A process called galvanic corrosion is a common form of rusting that occurs in salt water. Do not confuse this with electrolysis. They are not the same process. It occurs when two or more different metals make electrical contact with one another in seawater. In this electrochemical process, they have essentially become a battery and some current will flow between the metals. One of the metals in the pair acts as an anode. This causes it to corrode more quickly than it would if left by itself. Alternatively, the other metal becomes the cathode and corrodes more slowly than it would alone. How each metal in the couple behaves on its own in seawater is not the issue. The problem is that when there is contact with a different metal, the rates of corrosion will change. Corrosion of the anode will speed up and decay of the cathode will slow down or stop entirely. Fortunately, the use of a sacrificial zinc anode helps to alleviate this ever present|pervasive) problem.