Rhenium was discovered in 1925 by W. Noddack, O. Berg and Ida Tacke in Berlin, Germany. Rhenium was named after "Rhenus", the Latin name for the Rhine. It is a rare element (abundance 4 x 10⁻⁴ ppm in the earth's crust) and does not occur in quantity in any ore. It is found in ores which contain molybdenum from which it can be readily recovered. The metal is obtained by hydrogen reduction of the potassium perrhenate salt, obtained by precipitation of the perrhenate ion (ReO₄)⁻- from an oxidised solution. Rhenium is a silvery coloured metal which resists corrosion and oxidation but slowly tarnishes in moist air. It is soluble in nitric and sulphuric acids. Applications for the metal include its use as an alloying element with tungsten, the resulting alloy having a very high electrical resistance making it suitable for electrical filaments. Rhenium has a very high melting point and is used in high temperature thermocouples, electrical contacts and thermistors.
Small particles with an approximately defined size range. Those materials described as alloy precursors are not true alloys - they are made by sintering a blend of powders of the component metals to achieve alloying by diffusion. The resultant cake is ground and sieved to the required particle size range. Unless otherwise stated, the particle sizes shown are for guidance only. We do not guarantee either any particular size distribution between the quoted minimum and maximum sizes, or a specific particle shape.