Introduction:

The use of Zn (zinc) as sacrificial or cathodic protection to prevent rusting of iron is a well-established method in corrosion prevention. This process involves the utilization of a more reactive metal (Zn) to protect a less reactive metal (iron) from corrosion. The reaction between Zn and iron creates a barrier that inhibits the formation of rust and extends the lifespan of iron structures.

How does it work?

1. Sacrificial Protection:
In sacrificial protection, Zn acts as a sacrificial anode, meaning it sacrifices itself to protect the iron. This process involves a redox reaction, where Zn undergoes oxidation to prevent the oxidation of iron. The following steps explain how this protection mechanism occurs:

- Anode: Zn, being more reactive than iron, serves as the anode in the electrochemical cell formed with iron. It oxidizes and loses electrons more easily than iron.
- Cathode: Iron acts as the cathode, where reduction occurs. It gains electrons released by the oxidation of Zn.
- Electron flow: Electrons flow from the Zn anode to the iron cathode, preventing the corrosion of iron.
- Zn corrosion: As Zn oxidizes, it forms Zn2+ ions and releases electrons. These electrons travel through the metallic path to the iron cathode.
- Rust prevention: The released electrons reduce the probability of oxygen reduction at the iron surface, preventing the formation of rust.

2. Cathodic Protection:
Cathodic protection is another method where Zn is used to protect iron from rusting. In this process, Zn acts as a cathode and forms a protective layer, preventing the oxidation of iron. The following steps explain how this mechanism works:

- Cathode: Zn, being less reactive than iron, acts as the cathode in this process.
- Anode: Iron functions as the anode and undergoes oxidation.
- Electron flow: Electrons flow from Zn cathode to the iron anode, preventing the corrosion of iron.
- Zn layer formation: Zn ions from the anode react with water and hydroxide ions, forming a protective layer of Zn(OH)2 on the iron surface.
- Rust prevention: The Zn(OH)2 layer acts as a barrier, preventing the entry of oxygen and moisture, which are essential for rust formation.

Advantages of Zn sacrificial or cathodic protection:
- Zn sacrificial or cathodic protection is a cost-effective method to prevent rusting of iron, as Zn is readily available and less expensive than iron.
- It is relatively easy to install and maintain.
- This method provides long-lasting protection to iron structures, extending their lifespan.
- Zn sacrificial or cathodic protection can be applied to various iron structures, such as pipelines, bridges, and offshore platforms.
- It is environmentally friendly, as Zn is non-toxic and can be recycled.

Conclusion:
The use of Zn as sacrificial or cathodic protection is an effective way to prevent rusting of iron. By sacrificing