Question

The iron pillar of Mehrauli, Delhi is known as the magic pillar. What is the reason for it not being rusted?

Answer 1

Hint : In order to answer this question, to know the reason for the iron pillar of Mehrauli not being rusted, we will first discuss the exact reason behind it not being rusted. And then we will also discuss the process to prevent the iron from rusting.

Complete Step By Step Answer:
An iron pillar near the Qutub Minar in Mehrauli, in Delhi, was built by an ironsmith circa 400 BC. This iron pillar stands 8 metres tall and weighs 6 tonnes. Even after centuries, the pillar is in good condition and has not rusted. This demonstrates that our forefathers devised a method to prevent rusting. According to studies, it has a layer of iron oxide on its surface.
At the moment of its development, they had mingled phosphorus. It had been painted with a mixture of different substances and had been exposed to a lot of heat. Apart from Delhi, antique metal work may be seen in the Sun temple in Konark in Odisha; Mookambika temple in Kollur, Karnataka; and Dhar, Madhya Pradesh.
Iron and its alloys are widely utilised in the building of a wide range of structures, as well as in a wide range of equipment and objects. As a result, iron corrosion avoidance is quite vital. The following are some preventative measures:
Some iron alloys are rust-resistant. Stainless steel (which has a coating of chromium(III) oxide) and weathering steel are two examples.
When compared to conventional steel, COR-TEN steel rusts at a slower pace. The rust in this alloy provides a protective layer on the alloy's surface, preventing additional corrosion.
Galvanization is the process of coating a metal with a protective layer of zinc. It is a standard way of protecting iron from rusting. This can be accomplished by either dipping the metal to be protected in hot, molten zinc or electroplating it.
$*$ It has been shown for 150 years that coating iron and steel with molten zinc protects them from corrosion.
$*$ The zinc coating protects the part's surface from corrosion and weathering by shielding it from the elements.
Galvanization extends the life of steel parts by establishing a membrane between the metal and the air, which prevents iron oxide from developing on the steel layer. Galvanization also provides greater corrosion protection to parts that are exposed to the elements.
The galvanizing process consists of three basic steps, namely:-
(i) Surface preparation
(ii) Fuxing
(iii) Galvanizing.

Note :
Galvanizing protects against rust in several ways: It acts as a barrier, preventing corrosive chemicals from reaching the steel or iron beneath. The zinc acts as a sacrificial anode, meaning that even if the coating is damaged, the exposed steel is still protected by the zinc that remains.