expressindia.indianexpress.com
expressindia web
HomeBlogsCricketAstrology ShoppingTendersClassifieds Reader Comments
Font Size
Expressindia » Story

Mystery of Delhi's Iron Pillar unraveled

Press Trust of India

Posted: Jul 18, 2002 at 1500 hrs IST

Experts at the Indian Instituteof Technology have resolved the mystery behind the 1,600-year-old iron pillar in Delhi, which has never corroded despite the capital's harsh weather.

Metallurgists at Kanpur IIT have discovered that a thin layer of "misawite", a compound of iron, oxygen and hydrogen, has protected the cast iron pillar from rust.

The protective film took form within three years after erection of the pillar and has been growing ever so slowly since then. After 1,600 years, the film has grown just one-twentieth of a millimeter thick, according to R. Balasubramaniam of the IIT.

In a report published in the journal Current Science Balasubramanian says, the protective film was formed catalytically by the presence of high amounts of phosphorous in the iron—as much as one per cent against less than 0.05 per cent in today's iron.

The high phosphorous content is a result of the unique iron-making process practiced by ancient Indians, who reduced iron ore into steel in one step by mixing it with charcoal.

Modern blast furnaces, on the other hand, use limestone in place of charcoal yielding molten slag and pig iron that is later converted into steel. In the modern process most phosphorous is carried away by the slag.

The pillar—over seven metres high and weighing more than six tonnes—was erected by Kumara Gupta of Gupta dynasty that ruled northern India in AD 320-540.

Stating that the pillar is "a living testimony to the skill of metallurgists of ancient India", Balasubramaniam said the "kinetic scheme" that his group developed for predicting growth of the protective film may be useful for modeling long-term corrosion behaviour of containers for nuclear storage applications.

Print
 
Post Comments
Name* Email ID*
Subject* Country*
Message*
Characters remaining
 
TERMS OF USE: The views, opinions and comments posted are your, and are not endorsed by this website. You shall be solely responsible for the comment posted here. The website reserves the right to delete, reject, or otherwise remove any views, opinions and comments posted or part thereof. You shall ensure that the comment is not inflammatory, abusive, derogatory, defamatory &/or obscene, or contain pornographic matter and/or does not constitute hate mail, or violate privacy of any person (s) or breach confidentiality or otherwise is illegal, immoral or contrary to public policy. Nor should it contain anything infringing copyright &/or intellectual property rights of any person(s).
I agree to the terms of use.

Latest News

Business

Showbiz

Sports

Akhilesh defends IAS officer's suspension, Centre says justice will be done

Political parties object to Supreme Court order on convicted legislators

Dominant India march to 4-0

CBI gives clean chit to Raja Bhaiya in DSP murder case

2G: Supreme Court slams I-T dept, CBI for not acting on Radia tape information...

4 militants killed by Army in Kashmir

Ishrat case: Accused cops demand more documents from CBI

More
© The Indian Express Limited. All rights reserved
Advertise With Us | Privacy Policy | Feedback | Express Group | Site Map