Magnesium Anodes

The vital role of a galvanic anode 

A galvanic anode serves a vital role in any submerged metal structure. It provides the metal structure from corrosion thereby protecting its integrity and extending its life. Under submerged conditions the metal structure corrodes rapidly hence a system to protect this structure from corrosion is required. This is where the galvanic anode carries out its vital role. The right type of galvanic anode will result in cost savings and offer a higher level of protection against corrosion for the metal structure. This is why it is essential that the right material of galvanic anode is selected. 

What materials are galvanic anodes available in?

Galvanic anodes come in three major materials-- magnesium, aluminium and zinc. Each material has its own advantages and disadvantages. Out of these three materials magnesium has the most negative electropotential. This makes it highly suitable for areas where the soil or water (where the metal structure is submerged) resistivity is higher. Such areas include on-shore pipelines, as well as other buried metal structures. 

Alongside the anode's material, a number of factors influence the life of a galvanic anode, including:

• Quality of the water
• The salinity of the water- the higher the salinity the faster the corrosive processes and the faster the anode will deteriorate 
• The number of anodes placed on the metal structure- the higher the number of anodes the longer each of them will serve its purpose

The wide usage of magnesium anodes in Australia

Magnesium anodes are commonly referred to as soft water anodes. These can be found in the majority of tanks across Australia and also in fresh water rivers.

There are a wide variety of types available such as-- solar rods, straight rods, flexi rods as well as multi flexi rod anodes. 

How do magnesium anodes protect metal structures?

Magnesium Anodes protect submerged metal structures by a specific electrochemical action. This is referred to as sacrificial protection where the magnesium anode corrodes (sacrifices itself) instead of the metal structure. This type of electrolytic corrosion control is known as 'Cathodic Protection'. The anode rod is a very important component in the tank's life with regular inspection and with regular replacement of this anode the tank life can be greatly extended.

The advantage of these anode systems is that no external power source is required, plus they are relatively easy to install. Also anode systems are easy to monitor over time by trained personnel.