A new scientific study using advanced nanotechnology sensors has revealed the secret behind the corrosion resistance of the 1,600-year-old Iron Pillar of Delhi. Researchers found that the pillar is coated with a thin, crystalline layer of misawite, an iron oxyhydroxide, which was formed through a specific metallurgical process known to ancient Indian blacksmiths. This layer acts as a self-healing barrier against environmental degradation.
The study highlights the advanced knowledge of metallurgy in Gupta-era India, where craftsmen intentionally controlled the phosphorus content of the iron to promote the growth of this protective layer. These findings could lead to the development of new, eco-friendly anti-corrosive coatings for modern infrastructure.