Prevention of Corrosion Notes

Corrosion is a gradual degradation of metal when it comes in contact with surroundings like moisture and air, thus forming the oxides of the metal on its surface. Metals undergo corrosion easily, and due to this, their strength is also affected. 

The corrosion of iron is commonly known as rusting. It can be prevented by certain methods, including applying oil on the metal surface. The corrosion of metals can occur at any time it comes in contact with its surroundings, leading to deterioration. This phenomenon is called corrosion, and the metal on which this phenomenon occurs is known as corroded metal.

Measures of Prevention Of Corrosion

Since corrosion weakens the metal and reduces its strength. It is important to prevent the metal from corroding easily. The process of corrosion can be prevented by the following measures.

Coating

The process of corrosion can be prevented by applying a layer or a coat of non-corrosive metal on the surface of metals which must be protected. The metals can be coated with epoxy and acrylic to reduce their corrosion.

Cathodic Protection

Corrosion takes place when the metal is in contact with water for a long period of time. Pipelines which are situated inside the sea and saltwater are more prone to corrosion as oxides are easily deposited in salty water. With this method, DC current is applied to metals. The impressed current method, also known as cathodic protection, is used for the protection of large ships which are constantly underwater.

Sacrificial Method

The sacrificial method is yet another method to prevent metal from being corroded. A metal of higher reactivity is placed beside the metal to be protected. Thus, the higher reactivity metal sacrifices itself to prevent the main metal from corroding. This method is used with pipelines which are fitted underground.

Galvanisation

With the help of galvanisation, the corrosion of metals can be prevented. It is the most efficient method in terms of corrosion prevention. The electroplating of zinc metal takes place in the process of galvanisation over the metal which is used to prevent corrosion. This technique is usually used in preventing bicycles and motorcycles from being corroded.

Oiling The Surface

The corrosion of metal can be prevented when their surfaces are oiled or greased. When the surface is oiled, then a protective film is formed between the metal and its surroundings, preventing direct contact between them. Thus, this prevents corrosion for long periods of time. The oiling of metal surfaces is the most common and cost efficient method of preventing corrosion.

Alloying

Metals can avoid corrosion when they are not used in their pure forms. The metal gets mixed with another metal and the alloy is used. The alloy which is so formed does not get corroded easily. The alloy of iron and chromium is stainless steel which does not corrode easily when it comes in contact with its surroundings even for long periods of time.

Painting

Paint can help in the prevention of corrosion. Paint must be applied regularly to do this. When the paint surface gets scratched from any sides, then it must be repainted again. The process is also cost efficient and commonly used in homes. The quality of paint must be good to ensure that it helps the metal maintain its appearance. The metal oxide commonly known as primer is used to coat the iron surface to prevent rusting. Multiple layers of paint can prevent the surface from corrosion.

Hot Dip Galvanisation

Corrosion can also be prevented when metals are dipped in the hot molten metal of zinc or chromium to electroplate their surface. This ensures that the metals are coated and helps avoid contact with its surroundings. The plated layer can be applied multiple times depending on the nature of metals which is used to prevent it. The dipping of metal increases the equality and cost of the metal as well.

Conclusion

Corrosion is defined as the transformation of metal into another form when it is exposed to sunlight and water for long durations. The corrosion of iron is commonly known as rusting and can be prevented by applying oil on its surface. There are a number of ways to prevent the corrosion of metals. Jewellery also corrodes easily and changes colour. To prevent corrosion, you can take preventative measures, such as oiling the surface, galvanising the metal surface, hot dipping of metal, sacrificial method etc. Prevention is necessary as corrosion weakens the metal strength and gradually eats it up.