Iron Victory Pillar,Delhi (4th CE).w.ispatguru.com |
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ron Victory Pillar,Delhi (4th CE)delhitourism.travel |
The Iron Pillar in the Qutb complex of Delhi, a testament to ancient Indian metallurgy, stands as an enigmatic marvel dating back to the 4th century CE. This Delhi Iron Pillar, with no cover over it, has withstood the vagaries of weather for 1700 years continuously with no sign of rusting so far. This towering victory pillar, forged from a unique iron composition, measures 23.08 feet in height with a diameter of 17 inches at its base, tapering to 12 inches at its top. Weighing 6.3 tons, the pillar was designed with remarkable stability—its base, buried 3 feet and 8 inches underground, is set on a grid of iron bars soldered into the stone pavement, providing a firm foundation for the centuries it has endured. It still attracts lots of archaeologists and metallurgists, a marvel in metallurgical processes followed in ancient India.
Iron Victory Pillar,Delhi (4th CE). en.wikipedia.org |
Above image: The iron pillar is in the courtyard of Quwwat-ul-Islam Mosque. Its rust-free state has prompted extensive studies, with Archaeologists and metallurgists stated about the rust-free condition of the old iron tower: It is "a testament to the skill of ancient Indian blacksmiths." The pillar's resilience is due to a unique chemical composition with its high phosphorus content, which form a protective crystalline iron hydrogen phosphate layer on the surface. This layer shields it from corrosion, withstanding the effects of both rain and sunlight for centuries in this hot city........
The Iron pillar Delhi, en.wikipedia.org |
What astonishes scientists and historians alike is the pillar's exceptional resistance to rust, despite being exposed to Delhi's harsh weather conditions for 1,700 years. Its rust-free state has prompted extensive studies, with archaeologists and metallurgists recognizing it as "a testament to the skill of ancient Indian blacksmiths." The pillar's resilience results from a unique chemical composition, particularly its high phosphorus content, which leads to the formation of a protective crystalline iron hydrogen phosphate layer on the surface. This layer shields it from corrosion, withstanding the effects of both rain and sunlight.
Professor R. Balasubramaniam of the Indian Institute of Technology, Kanpur, has highlighted the specific factors contributing to this corrosion resistance. He explains that a passive protective film forms at the interface between the iron and any rust, owing to the presence of second-phase particles like slag and un-reduced iron oxides within the iron's microstructure. The high phosphorus content and alternating wet and dry conditions further aid in forming this film, offering the iron pillar an enduring defense against oxidation.
Interestingly, later inscriptions dating to 1052 CE, during the rule of the Tomara king Anangpal II, suggest the pillar may have been relocated from its original site, possibly Udayagiri, by the Tomar king Vigraha Rāja. While its exact origins remain debated, with some scholars proposing 402 CE as its forging date under the Gupta dynasty, this iron pillar continues to captivate experts as a relic of remarkable metallurgical innovation, and it stands resilient as an artifact of India's rich scientific heritage.
''On the Corrosion Resistance of the Delhi Iron Pillar, R. Balasubramaniam, Corrosion Science, Volume 42 (2000) pp. 2103–2129''. "Corrosion Science" is a publication specialized in corrosion science and engineering.