what is metal corrosion ? what are the ways to protect corrosion?
Answers
Explanation:
What is corrosion?
Some of the metals that we use in our day to day lives are malleable, strong and ductile. So, when we use these metals, they get exposed to the environment. With the passage of time, they lose their shine and get covered with a coloured layer on them. Some of these metals even lose their strength and become brittle or weak.
This happens because of the chemical interaction between the metals and their environment. So, the spontaneous destruction of metals as a result of the interaction with the environment is called corrosion. It usually occurs on the exposed surface. If the upper layer of the metal gets corroded, the inner surface of the metal also gets exposed. As a result of this, it tends to continue up to the depth of the metal. The 3 most common types of Corrosions are General Attack, Localized, and Galvanic Corrosion.
Examples of Corrosion
Some of the most common examples of corrosion are:
- Tarnishing of the silver
- Iron being covered with a brittle brown coloured layer
- Brass and copper is covered with a green coloured deposit
- The surface of the aluminium becoming dull and losing its shine
Corrosion Prevention Methods
There are a number of ways to protect the metals from corrosion. Here we’ll discuss some of the most commonly used methods.
By surface coating
You can prevent the corrosion of the metal by coating their surface using any of the following:
- By applying oil, grease, paint or varnish on the surface.
- By coating/depositing a thin layer of any other metal which does not corrode.
For instance, you can prevent the surface of iron from corrosion by depositing a thin layer of chromium, zinc or nickel on it. Similarly, brass or copper can be protected by coating it with a thin layer of tin. In our country, tinning of brass is a very common practice.
By connecting metal to a more electropositive metal
You can also prevent by connecting the metal to a more electropositive metal. As long as the more electropositive metal is present, the given metal will not get corroded. For instance, you can protect iron from corrosion by connecting it to a block/plate of zinc or magnesium. This method of protection is known as cathodic protection.
By forming insoluble phosphate or chromate coating
The third method of prevention is by treating the metal surfaces with phosphoric acid. It forms an insoluble phosphate coating on the surface which protects the metal from corrosion. You can also form a thin chromate layer to prevent the metals from corrosion.
Answer:
what is corrosion?
Corrosion is a deterioration of a material caused by environmental interactions. It is a natural phenomenon, requiring three conditions: moisture, a metallic surface, and an oxidizing agent known as an electron acceptor. The process of corrosion converts the reactive metal surface into a more stable form, namely its oxide, hydroxide, or sulfide. A common form of corrosion is rust.
Corrosion can have a variety of negative effects on metal. When metal structures suffer from corrosion, they become unsafe which can lead to accidents, such as collapses. Even minor corrosion requires repairs and maintenance. In fact, the annual direct cost of metallic corrosion is approximately $2.2 Trillion USD worldwide!
While all metals corrode, it is estimated that 25-30% of corrosion could be prevented using suitable protection methods.
How can we protect metals from corrosion?
•Metal Type. One simple way to prevent corrosion is to use a corrosion resistant metal such as aluminum or stainless steel.
•Protective Coatings. The application of a paint coating is a cost-effective way of preventing corrosion. ...
•Environmental Measures.
•Sacrificial Coatings.
•Corrosion Inhibitors.
Design Modification.