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.
Dr Hamidreza Bakhshandehfard, Ms Masoom Tafreshi Fami Tafreshi, Dr Mohammadamin Emami, Volume 9, Issue 2 (9-2026)
Abstract
When dealing with historical bronze artifacts, we usually encounter a layer called patina on the surface of these artifacts. Understanding the nature, structure, and function of this layer is one of the fundamental issues in the field of conservation and restoration of historical metalsIn general, patina in metals is defined as a coating consisting of various chemical compounds such as oxides, carbonates, sulfides, and chlorides, which forms as a result of the long-term interaction of the metal with environmental and corrosive factors.The question of what role patina plays in the conservation, historical interpretation, and restoration decisions of bronze objects has provided the main motivation for the present study to investigate and scientifically understand this phenomenon.In this article, while introducing the concept of patina and its types in historical bronzes, we examine the factors affecting the formation and evolution of this layer, including environmental conditions and alloy composition.
