What combination of elements is needed for corrosion to occur on metal surfaces?

What combination of elements is needed for corrosion to occur on metal surfaces?

• A. Oxygen, moisture, and bare metal
• B. Oxygen only
• C. Moisture only
• D. Bare metal only

Answer: (A)

Corrosion is driven by an electrochemical reaction that needs three things: an oxidizer, a source of electrolyte, and a metal surface that can be oxidized. Oxygen supplies the oxidizing agent, moisture provides the electrolyte that allows ions to move, and a bare metal surface offers the material to be oxidized. When all three are present, rust or other corrosion forms readily develop on the exposed metal. If any one element is missing—no oxygen, no moisture, or a coating that separates the metal from the environment—the reaction can’t proceed as quickly or may be halted.

Corrosion is driven by an electrochemical reaction that needs three things: an oxidizer, a source of electrolyte, and a metal surface that can be oxidized. Oxygen supplies the oxidizing agent, moisture provides the electrolyte that allows ions to move, and a bare metal surface offers the material to be oxidized. When all three are present, rust or other corrosion forms readily develop on the exposed metal. If any one element is missing—no oxygen, no moisture, or a coating that separates the metal from the environment—the reaction can’t proceed as quickly or may be halted.