Corrosion Process Overview

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What is the driving force necessary for electrons to flow between anodic and cathodic areas in corrosion?

Difference in potential

Why does corrosion always occur at the anodic area of the metal?

Due to the oxidation process

What is the main cathodic reaction involving hydrogen in a deaerated and acidic medium?

2H+ (aq) + 2e− → H2

In a deaerated and neutral medium, what reaction leads to the liberation of H2 and formation of OH− ions?

2H2O + 2e− → H2 (g) + 2OH− (aq) Signup and view all the answers

Which cathodic reaction involves the reduction of oxygen in an aerated and neutral medium?

O2 (aq) + 2H2O + 4e− → 4OH−(aq) Signup and view all the answers

What is the most common cathode reaction in corrosion due to the presence of dissolved oxygen?

Oxygen reduction Signup and view all the answers

What is galvanic corrosion?

Galvanic corrosion occurs when two dissimilar metals are in physical contact in an aqueous electrolyte. Signup and view all the answers

Which metal acts as the anode in galvanic corrosion?

The less resistant metal acts as the anode. Signup and view all the answers

What function does the more resistant metal serve in galvanic corrosion?

The more resistant metal functions as the cathode. Signup and view all the answers

Explain the concept of microgalvanic cells.

Microgalvanic cells are formed when small differences in electrode potentials exist within a material. Signup and view all the answers

What process occurs at the anodic areas in galvanic corrosion?

Oxidation process occurs at the anodic areas. Signup and view all the answers

In which direction does electron flow happen in galvanic corrosion?

Electron flow goes from the anode to the cathode. Signup and view all the answers

What happens at anodic sites in the corrosion process?

[Fe -> Fe 2+ + 2e-] Signup and view all the answers

What is the overall reaction in the corrosion process involving iron and oxygen?

2Fe + O2 (g) + 2H2O (l) -> 2Fe2+ (aq) + 2OH- (aq) Signup and view all the answers

What is the difference between dry corrosion and wet corrosion?

Dry corrosion involves direct attack of atmospheric gases, while wet corrosion occurs due to the existence of separate anodic and cathodic areas. Signup and view all the answers

What is the purpose of the galvanic series?

The galvanic series ranks metals and alloys based on their corrosion tendencies/resistance in natural seawater. Signup and view all the answers

Describe the formation of yellow rust in the presence of oxygen.

4 Fe (OH)2 + 2 H2O + O2 -> 2 [ Fe2O3. 3H2O] Signup and view all the answers

What happens if the supply of oxygen is limited in the corrosion process?

6 Fe (OH)2 + O2 -> 2 [ Fe3O4. 3H2O] Signup and view all the answers

Corrosion Process Overview

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