Most metals exposed to a liquid phase corrosive environment can be protected from aggressive corrosion attack using an electrochemical prevention technique, either cathodic protection (CP), anodic protection (AP) or potential adjustment protection (PAP). Which of these methods of protection is appropriate depends primarily on the metal/environment characteristics.
Whether or not a metal can corrode in a particular environment can be determined thermodynamically. For instance, Figure 1 is a diagram for steel in an aqueous environment which shows domains of immunity, corrosion and passivity with relation to the steel electrical solution potential and solution pH.
