Question

Why is iron pillar rust free?

Answer 1

Rust:

• When iron is exposed to air for an extended time, it oxidizes and creates a reddish-brown iron oxide on its surface.
• Rust is a reddish-brown material, and the process of rust formation is known as rusting.

Iron pillar rust-free:

• The iron pillar is not rusted because it was made of 98% wrought iron.
• Due to the presence of high amounts of phosphorus (as much as 1 percent against less than 0.05 percent in today’s iron) and the absence of sulphur/magnesium in the iron are the main reasons for its remaining rust-free for a long time.
• A thin layer of a˜misawitea, a compound of iron, oxygen and hydrogen, has also protected the pillar.