Cathodic Protection Tester Practice Exam

In the galvanic series, how do more active metals behave when connected to less active metals?

1. They remain unaffected

2. They corrode very little

3. They corrode well

4. They conduct electricity better

The correct answer is: They corrode well

In the galvanic series, more active metals exhibit a tendency to corrode when connected to less active metals. This behavior is grounded in electrochemical principles, where the more active metal serves as an anode and undergoes oxidation, losing electrons. These electrons then flow to the less active metal, which acts as a cathode and is protected from corrosion. The driving force behind this corrosion process lies in the relative positions of metals in the galvanic series, which ranks metals based on their electrochemical activity. When a more active metal comes into contact with a less active metal, a potential difference is created, facilitating the flow of electrons and therefore leading to noticeable corrosion of the more active metal. This phenomenon is critical in many applications, especially in cathodic protection systems, as it helps protect important infrastructure from degradation by understanding and preventing galvanic corrosion.