In industrial and manufacturing operations, zinc (Zn) is used for galvanizing other metals. Galvanizing is a process in which metals such as iron or steel are coated.
Conventional steel, either in rain or ambient moisture, is made of iron that can rust when exposed to water. Rust can corrode a steel portion to the point of failure over time. In galvanizing, a zinc coating is applied by a procedure called “continuous hot-dip” to steel parts, in which that part moves through a molten zinc bath. Liquid zinc binds to the iron in the steel and all around the piece to form a protective layer.
Why is zinc added to steel?
Zinc achieves ‘rust prevention’ by oxidizing itself, aside from the obvious advantage of inhibiting corrosion and shielding the carbon steel underneath. Think of it as the zinc that makes the steel solid, almost an act of sacrificing itself. The process also significantly increases the steel’s life span. It’s a very short process that takes just minutes to do, and it’s a perfect match to pair with the steel required to create a large range of products because zinc is common and inexpensive.
A coating of a zinc layer provides protection to minimize rusting and increase the lifetime of steel or aluminum. According to Figueira et al.:
The high corrosion resistance of galvanized steel is attributed both to the galvanic action of zinc and to the barrier effect of zinc products. Zinc has a low-self corrosion rate and, due to its low position in the galvanic series, is an efficient sacrificial anode for galvanic protection of the steel structure.
Advantages of Zinc as a Coating
- Zinc is a crucial component of steel, and one of its most outstanding qualities is its ability to repel rust.
- Notable enhancement in steel’s longevity and reliability has been scientifically proven when it is coated in zinc.
- Nothing else is as effective and economical as a defense of steel against rust.
- Whenever steel is left exposed, it can inevitably corrode in almost all environments.
- Zinc coatings help protect steel from corrosion by a physical barrier and have an electrochemical barrier.
- Zinc-based coatings offer protection to make alloys impervious to moisture and oxygen.
- Galvanic shielding, provided by zinc, can help protect steel by rusting itself first instead of steel or aluminum. (Read: Aluminum vs Steel: Which Metal is Better?)
Figueira, Rita & Silva, Carlos & Pereira, Elsa & Salta, M. (2014). CORROSION OF HOT-DIP GALVANIZED STEEL REINFORCEMENT. Artigo submetido em Junho de 2014 e aceite em Setembro de 2014. Corrosão e Protecção de Materiais. 33. 51.