There are a number of methods by which steel is protected from corrosion. One of the most effective methods of effectively protecting steel from corrosion is galvanic protection. This protection simply works by covering the surface of the steel with a metal which will preferentially corrode and protect the steel at the time when it comes with contact with any electrolyte such as water.
All of the metals and their alloys have a characteristic called the electrochemical potential. Now, when the metals that have a high electrochemical potential comes in contact with a metal having low electrochemical potential tend to corrode. This is the reason as to why galvanic coatings are applied to steel since these galvanic coatings have a higher electrochemical potential as compared to steel and as a result the base metal is saved from corrosion whereas the coating is corroded.
Methods of Galvanic Protection
- There are a number of ways by which galvanic protection is offered to steel for preventing it from corrosion. The most common methods used in this regard are as follows.
Hot Dip Galvanisation –
- Galvanising refers to the method of application of a continuous layer of zinc to the surface of steel. In the method of hot dip galvanisation, the steel is dipped into a bath of molten zinc which allows zinc to adhere to the surface of steel.
- This process involves a lot preparation of the surface of the steel and a number of other steps for the process to be effectively completed.
Zinc Rich Primers –
- Zinc rich primer is basically a liquid applied coating on the steel that has a microscopic spheres of solid zinc metal that are held together with a resin.
- There are a number of options for the types of resins to be used. The most commonly used resin for the zinc rich primer is epoxy resin. The coating so formed over the steel help in the prevention of corrosion.
- Now, it can be clearly understood that both of these methods offer galvanic protection of the base metal steel from being affected by corrosion so as to keep them functional for a longer duration of time.
A Comparison Between the Two Methods
A comparison between the two methods that is hot dip galvanisation and zinc rich primers would prove which of the process is a better one.
- The service life of hot dip galvanisation is more as compared to the inorganic zinc rich primer which means when subjected to the same conditions, hot dip galvanisation offers a longer protection as compared to the inorganic zinc rich primer.
- Thus, it is clear that hot dip galvanisation offers more galvanic protection as compared to the zinc rich primers in the same environment.
- Both hot dip galvanising as well as zinc rich primers can be used with a top coating but many times there is a top coating used for additional protection for the preservation of the galvanic layer and for aesthetics along with the protection of the zinc layer at the time when the service conditions are acidic or alkaline in nature.
- Now, zinc being amphoteric in nature does well in the pH neutral environments but quickly deteriorates in case of extremely low or high pH levels.
- This is exactly where surface preparation comes into play. Here, hot dip galvanisation has a better prepared surface without any gaps.
- But in case of top coating of the zinc rich primers, it needs to be carefully done to release the air in the gaps for properly
- sealing the surface which is not needed in hot dip galvanisation. Thus, hot dip galvanisation is a better option as compared to the zinc rich primer.
Since, hot dip galvanisation offers a better solution, it is readily used in the crash barriers, cable trays, earthing material and a number of others. But at any point of time, you are looking for hot dip galvanizing services in Gujarat, make sure you choose a trusted and a reputed one for the best solutions. Tanya Galvanisers would undoubtedly be a very good choice in this regard. With its several years of experience in the field of hot dip galvanisation, you can be assured of getting best of the services.