitors are additives that reduce anodic dissolution, cathodic reaction rates or both, often by changing surface chemistry.

No strategy is universally best. A coating that works in atmospheric exposure may fail under immersion; cathodic protection that is effective for buried steel may be inappropriate for another alloy. Corrosion control is therefore a system-design problem involving material, geometry, environment, maintenance and expected damage.