Zolotnik Zolotnik A zolotnik (in Russian: золотни́к; abbr.: zol.) was a small Russian unit of weight, equal to 0.1505 avoirdupois ounces, or 4.2658 grams (about 65.83 grains). Used from the 10th to 20th centuries, its name is derived from the Russian word "zoloto", meaning gold. As a unit, the zolotnik was the standard for silver manufacture, much as the troy ounce is currently used for gold and other precious metals. This unit was originally based on a coin of the same name. The zolotnik circulated in the Kievan Rus until the 11th century; it was equal in weight to the Byzantine
Refractory metals to other refractory metals, where it adds ductility and tensile strength. Rhenium alloys are being used in electronic components, gyroscopes and nuclear reactors. Rhenium finds its most important use as a catalyst. It is used as a catalyst in reactions such as alkylation, dealkylation, hydrogenation and oxidation. However its rarity makes it the most expensive of the refractory metals. Refractory metals and alloys attract the attention of investigators because of their remarkable properties and promising practical usefulness. Physical properties of refractory metals, such as molybdenum, tantalum and tungsten, their strength, and high-temperature stability make them suitable material for hot metalworking