Which combination is required for corrosion to occur?

Which combination is required for corrosion to occur?

• A. Bare metal, moisture, and oxygen
• B. Bare metal, oxygen, and nitrogen
• C. Bare metal, moisture, and carbon dioxide
• D. Bare metal, hydrogen, and oxygen

Answer: (A)

Corrosion is an electrochemical process that needs three ingredients: a metal surface, an electrolyte, and an oxidizer. The bare metal provides the site where oxidation can occur. Moisture acts as the electrolyte, allowing ions to move between different areas of the metal. Oxygen is the oxidizer that accepts electrons at the cathode, forming oxide. When all three are present, the metal continuously loses electrons and oxidizes, producing rust or other metal oxides. If moisture isn’t present, the ions can’t flow efficiently, so corrosion slows dramatically. If oxygen isn’t present, the oxidation step is limited, so corrosion still slows. If a gas like hydrogen is present instead of moisture, there isn’t a sustained electrolyte to carry the charge, so corrosion is much less likely. Therefore, bare metal, moisture, and oxygen together create the conditions for corrosion to occur.

Corrosion is an electrochemical process that needs three ingredients: a metal surface, an electrolyte, and an oxidizer. The bare metal provides the site where oxidation can occur. Moisture acts as the electrolyte, allowing ions to move between different areas of the metal. Oxygen is the oxidizer that accepts electrons at the cathode, forming oxide.

When all three are present, the metal continuously loses electrons and oxidizes, producing rust or other metal oxides. If moisture isn’t present, the ions can’t flow efficiently, so corrosion slows dramatically. If oxygen isn’t present, the oxidation step is limited, so corrosion still slows. If a gas like hydrogen is present instead of moisture, there isn’t a sustained electrolyte to carry the charge, so corrosion is much less likely.

Therefore, bare metal, moisture, and oxygen together create the conditions for corrosion to occur.