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Showing 13 results for Bronze

Hamidreza Bakhshandehfard, Sedighe Taheri,
Volume 1, Issue 1 (4-2017)
Abstract

The objects of the study are two bronze daggers dated back to the late Bronze Age and early Iron Age. They lack any ornaments and there is corrosion and oxidation in their surface. The purpose of this study is to recognize the technological and pathological research on the mentioned objects through comparative and pathological studies and library method, to conduct the technological and pathological research through laboratory method (wet chemistry, radiography, metallography, metal core elemental analysis by Scanning Electron Microscope (SEM), analysis of corrosion by X-ray diffraction (XRD) in order to identify the metal and making techniques and to determine the types of damage, and finally to perform the conservation and restoration of the these objects through the conservation plan.
After studying and conducting experiments mentioned, it was determined that the material of the objects was bronze with carbonate and chloride corrosion. The making methods in these objects is casting and hammering. They were recognized to belong to the Iron Age.

Omid Oudbashi,
Volume 1, Issue 1 (4-2017)
Abstract

Recently risk assessment and management in cultural-historical collections is one of the important subjects in the field of preventive conservation research. Different methods and aspects of are used and studied in the field of risk assessment in archaeological sites and collections and significant results are achieved and published in last decades. One of the types of archaeological collections is metal collections that may be found in archaeological excavations. In this paper, application of risk assessment approach is investigated to estimate conservation condition in archaeological bronze collection. This approach is concentrated on occurrence of active corrosion (bronze disease) and factors influencing it during burial time and post-excavation period. Thus, the results of analyses based on an analytical system is considered that is performed previously (Metal-Environment-Corrosion system) including identification of soil environment, characterization of corrosion mechanism and their effect on conservation condition in bronze objects. For this purpose, two bronze collections are studied that are discovered from Haft Tappeh and Sangtarashan sites from Iran. The condition of two collections is assessed consisting of identification of risks and deterioration factors influencing bronze objects during excavation operation as well as post-excavation preservation and risk assessment based on occurrence of active corrosion in the collections. Finally, conservation condition and excavation procedure and preservation of the collections are estimated and analyzed based on the corrosion mechanism occurred in the objects and results of risk assessment in soil and museum environments.

Parastou Naeimi Taraei, Shaiba Khadir,
Volume 1, Issue 1 (4-2017)
Abstract

Due to the complex corrosion mechanism of the bronze objects, explaining the structure of different layers of corrosion in these objects at microscopic levels is possible. Typically copper oxide(I) is the first corrosion layer on surface of bronze objects that are excavated of historical sites. However, depending on the environmental conditions، various forms of corrosion layer of tin or copper-rich oxide are formed that are effective in corrosion resistance of objects. Identification of tin oxides or copper-tin corrosion products is not simple by using of routine methods of instrumental analysis.However in this research the formation process of copper and tin oxides of some of historical bronze objects of Iran were studied by using the optical microscope with polarized light that show colored corrosion products and in some cases the method of scanning electron microscopy equipped with elemental analysis (SEM-EDX) was used to complete the identification process of oxide layers. According to the results, identify of evidence of differences in distribution of copper and tin in the microstructure that is result of macroscopic and microscopic segregation, formation of a solid solution of copper besides the copper-copper oxide eutectic mixture during the solidification process, the appearance of copper oxide inclusions in the microstructure of metal, moving The tin-rich layer of copper oxide layer to the outside, formation of copper oxide-tin oxide sandwiching layers, selective dissolution of tin in the outer layers, decuprification phenomenon in corrosion layers  and condensation of tin oxides in the center of sample and finally the usual formation or degradation of copper oxide layer under certain conditions have been studied with microscopic imagesof selected samples of bronze objects which confirmed the ability of microscopic techniques in the study of oxide layers of bronze objects.

