Question

Which of the following factors affect the corrosion rate of metal?

(a) Relative surface area of an anode and cathode

(b) Nature of the oxide layer

(c) Purity of metal

(d) Relative surface area of an anode and cathode, nature of oxide layer and purity of metal

The question was posed to me during an interview.

The query is from Corrosion and its Classification in chapter Corrosion Principles of Corrosion Engineering

Answer 1

Correct answer is (d) Relative surface area of an anode and cathode, nature of oxide layer and purity of metal

To explain I would say: As the cathodic to anodic area increases, the more oxygen reduction, or more corrosion can occur. The corrosion resistance of aluminum can be attributed to the formation of the thick, dense oxide layer. Impure metals undergo corrosion at a faster rate than the pure metals.