ISSN: 2067-533X INTERNATIONAL JOURNAL OF CONSERVATION SCIENCE Volume 9, Issue 2, April-June 2018: 277-290 www.ijcs.uaic.ro AN INVESTIGATION OF THE CORROSION BEHAVIOR OF SOME IRON ARTIFACTS BELONGING TO THE EARLY IRON AGE Parastou NAEIMI TARAEI 1* , Abolghasem DOLATI 2 , Mohammadamin EMAMI 1 1 Department of Conservation of Artifacts, Art University of Isfahan, Isfahan, Iran. 2 Department of Material Science and Engineering, Sharif University of Technology, Tehran. Iran. Abstract The corrosion process of two iron dagger handles decorated with bronze strips found from the Ziviyeh area, which is one of the important Iron Age sites in the northwest of Iran, is thoroughly investigated. X-ray radiography was used to obtain the damages and corrosion zones of the artifact. Optical and scanning electron microscopies were used to study the microstructure of cross sections and to achieve structural details about the metal matrix and corrosion layers. The X-ray diffraction method was used to study the chemical characterization of corrosion products. The results of studies have shown that severe stress on bronze strips is caused by the formation of goethite and lepidocrocite compounds and their increased volume. Stress corrosion along the inter granules and cracking in some of the bronze strips are observed. The created cracks in the magnetite layers provided shortcuts to transfer the moisture and corrosive anions. The atmospheric corrosion of the remaining ferrous parts continued actively by dewatering corrosion products and creating wet blisters and holes filled with oxyhydroxide products. The formation of oxide compounds of copper and tin on the surface of bronze strips followed a slow process of uniform corrosion in bronze strips to a limited extent. Keywords: Corrosion; Iron–bronze bimetallic artifacts; Early Iron Age; Iran; Ziviyeh Introduction The corrosion of copper and bronze artifacts is being studied for many years. Since 1826, when a helmet was found in the sea and red oxide products of cuprite and copper were identified as a result of the process of redeposition of copper [1], the corrosion behavior on the historical artifacts has been studied by many scientists. The formation of the cuprite and its effect on the continuation of the corrosion behavior have been addressed in various studies [2-5]. In addition, the patina of ancient bronze can also indicate different forms of tin-rich corrosion layers depending on environmental conditions [6, 7]. Similar studies have been conducted on Iranian bronze artifacts. The obtained results about the dissolution process and the extraction of copper during the decuprification process are examples of these studies on ancient bronze objects belonging to Haft Tappeh historic site, Khuzestan, Iran [8]. In addition, due to the formation of the galvanic cell, copper is protected in contact with the more active metals, including iron, and this process can be predicted in the iron–bronze bimetallic artifacts. The construction of iron–bronze bimetallic artifacts at the beginning of the Iron Age in the north, northwest, north-central, and central Zagros regions, Iran, is one of the techniques used in the manufacture of metal artifacts [9]. The examples of iron artifacts from Central Zagros of Iran * Corresponding author: p.naeimi@aui.ac.ir