By K.S. Jayaraman. Karnataka, India, 11:02 AM IST
Indian metallurgists have developed a type of corrosion-resistant iron that construction engineers would love. And vital clues for it came for Delhi's famous Iron Pillar that has been standing tall for over 1,600 years.
Developed by Ramamurthy Balasubramaniam and his former student Gadadhar Sahoo of the Indian Institute of Technology (IIT) in Kanpur, the iron contains phosphorus and shows remarkable resistance to corrosion, especially in concrete.
'This is a significant first step in the possible commercial (large-scale) use of these irons,' Balasubramaniam, better known as Bala, told IANS.
Most steels today contain small amounts of carbon and manganese. Modern steel makers avoid phosphorus because its segregation to grain boundaries makes the steel brittle.
But the IIT team successfully produced ductile phosphoric irons by driving the phosphorus away from grain boundaries through clever alloy design and novel heat treatment.
Ironically, Bala's material is not new. It was being made by Indian ironsmiths centuries ago. Bala says he got the clue for developing this material from the six-tonne seven-metre tall Delhi Iron Pillar - a major tourist attraction in the Qutb Minar complex -- that has been standing for centuries in the harsh weather of the capital without any corrosion.
'As a metallurgist, I was intrigued,' Bala told IANS. And his passionate quest to unravel the mystery that began in 1990s has now culminated in phosphoric irons.
The test samples developed by the IIT team remained fresh after three months of being immersed in solution, simulating the corrosive concrete environment, whereas the best commercially available steels got rusted. In another experiment, they embedded the samples in concrete to simulate actual conditions and obtained similar results.
'The work is especially important in regard to the widespread use of steels in civil structures,' said Gerhard E. Welsch, professor of Materials Science and Engineering at Case Western Reserve University (Cleveland, Ohio).
'The recent bridge collapse in Minneapolis has added new urgency,' Welsch said in a congratulatory message to Bala. Seven people died when the bridge across the Mississippi river collapsed Aug 2, 2007.
Current philosophies to tackle corrosion in concrete include the addition of inhibitors to the cement mix, use of rebars that are galvanised, epoxy coated, or micro-alloyed by the addition of small amounts of chromium, copper and nickel -- elements that are known to induce passivity in iron.
Their high cost is a disadvantage, says Bala. 'Besides, we have experimentally shown our phosphoric irons perform better.'
Bala's real break came when he found that the iron used in the Delhi pillar contained elevated amounts of phosphorus -- as much as 0.25 percent against less than 0.05 percent in today's iron. He found this was a result of the ancient process where iron ore is reduced in a single step by mixing it with charcoal, without any limestone addition.
Modern blast furnaces, on the other hand, use limestone yielding molten slag and pig iron (high in carbon) that is later converted into steel. Most phosphorus is carried away by the basic slag.
Further studies and analysing rust from the pillar showed that phosphorus catalysed the formation of a protective passive film on the surface of the pillar that acted as a barrier between the metal and rust.
Tanjore Anantharaman, author of the book 'Delhi Iron Pillar - the Rustless Wonder' and Bala's former teacher at the Benaras Hindu University, says phosphorus was long suspected to be behind the pillar's corrosion resistance. 'It was Bala who proved it.'
That was in 2000. Actual material development and corrosion tests were initiated in 2003 when Sahoo joined Bala for his PhD that he completed in 2006.
'Our papers based on the thesis are coming out now,' Bala said. All the work, he said, was done with institute funds without any external support.
'Certainly, we are not claiming that this is the end of our studies,' admits Bala. 'We have shown the usefulness of phosphoric irons for concrete reinforcement applications. Now it has to be taken up by more researchers for greater understanding.'
Bala thanks his forefathers for the success. 'I am of the firm belief that ancient Indian metallurgists had the empirical knowledge that high phosphorus content ores resulted in corrosion-resistant iron. They did not create this material by accident.'
Most Recent Comments
We are catching up on the scientific DEVELOPMENTS that we had lost during MOGUL empire period.
I thought there is nothing left in Metallurgy for R & D. See now we have Mr.Bala. Great work! Congratulations!
