Characterization of Corrosion Behavior of Archaeological Iron Spear from Sanur (300 BC – 50 AD) – A Megalithic Site in Southern India

Open access

Abstract

This investigation deals with the chemical composition and microstructural analysis of the iron object, a spear excavated from Sanur, Tamil Nadu- a megalithic site dated 300 B.C. to 50 A.D. Phase analysis and microstructural examination were carried using XRD, optical and variable pressure scanning electron microscope (VP-SEM). Optical micrograph shows the equiaxed grain structure along with the Newman bands. Formation of Newman bands suggests that the original artifact was forged at high temperature followed by cooling, although not so rapid to produce the marked hardening. The absence of carbides at the grain boundary, within the grains and lower value of micro-hardness indicates that the iron spear was not subjected to the carburizing treatment. Results of corrosion characterization revealed that deterioration of excavated iron artifact is associated with the presence of chlorine in corrosion products. However, compact nature of the outer rust (goethite) was helpful in protecting the object. The formation of goethite [∝-FeOOH] layer may prevent the iron matrix suffering from attacks by other environmental factors due to its good continuity. In addition, less aerated environment of storage and no history of any cleaning of object were also helpful in preventing the iron spear from further deterioration.

[1]. Narasimhaiah, B. (1980) Neolithic and Megalithic Cultures in Tamil Nadu, Sindeep Prakashan, Michigan, USA.

[2]. Moorti, U.S. (1994) Megalithic Culture of South India: Socioeconomic Perspectives, Ganga Kaveri Publishing House, Michigan, USA.

[3]. Park, J.-S., and Shinde, V. (2013) Iron technology of the ancient megalithic communities in the Vidarbha region of India. J. Archaeol. Sci., 40 (11), 3822–3833.

[4]. Rajan, K. (Kara. G. (1994) Archaeology of Tamilnadu (Kongu Country), Book India Publishing Company, Tamil Nadu.

[5]. Rao, B.K.G. (1972) Megalithic culture in south India, [Mysore]: Prasaranga, University of Mysore, Michigan, USA.

[6]. Soundara Rajan, K. V (1959) Sanur 1950 and 1952: A megalithic site in District Chingleput. Anc. India, 15, 4–42.

[7]. Banerjee, N.R. (1966) Amirthamangalam 1955: A Megalithic urn-burial site in district Chingleput, Tamilnadu. Anc. India, 22, 3–36.

[8]. Ghosh, M.K. (1963) The Delhi iron pillar and its iron. NML Tech. J., 5 (1), 31–45.

[9]. Banerjee, N.R. (1965) The Iron Age in India Delhi, Munshiram Manoharlal, New Delhi.

[10]. Chen, J.F., Frankel, G.S., Jiang, J.T., Shao, W.Z., and Zhen, L. (2014) Effect of age-forming on corrosion properties of an Al- Zn- Mg- Cu alloy. Mater. Corros., 65 (7), 670–677.

[11]. Sasisekaran, B. (2004) Iron industry and metallurgy: A study of ancient technology, New Era Publications, Michigan, USA.

[12]. Singh, R.N., and Merkel, J.F. (1999) Scientific Studies of Some Iron Objects from Senuwar. Prāgdhārā J. UP State Archaeol. Organ., 123.

[13]. Singh, R.N. (2007) Aspects of archaeometallurgy in South and South-East Asia: a study of metal objects from North India and Thailand, Kala Parakashan, Michigan, USA.

[14]. Narain, A.K., and Roy, T.N. (1976) Excavations at Rajghat, Part I, in Varanasi: Banaras Hindu Univ. Narain Excavations at Rajghat, Part I, vol. 1, Banaras, pp. 74.

[15]. Srinivasan, S., and Ranganathan, S. (2004) Wootz Steel–Legendary Material of the Orient. Indian Inst. Sci. Bangalore.

[16]. Srinivisan, S., and Srinivasa, R. (1997) Metallurgical Heritage of India. Golden Jubil. Souvenir, 29–36.

[17]. Ranganathan, S., and Srinivasan, S. (2006) A tale of Wootz steel. Resonance, 11 (6), 67–77.

[18]. Greaves, R.H., and Wrighton, H. (1924) Practical microscopical metallography, Chapman & Hall, Limited, London, UK.

[19]. Dillmann, P., and Balasubramaniam, R. (2001) Characterization of ancient Indian iron and entrapped slag inclusions using electron, photon and nuclear microprobes. Bull. Mater. Sci., 24 (3), 317–322.

[20]. Saheb, M., Neff, D., Dillmann, P., Matthiesen, H., Foy, E., and Bellot-Gurlet, L. (2009) Multisecular corrosion behaviour of low carbon steel in anoxic soils: characterisation of corrosion system on archaeological artefacts. Mater. Corros., 60 (2), 99–105.

[21]. Dillmann, P., Balasubramaniam, R., and Beranger, G. (2002) Characterization of protective rust on ancient Indian iron using microprobe analyses. Corros. Sci., 44 (10), 2231–2242.

[22]. Selwyn, L.S., Sirois, P.I., and Argyropoulos, V. (1999) The corrosion of excavated archaeological iron with details on weeping and akaganeite. Stud. Conserv., 44 (4), 217–232.

[23]. Turgoose, S. (1993) Structure, composition and deterioration of unearthed iron objects. Curr. Probl. Conserv. Met. Antiq., 35–52.

[24]. North, N.A. (1982) Corrosion products on marine iron. Stud. Conserv., 27 (2), 75–83.

[25]. Chandler, K.A., and Stanners, J.. (1966) Rusting in air - characteristic properties of natural rusts, in 2nd International Congress on Metallic Corrosion, Houston, pp. 325–333.

[26]. Jones, D.A. (1993) Principles and prevention of corrosion. Mater. Des., 14 (3), 207.

[27]. Knight, B., and Knight, B. (1982) Why do some iron objects break up in store. Conserv. iron. Greenwich, Natl. Marit. Museum, 50–51.

[28]. North, N.A., and Pearson, C. (1978) Washing methods for chloride removal from marine iron artifacts. Stud. Conserv., 23 (4), 174–186.

[29]. Gilberg, M.R., and Seeley, N.J. (1981) The identity of compounds containing chloride ions in marine iron corrosion products: a critical review. Stud. Conserv., 26 (2), 50–56.

[30]. Zise, W., Chunchun, X., Xia, C.A.O., and Ben, X. (2007) The Morphology, Phase Composition and Effect of Corrosion Product on Simulated Archaeological Iron1. Chinese J. Chem. Eng., 15 (3), 433–438.

[31]. Refait, P., Drissi, S.H., Pytkiewicz, J., and Génin, J.-M. (1997) The anionic species competition in iron aqueous corrosion: role of various green rust compounds. Corros. Sci., 39 (9), 1699–1710.

[32]. Singh, V. (2012) Studies in composition, microstructure and corrosion characteristics of iron based heritage artifacts.

Journal Information

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 63 63 40
PDF Downloads 64 64 39