Mohammad Mortazavi, Ahmad Salehi Kakhki , Mohammad Ali Golozar , Hassan Tala’i ,
Volume 1, Issue 2 (7-2017)
Abstract

One of the most widely used terms in the conservation and restoration of cultural and historical artifacts, particularly in the field of ancient metal objects, is patina. Although, this term is also applied to other historical materials, such as paintings and stones, its frequent used in the context of ancient bronzes makes it essential to develop a clear and accurate understanding of its meaning and implications. From the perspective of the studying deterioration of the artifacts, patina-as corrosion products in bronze artifacts-can significantly impact both the tangible and intangible aspects of the objects. on the one hand, it contributes certain values, such as age and aesthetics. On the other hand, it serves as an important criterion in conservation and restoration practices. However, the lack of comprehensive and precise definition of this term leads to complexity in conservation decision-making. In this paper, based on a literature review, the differing and similarity viewpoints on patina have been investigated. Following this, the term is reviewed in relation to different corrosion morphologies, and issue related to its current definitions are discussed. The different values of the patina are debated, and its role in the principles of conservation is reevaluated. In this field, confusion arising from the application of the term patina in the conservation of archaeological bronzes have been highlighted. Finally, considering the unique properties of corrosion phenomena in archaeological bronzes, the concept of the “original surface” is discussed as an approach to addressing this issue.  

Hamid Fadaei, Majid Ayasi , Parisa Babar Shams Mogouei, Masoud Bater, Kazem Borhani-Ahang, Elahe Khakbaz Alvandian, Mohammad-Saeid Saedi , Roozbeh Shamseh, Reza Sheykh-Al-Eslami, Majid Oloumi , Mahdi Koliaei, Nahid Harati-Ardestani , Reza Hormehr , Soheila Zakavi ,
Volume 1, Issue 4 (3-2019)
Abstract

Archaeological excavations at the ancient site of Haft-Tepe commenced in the winter of 1965 under the direction of Dr. Negahban and continued for fourteen seasons until 1978. These excavations led to the discovery of a significant assemblage of architectural remains and diverse historical artefacts. Among the finds were various ceramic vessels and objects, a collection of clay tablets, seals and seal impressions, a range of bronze artefacts, numerous fragments of painted mud plaster, coffins, stone objects, clay busts, as well as decorative items such as necklaces, plaques, glass vessels, and bone tools. A considerable portion of these artefacts is today preserved in the Haft-Tepe Museum. In response to the quantity and importance of the discoveries, the idea of establishing a museum adjacent to the archaeological site was raised during the second season of excavations. Construction began in 1970 and, upon completion, the museum was inaugurated in the spring of 1973. With the outbreak of the Iran–Iraq War in 1980, the museum was closed; part of its prominent collection was transferred to Tehran, while other objects remained in situ. In the spring of 2001, research and conservation activities were resumed under the auspices of the Chogha Zanbil - Haft Tepe Cultural Heritage Base. One of the first major undertakings during this period was the reorganisation of the museum’s collection, carried out in collaboration with graduate students of conservation from the University of Art, Esfahan. In this process, artefacts that had previously been kept in unsuitable and scattered conditions were collected, classified, recorded, documented, and systematically arranged. This initiative laid a crucial foundation for the long-term preservation and safeguarding of the invaluable heritage of Haft-Tepe.

Narges Doosti Sani, Mahshid Ilkhani, Shaiba Khadir, Afshin Ebrahimi,
Volume 2, Issue 1 (6-2019)
Abstract

The study of metal works of Bam citadel (Arg-e-Bam) is underway to study the pathology of metalworks in Iran.The aim of this project is to study and investigate the corrosion mechanisms of metal objects. Various metallic works including iron, silver and copper alloys have been gained from the area of Arg-e-Bam. The research is focused on a number of bronze works of this historical site.The studies have been done using Microscopic and Macroscopic methods including metallography, wet chemistry, X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). According to dendritic structure of these objects, the results show that most of them have been made in casting method and corrosion products are including Cuprite (Cu2O), Azurite (Cu3(CO3)2(OH)2), Brochantite (Cu4(OH)6SO4), Cassiterite (SnO) and the chloride compounds like Atacamite (Cu2Cl(OH)3), Paratacamite (Cu2Cl(OH)3, Nantokite (CuCl) and Melanothallite (Cu2OCl2). The noticeable point is that there are inclusions containing iron and sulfur in all specimens that represent the using of sulfide ore in copper extraction process.
 