[CONCLUDED]Dynamic collaboration bet. the govt. labs. and industry which has its own R&D labs. never came about in India in any big way. Dr CV Raman it was who said he would rather not, when Nehru called upon him to, take over organizing a network of labs in India with organic bureaucratic links. His nephew, another Nobel Laureate, was highly critical of the deplorable attitudes of politicians and the manner in which the labs were manned and run very unproductively without any direction and time-bound programmes.(In response, he was held in contempt for becoming an American citizen, by some in the higher echelons of govt.R&D!) The government bureaucracy and sycophants in R&D held sway, and the piture of R&D is there for all to see.The issue is thus much bigger. I know several scientists in DRDO labs used to get transfers to near their native places, by pulling wires at the centre. Research Labs which are being set up are shifted to other than the originally intended locations, when the Directors could prevail on the secretaries concerned with some spurious arguments. The question is, where is the motivation in all this for real research ? IIT-ians are in a slightly different situation, but their research results need to be convincingly presented to industy and/or government and when turned into commericalization, the technologies should compete with the imported/ established technologies. Some of our industries are led by the erstwhile mercantile/trading community and they have seldom bothered about dignified indigenous R&D of which we Indians can be proud of.
MR Balasubramaniam's response is well taken. We, as a nation have had numerous highly original thinkers in science and technology, mathematics, astronomy, astrophysics, and civil and materials engineering. The British made us feel very mean of ourselves, but, lo, although numerous R&D centtes/labs were set up since Independence in fulfilment of Jawaharlal Nehru's vision with the objective of making science serve the needs of Indian society and economy, the big blunder committed is that thesee centres are run more like government departments, more procedure- than result- oriented in the sense of patenting and exploiting technologies. This lack of dynamism is not peculiar to our R&D alone, it has been characterizing our industries also, in as much as loved to import technologies throuugh collaborations, but never ever to emulate the highly successful R&D activities in, the US for example. No blame can be laid at the doors of our scientists - since the scientific spark in generation after generation of our young scientists will always shine despite the unimaginative governmental organization of R&D which drives many people to go abroad expecting to not only bring out their best but also get recognition and reward (without illegitimately being shared by others who did not participate but were at the last minute added to the R&D team.) CONTD.
Thanks for the three comments. Here are some of our responses to the points raised:
1. The comments of Mr. Balakrishnan are relevant and this is precisely the mindset wer are against. There is practically no support or excitement in this development because as a nation, we seem to have somehow lost the scientific temper. That much is clear to me after doing work on this subject for 17 years or so. Mr. Balakrishnan makes a remark that going to press must be avoided. We are the last to go to press to announce our work. We are in the serious study of corrosion and materials and therefore all the work that we do is written properly, sent for publication in the topmost journals and only after the matter is properly reviewed and accepted, we disclose anything to "press". In fact, we had known the very good performance of phosphoric irons in concrete reinforcements right in 2005. We did not go about claiming anything that time. We promptly applied for a patent and then worked on the scientific merit of the work and got the papers published and then only we disclosed this to Dr. Jayaraman, when HE ASKED US if there was something interesting that we were doing. Not the other way about, i.e. that we go about contacting the PRESS. I hope this wrong impressing is cleared
India of the past had in vogue many technolgogies using simple techniques and locally available materials. Long-lasting products with anti-corrosion properties were produced, for example, and used in structurals to weather the elemental forces through time, civil engineering e.g. dams. Of course corrupt practices so universal in India today making(many bridges collapse before being fully buil!) were unknown, due to their high sense of duty and fear of God since their end-products were for common good. Of course capital punishment would be expeditiously meted out to those who wanted to cheatiin pubblic works. Now many factors are responsible for suppressing the true latent potential of engineering skills among our people, both formally schooled and others: unresponsive government officials who can understand only commercial or otherwise seldom intricate technical details, corruption due to project advisers' vested interests, unimaginative and outworn government policies re: R&D, and above all, an incapacity of responsible ministers to take a cost-benefit view of indigenous technology development, a demeaning attitude of industrials who want to have it all easy through foreign technical involvement at the expense of indigenous technology, no less than taluk office procedure orientation in our R&D institutions where people work on 9 to 5 routine with no zeal or motivation for being creative. When IITians such as this Kanpur group comes up with news of a technology of their own, it should be studied and any problems like trial projects for use should be financially backed in a sustained manner to see to it that any gaps in the technology are duly filled by a little further R&D work. At the same time, the practice (even adopted by some apex R&D institutions) of going to the press to announce ground-breaking developments which are seldom heard about thereafter in any tangible sense must e eschewed.
Production of steel economically is the first criterion. Secondly, the techni ques like galvanising, epoxy coating etc are already in vogue.No denying that, any steel exposed to corrosive atmosphere will corrode, if not well protected externally. It may also be well remembered that wrought iron placed in a non corrosive atmosphere can go on and on for ever which is what is happening to the iron pillar near Qutb Minar.
I wonder how much role is played by Phosphorus in the preservation of the iron pillar really!
If Bala's & Sahoo's development is directed towards Reinforcement bar production it would be a great service to the society.
Congratulations to the great Young Scientists of India, who are willing to look at our ancient traditions with pride, and devote themselves to make modern scientific investigation to not only revalidate but also revive the great Indian Traditions.
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