Chemical Composition of Russian Copper Coins of the Imperial Period

The article is devoted to the study of the chemical composition and assessment of the quality of the metal of Russian copper coins of the 18^th–early 20^th centuries. Coins of this period are common in museum and private collections. However, the problem of metal purity and features of its composition is practically not covered. These issues are of interest for understanding the development processes and assessing the state of the Russian non-ferrous metallurgy in this period and, in particular, the Ural copper industry, since this industry has been and still remains one of the leading ones in the Ural and a significant part of Russian copper coins were minted in Yekaterinburg. To determine the chemical composition of coin metal, a non-destructive method of metal analysis, X-ray fluorescence analysis, was used in the work. At the same time, the problem of the presence of a corrosive layer on the surface of coins, the removal of which is not always possible for reasons of the preservation of the artifact, is solved. A method for using X-ray fluorescence analysis is proposed taking into account the phase composition of the surface layer. It is shown that the purity of copper remained above 99% in the studied sample of coins, which characterizes the high level of the Russian copper industry in the 18th-19th centuries. The presence of natural micro impurities of various composition and concentration in copper indicates the use of metal from various sources. The paper shows the effectiveness of using X-ray fluorescence analysis to determine the chemical composition of the metal of coins, which contributes to a more complete attribution of artifacts. The approaches developed in this work can be useful in the study of artifacts based on copper alloys.