Iron mask
ever wondered why the 1,600-year-old iron pillar located near Delhi's Qutab Minar has never got corroded despite harsh weather conditions? Metallurgists at the Indian Institute of Technology (iit), Kanpur, have recently found the reason behind this. They have discovered that a thin layer of misawite, a compound of iron, oxygen and hydrogen, has protected the pillar from getting corroded. The protective film started forming after three years of the pillar's erection and has been growing ever so slowly since then. After 1,600 years, the film has grown one-twentieth of a millimetre thick. "The film was formed catalytically by the presence of high amounts of phosphorous in the iron