Distinguish between anodic protection and cathodic protection.
|Cathodic protection||Anodic protection|
|The basic principle is to force metal to be protected to behave like cathode||The basic principle is to increase passivity of base metal by applying currentin the direction in which metal would become more anodic|
|The cathodic protection involves reverse the flow of current between two dissimilar electrode||The anodic protection involves suppression of anodic reaction by adjusting potential of the more reactive metal|
|The cathodic protection can be achieved by sacrificial method and impressed current method||There are no different methods for anodic protection|
|It protect long length structure for long duration||It can protect complicated structures|
|It is not very costly||The initial cost is high ,though operating cost is low|
|It can provide steady, consistent protection for long term||It may not provide steady protection. If it go out of control , the rate of corrosion increase suddenly|