What is the Difference between Zinc and Aluminum Anodes? Why are they Sacrificial?
A – Both are low on the electro-negativity series chart. in comparison with Steel. Steel is the most common Metal used for Ships, Wharfs, Offshore Structures, etc…, so where there is continuing Electrolysis in Water (especially Salt Water), a Dissimilar Metal or Impressed Current has to be present to Give up (Sacrificial) Electrons to Neutralize the Current Created. Zinc is a little Cheaper Metal than Aluminum and does not last as long as in the same Electrolysis conditions. Aluminum is more expensive, but last longer. It generally works out to be the same cost over the same duration.
