Historical Articles

August, 1953 issue of Plating

 

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Metal Plating by the Egyptians

*Excerpt from the article, ”Chemistry and Art”, by Dr. C. G. Fink. Reprinted through the courtesy of the American Chemical Society which published the material in its publication, Industrial and Engineering Chemistry, in February, 1934.

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Although the application of thin foils of gold and silver to articles of copper and bronze was known to the ancients, as many museum specimens testify, it was only a few years ago that it was discovered that the Egyptians knew how to deposit a film of antimony on copper by chemical methods. It came about in the cleaning of an ewer and a basin of the fifth or sixth dynasty (about 2500 to 2000 B.C.) belonging to the Egyptian Department of the Metropolitan Museum of Art. During the cleaning operation a white, silvery plating was found on the surface of both the ewer and the basin and, on careful analysis, also found present in this coating was a small amount of iron. The assumption that the antimony might have been applied by a fire process was soon dispelled and the presence of the iron gave a clue.- After numerous trials, starting with those chemicals available to the Egyptians five thousand years ago, it was possible to reproduce this antimony plate on copper by either of the following two methods: Method 1 used 20 grams of ”natron”, 1 gram of antimony sulfide, and 100 cc of water.

The natron was artificially made according to an average of the analyses given by Lucas. The solution of natron and antimony sulfide was brought to boiling and pieces of bright copper were immersed in it. Within a short time, a silvery coating was deposited on the copper. This deposit took a good polish on a cotton buff. The reaction is probably due to interaction between metallic copper and sodium thioantimonite. The plate is relatively hard; evidence of this is shown also in the fact that the antimony bottoms of the ewer and basin had not worn off during the life of the articles before they were buried in a tomb thousands of years ago, and both articles showed much wear, so that they were evidently not new when put into the grave where they were found.

The second chemical method of applying the antimony coat which the Egyptians may have used was as follows: One liter of vinegar, 200 grams of sodium chloride and 5 grams of antimony oxide. The copper articles held in contact with iron, when immersed in the bath, acquired a beautiful coating of antimony.

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