Rhenium is an extremely rare and highly superior refractory metal (with a melting point only slightly lower than that of tungsten). Its core advantages lie in its extremely high melting point and boiling point, combined with excellent high-temperature mechanical properties, outstanding catalytic activity, and the "reineffect" of alloying enhancement. It is a strategic material in high-end fields such as aerospace, petrochemicals, and electronics.
Room temperature and high-temperature strength: The tensile strength of pure rhenium at room temperature is approximately 1000-1200 MPa, with an elongation rate of 15%-20%; the strength retention rate at 1000°C exceeds 80%, and at 1500°C, it still remains at 400-500 MPa. The anti-warping performance is outstanding, making it suitable for long-term high-temperature load conditions. "Rhenium effect" (core characteristic): A small amount of rhenium (such as 3% added in nickel-based single crystal alloys) can simultaneously enhance the strength and toughness of the alloy, breaking the "strength - toughness contradiction" rule, inhibiting high-temperature warping and crack propagation, and significantly extending the component lifespan. Processing performance: Good cold processing performance, capable of being rolled into foils or drawn into fine wires; hot processing requires precise temperature control (to avoid oxidation), and powder metallurgy and electron beam melting are the mainstream preparation processes.
Antioxidation and corrosion resistance: Forms a dense oxide film on the surface at room temperature, resistant to dilute acids and alkalis; Re in block form is stable below 1273K, and oxidizes to form volatile Re₂O₇ above 1273K; insoluble in hydrochloric acid and hydrofluoric acid, soluble in nitric acid and hot concentrated sulfuric acid. It has a rich range of chemical active valence (-1 to +7, common +4, +7), and the powdered form of Re is more prone to reaction, capable of forming compounds with sulfur, halogens, etc., providing a basis for catalysis and extraction. It does not react directly with hydrogen and nitrogen, but can absorb hydrogen; at high temperatures, it forms carbon-reduced Re with carbon, improving the wear resistance and high-temperature stability of the alloy.
The rare crustal abundance is only 10⁻⁷%, with an annual global production of approximately 50-60 tons. The cost is extremely high, and it is mostly used in "trace addition" form.
The risk of high-temperature oxidation above 1273K easily leads to the formation of volatile Re₂O₇, and it requires antioxidant coatings such as silicides and MCrAlY.
The processing cost and preparation process are complex, and strict control of impurities and microstructure is necessary to meet the requirements of high-end manufacturing. The core value of rhenium lies in "performance stability in extreme environments" and "multiplier effect of alloy strengthening", making it a key material for driving technological breakthroughs in aerospace, energy, and chemical industries. If it needs to be used for long-term service at temperatures above 1200℃ and with strict requirements for strength and toughness, rhenium-based materials or rhenium-containing alloys are preferred options.
High-temperature temperature measurement and thermocouples in the electronic field: The tungsten-rhenium thermocouple (W-Re series) is the main instrument for measuring the range from 0°C to 2500°C. It has good stability and high thermoelectric potential. This is a classic application of the "rhenium effect", which solves the brittleness problem of pure tungsten. Heating elements, filaments, X-ray targets: Utilizing its high melting point, low vapor pressure, and good electron emission performance. Petrochemical catalyst platinum-rhenium (Pt-Re) reforming catalyst: Used for producing high-octane unleaded gasoline. Rhenium can greatly improve the stability, selectivity, and anti-poisoning ability of the platinum catalyst, extending the catalyst's service life by several times.
Compared with niobium C103, rhenium has a higher temperature: the effective working temperature upper limit of rhenium (especially in vacuum/inert environments) is higher than that of C103. It has an extremely high density: the density of rhenium is 2.4 times that of C103, and it is not suitable for the main structure of spacecraft that requires extremely sensitive weight. Complementary applications: C103 is used in large, lightweight rocket nozzles; rhenium is used in small, extremely reliable attitude engine combustion chambers or as an alloy element.
