Silver coatings have a very high reflection ability. To avoid their darkening from the hydrogen sulphide in the air, a thin layer of heat-resistant colorless lacquer is applied to the coatings. Silver plating is mainly used in jewelery, optics, electronics and electrical engineering. Depending on their application the thickness of the layer may vary from 2 to 24 μm. It can be done in several ways: chemical, electrochemical, contact, etc. The most common way of silver plating is the electrochemical deposition using cyanide and non-cyanide electrolytes. The cyanide electrolytes produce light, fine crystalline, dense and plastic coatings upon silver-plating. Usually silver coatings are applied with copper or nickel intermediate layer. In order to improve the de-oxidation of the aluminum surface new chemical treatment in acid – alkaline solution was applied. Our previous research shows that the presence of diamond nanoparticles in the electrolyte increase the metal deposition. Samples were prepared from electrolyte containing 10 g/l diamond nanoparticles. Their properties were compared to the properties of reference samples. The diamonds were obtained by detonation synthesis. The aim of this study is to obtain electrochemically deposited silver layer with high density, adhesion and electric conductivity on aluminum alloys substrate. The coatingwas directly plated without intermediate layer. Non-cyanide electrolyte composition and electrochemical parameters were determined in order to produce Ag coatings on Al alloy substrate without intermediate layer. The coating is with good adhesion, density and thickness of 14-23 μm.

The subject of this article is the fragmentary silver plate of a gilded silver sheet braid ornament decorated with palmette motifs, which was deposited in the storage of the Gorgippia Archaeological Museum (Krasnodar Krai, Russia) in 2015, together with several other finds. The finds had been discovered at a site named Andreyevskaya Shhel, located a few kilometres south-east of the town, at the north-western hill area of the Caucasus. Among the artefacts deposited in the storage in 2015, there were other finds related to the 9–10th centuries (e.g. silver plate of a sabretache, gilded bronze belt mounts, bronze strap end, sabre, bow case or sabretache mount, fingering, etc). The braid ornament, with many analogies in the Carpathian Basin, could have reached the North Caucasian region by means of long-distance trade. This hypothesis is sustained by the considerable dirham-finds in the Carpathian Basin, which indicate the integration of this region – and of early Hungarian commerce as a whole – into the Eastern, Muslim trade network.