|Molecular Weight||186.207 g/mol|
|APS||<40 µm (can be customized)|
|Melting Point||3186 °C|
|Boiling Point||5630 °C|
The earliest structural applications of CYD rhenium was in the fabrication of tubing for thennocouple sheaths. The capability to measure temperatures up to 2,6OO”C in fission reactors has been demonstrated. With the addition of an iridium coating, temperatures of 2,4OO”C can be measured in an oxidizing environment In 1981, Ultramet begana program With NASA’s Jet Propulsion Laboratory to develop the technology to fabricate rhenium thrust chambers for liquid fluorine/ hydrazine chemical rockets.9 This program culminated in the fabrication of a rhenium chamber 610 mm long with a 250 mm diameter exhaust cone. The work demon· strated that with the use of fuel-film cooling to keep the throat temperature below 1,.53(r’C, a minimum life of several hours could be expected. The high·temperature strength, resistance to hot hydrogen and minimal hydrogen permeability of rhenium were utilized in fabricating a solar rocket for the Air Force. 10 This unit consists of a heat exchanger made of rhenium tubing that translers the thennal energy 01 solar radiation to hydrogen, which expands and is exhausted through a rhenium nozzle, pro:lucing thrust. Maximum test temperatures reached 2,5OO”‘C. Hydrogen containment work using rhenium is currently being funded under the national aerospace plane program. Rhenium is a chemical element with the symbol Re and atomic number 75. It is a transition metal of the third row, silver-gray, heavy in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the earth’s crust. Rhenium has the third-highest melting point and the second-highest boiling point of any element in 5903 K. Rhenium chemically recalls manganese and technetium and is obtained mainly as a byproduct of the extraction and refining of copper and molybdenum ores. Rhenium shows in its compounds a great variety of oxidation states ranging from -1 to +7.