1. pH

2. ratio of anode to cathode areas

3. position of metal in galvanic series

Factors affecting Rate of corrosion

1. pH

Generally acidic media have more corrosive effect on metal Amphotenc metals are more attacked by alkaline media Al, Zn, Pb,

Thus every metal gets corroded minum at certain pH medium and at the pH of medium higher or lower than that, the corrosion of the metal is faster.

2. Ratio of anode to cathode areas

A better metallic design by use of two metals is the one in which anodic area is much larger than cathodic area

3. Position of metal in galvanic series

More the metals are apart in galvanic series faster is the corrosion Dry corrosion is also faster in more active metals