Application of electrochemical methods to assess the stability and investigation of factors influencing the ancient copper-arsenic artefacts from 3rd Millennium BC

Abstract

The Bazman district constitutes one of the four regions of Iranshahr in the Sistan and Baluchistan province southeast of Iran. This study examines the behavior of arsenic copper alloy deterioration in chloride environments. Electrochemical methods were used to investigate the corrosion rate of some laboratory-made of Cu-As coupons versus five antique As-alloys from Spidej Cemetery in Bazman. Tafel plots (LSV) were used to determine corrosion rate, corrosion current density, and Cyclic voltammetry method for oxidation conditions. The data obtained by the (LSV) method show that the corrosion rate is variable in different concentrations. Electrochemical investigations were conducted on the pH of the soil solution in the area. The results of cyclic voltammetry data show the occurrence of pitting corrosion in the pH solution caused by the burial conditions of the Spidej over time. The behavior of chlorides on the corrosion of these alloys was investigated via soil solution sampling of Spidej Bazman at pH 10.85 with both manufactured and ancient alloys. Four types of corrosion morphology were identified in the arsenic bronze objects. To test corrosion behavior, the linear sweep voltammetry (LSV) technique was achieved. Electrochemical testing using line scan voltammetry demonstrated that the rise in chloride promotion efficiency led to greater migration of the arsenic element from the alloy. At pH 10.17 and 10.85, the minimum corrosion rate for laboratory-made alloys is similar to ancient alloys. Different percentages of the alloy showed different corrosion rates.