Faramarz Azadbakht, Mohammad Mortazavi,
Volume 2, Issue 2 (9-2019)
Abstract

Understanding ancient metallurgy is achieved through the study and analysis of metal artifacts and evidence related to extraction and metalworking processes. Examining metal objects provides valuable information about the type of metal or alloy used, manufacturing and decoration techniques, and, in some cases, the type of ore employed. Therefore, analyzing alloy composition and forming techniques is of great importance in archaeometallurgy. This article presents a technical investigation of a bronze lion figurine from the Yazd Museum collection, obtained through illicit excavations. Alloy composition analysis was conducted using Atomic Absorption Spectroscopy (AAS), and X-ray imaging was employed to investigate the construction method. The results revealed that the figurine is made of a copper-tin alloy (bronze) with the presence of lead. Radiographic images indicated that the figurine is hollow, with its front rod extending into the internal section. Based on these findings, it was determined that the figurine was crafted using the lost-wax technique. Furthermore, the probable shape of the mold used, the manufacturing stages, and its various components are proposed.

Hossein Farahmand Boroujeni, Hamidreza Bakhshandehfard,
Volume 2, Issue 2 (9-2019)
Abstract

Each alloy, depending on its constituent metallic elements, manufacturing process, and degradation mechanisms, exhibits unique characteristics. Studying the structure and composition of museum metal artifacts assists researchers in identifying similarities and differences among objects based on various criteria, contributing to a better understanding of the evolution of historical-cultural artifact production techniques. Additionally, such studies enable the identification of internal and external causes and conditions of alloy degradation, paving the way for preventive measures to mitigate or halt deterioration. This research focuses on the technical study and damage assessment of a bronze vessel from the Samavi Collection at the Esfahan Museum of Decorative Arts. Data collection was conducted through library research, and the analogical method was employed for comparative studies. Furthermore, experimental methods including chemical tests, X-ray diffraction, scanning electron microscopy, and radiography were applied to the artifact. This article examines the role of each of these methods and critiques the analogical approach in comparative studies. Based on the results, the artifact is attributed to the region spanning Luristan to Syria and dated to the 7th to 8th centuries BCE. Additional findings include the approximate composition of the artifact’s elements, the use of molding and hot-working techniques in its production, and the identification of carbonate deposits.

Ramin Talei, Parastoo Naeimi Taraei,
Volume 2, Issue 2 (9-2019)
Abstract

With the advent of Islam, bronze temporarily replaced gold and silver in the production of metal vessels. Among the bronze artifacts used during this period, high-tin bronze (white bronze) objects, valued for their silver-like appearance, gained significant attention. One such artifact is a vessel discovered during debris removal operations following the 2003 Bam earthquake, located in the southern part of the Bam Citadel, specifically the southern section of the house known as Mir Akbar. Similar decorative patterns are found in artifacts from the Seljuk and Timurid periods. In this study, the artifact was examined using X-ray imaging, and microstructural analysis of a sample from the vessel’s base was conducted using reflected light optical microscopy after preparation. To further the technical investigation, Scanning Electron Microscopy (SEM) equipped with Energy-Dispersive X-ray Spectroscopy (EDX) was employed to analyze the alloy composition and metallic and non-metallic phases. The results indicate that the vessel was produced through casting, with directional mechanical work causing elongation of non-metallic sulfide phases within the metal matrix. The microstructure of the vessel consists of single copper-rich grains dispersed in a needle-like beta phase rich in tin, characteristic of high-tin bronze (white bronze). After cooling, the alloy underwent heat treatment at approximately 650°C followed by rapid quenching, leading to the formation of the needle-like phase and resulting in the vessel’s hardness and brittleness.

Hamid Reza Bakhshandehfard, Hosna Rabeie,
Volume 3, Issue 1 (6-2020)
Abstract

The cemetery of the Pardis Tepe, located in Qarchak of Tehran province, is a valuable historic landmark of the Iron Age which has been discovered in the excavations of these bronze wire objects. Despite the historical importance of the metal objects discovered in Tehran, no independent research has been carried out on the metal objects obtained from this site, in terms of technological and pathological aspects, using laboratory and methodological methods. The aim of this paper was to study a bronze rod found in Tepe Pardis, in terms of species and application, regarding technical questions about elemental combinations and the method of making and technological position of the study area. For this purpose, instrumental analysis methods such as AAS, SEM-EDS were used to identify the alloying technique, the chemical composition of the alloy, and metallography to identify the manufacturing method. Historical studies of the object attributed it to the Iron Age. Based on elemental data analysis, the composition used to make copper-tin alloy objects (bronze) and microstructure analysis by metallography, these objects were made by continuous thermal / mechanical operations. Depending on the results of the XRD test, cuprite, malachite and nantokite compounds were identified in corrosion products. Due to the significant presence of Nantokite, it can be said that the object has active corrosion.

