A Establishment and Evaluation of a Conservation Treatment for Old Coins Attacked with Bronze Disease, mainly caused by Atacamite.

点击翻译按钮获取中文摘要

1. Analysis of corrosion products on excavated old Islamic coins :The X-ray diffraction analysis of the corrosion products that were brought back to Japan showed that the coins had active bronze dise-ase, mainly caused by Atacamite.2. Choice of cleaning agent :It was imposible to remove the rust by useing mechanical methods because of the number of coins and the short period available for treatment. Therefore chelating agents were required for chemical treatment, which have been used recently for the removal of corrosion products of the copper alloy.From the experiment, it became clear that the Gluconic acid chelating agenent was suitable for long period steeping, and EDTA・3Na was good for short period steeping.3. The effects of treatment by desalting and stabilization depending on the difference of corrosion products :1000 coins were classified into 9 types according to their surface corrosion products, and 30 typical coins were selected from each type. These were examined to see the effects of desalting and stabilization. The results made clear that the corrosion products attacked with bronze disease should be removed as much as possible.4. The evaluation method for conservation treatment :The amount of agents and chloride remaining was checked by measuring the water with pH, sodium ions and chlorine ions that the coins were washed in. The effect of the treatment was measureed by examining the coins after putting them under high humidity.A guide for conservation treatment process :The guide is made for beginners who would like to do this treatment, and who would like to ensure proper application of the treatment.