Question

Discuss in brief sacrificial anode method of corrosion protection. 

Answer 1

1. To achieve protection by sacrificial anode method, the metal to be protected from corrosion is connected by a wire to another piece of metal which is more reactive than the base metal itself.
2. This results in the corrosion of the piece of metal, connected thereby saving base metal.
3. Since the more active metal sacrifices itself, by undergoing corrosion and saving the base metal the method is named as sacrificial anode or auxiliary anode method.
4. The metal normally used are Mg, Zn or Al.
5. The method is generally used to protect cable or iron pipelines, by connecting them to Mg blocks, and in case of marine structures, ships are protected by suing Zn plates as sacrificial anode. Even water tanks, boilers are protected by using Zn metal.