Seyed Iraj Beheshti, Sheyda Ashrafi, Siamak Sarlak,
Volume 5, Issue 3 (12-2022)
Abstract

Petrographic studies play a significant role in understanding the structural characteristics and compositions of ceramic artifacts, contributing to the identification of cultural transformations and exchanges based on technical changes in these objects. As such, it is consistently a central component of studies on analyzable artifacts. The archaeological site of Qoli Darvish, located 3 km south of the city of Qom, spans over an area of approximately 30 hectares and contains valuable archaeological remains, including distinctive types of pottery ranging from the Early Bronze Age to Iron Age I. In this study, aimed at investigating the texture, components, and classification of the pottery, 37 pieces of ceramic artifacts discovered during the 2015 excavations were analyzed. Thin-section petrographic analysis, focusing on identifying microscopic structures and existing minerals, was used for this purpose. The results revealed three distinct textures in the pottery samples: coarse-grained heterogeneous or porphyritic texture, fine-grained or silty texture, and clastic texture. The clay matrix of these ceramics shows minimal sorting of its components and contains grog and coarse fillers. Various igneous rock fragments, grog (remnants of silt, clay, or crushed ceramics), calcite, and quartz are visible in the samples. Based on the findings, it can be concluded that the materials used in the production of these ceramics were generally local and sourced from the surrounding region.

Tahereh Shihebori, Elahe Khakbaz Alvandiyan,
Volume 6, Issue 1 (6-2023)
Abstract

Historical monuments have always had a special place in historical-cultural studies as one of the indicators of identifying the cultural heritage of nations. The following paper aims to present a report on the restoration andconservation of metal objects of the cultural heritage treasure of Yazd city. Protection of this treasure which is one of the richest collections in terms of the variety of historical works, which put the restoration and conservation of the present objects on the agenda in the past years, and restoration and conservation operations were carried out on these valuable works. For this purpose, an effort was performed in this research during 7 years at different times to select metal objects with special features from this rich collection, and its report is presented in this article. Various types of objects such as silver, iron, and bronze objects were restored and protected. Improper maintenance conditions in the past have caused these works to be covered by environmental sediments or corrosion products, which sediments and corrosion products cause the illegibility of designs and patterns and sometimes the complete destruction of objects. So, in the operation procedure of restoration and conservation observing theoretical principles, cleaning operation was done as far as possible mechanically and chemically if needed. Low percentages of consumable materials were used and materials were selected that do not harm the environment as much as possible. The most important step after the restoration operation is the conservation of objects in desirable conditions and periodic reviews, so that if any damage is observed, it should be repaired immediately. The following paper describes the steps of restoration and conservation of metal objects of different types and protects them to keep them in standard conditions to be shown in the museum.
 
Fatemeh Alamirzaei, Parasto Naeimi Taraei,
Volume 7, Issue 3 (11-2024)
Abstract

The study of corrosion mechanisms in ancient bronze artifacts, particularly those from the salty and humid region of Hormuz, is crucial due to severe corrosion. This article examines a bronze dagger attributed to excavations in Hormuz to analyze its corrosion behavior influenced by the environment. Techniques such as X-ray imaging, stereomicroscopy, X-ray diffraction (XRD), polarized light microscopy (PLM), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) were employed. Results show that most of the dagger has transformed into corrosion products, including copper and tin oxides, as well as basic chloride compounds like atacamite and paratacamite, forming a three-layered corrosion structure. The corrosion mechanism involves selective dissolution of copper, its migration to outer layers, and the concentration of tin oxide compounds in the central regions, accompanied by chloride ion penetration. This process has preserved patterns of grain structure and thermal twinning in the inner oxide layers, with periodic deposition of copper and tin oxides indicating the formation of a colloidal solution of copper and tin salts beneath the soil (Scott, 2002; Robbiola et al., 1998).


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