Question

Define area effect regarding galvanic corrosion?

(a) cathodic area * anodic area

(b) anodic area/cathodic area

(c) cathodic area/anodic area

(d) cathodic area + anodic area

This question was posed to me in a national level competition.

My question is based upon Eight Forms in portion Eight Forms of Corrosion of Corrosion Engineering

Answer 1

Correct option is (c) cathodic area/anodic area

To explain I would say: It is the ratio of cathodic to anodic areas. An unfavorable area ratio with a large cathodic area and small anodic area results in high current density at the anode. The greater the current density at an anodic area the greater the corrosion rate.