Scientists at IIT develop corrosion-resistant iron
Indian scientists have developed a type of corrosion-resistant iron similar to used in Delhi's famous Iron Pillar This work of development was undertaken by Ramamurthy Balasubramaniam and Gadadhar Sahoo of IIT Kanpur. This iron is resistant to corrossion & is likely to find wide application for construction.
The team at IIT developed ductile phosphoric iron by moving phosphorus away from grain boundries by proper alloy design & heat treatment. The team got inspiration to develop the iron from the old & famous iron pillar of Delhi which is subjected to harsh weather for centuries without showing any signs of corrossion.
According to Mr Welsch, professor of Materials Science and Engineering at Case Western Reserve University (Cleveland, Ohio). the work is especially important in regard to the widespread use of steels in civil structures.
The team at IIT observed that the iron used in the Delhi pillar contained phosphorus to the extent of 0.25 % against less than 0.05% in commercially available iron. They found this was a result of the old process where iron ore is reduced in a single step by mixing it with charcoal, without any limestone addition. Whereas in blast furnaces in use today, limestone is used producing pig iron & slag. This pig iron is high in carbon content which is later converted into steel while phosphorus is carried away by slag. Higher content of Phosphorus also contributes in forming protective layer on the surface which retards corrossion.
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