The aeronautical nickel superalloy will increase its creep strength after adding thorium. Thorium alloys generally contain 3% to 6% thorium. The second-generation alloy has a thorium content of 3% and was used in F-16 and F-15 engines. The third-generation single crystal alloy contains up to 6% rhenium and is used in F-22 and F-35 engines. Rhenium alloys are also widely used in industrial gas turbine engines, such as GE 7FA.
Tungsten, a very high hardness, is a steel gray to white transition metal. Its physical characteristics are very strong, especially its melting point is very high. It is the champion of non-alloy metals. However, tungsten is mainly used as tungsten filament light bulbs, X-ray tubes and high-temperature alloys. In addition, tungsten is too heavy (high density), the hardness is too high, and the toughness is insufficient. Moreover, tungsten also reacts with oxygen or nitrogen in the air under high temperature environment, becoming more brittle. These shortcomings have caused tungsten to be rarely used in aeronautical applications.
Rhenium is a chemical element with the symbol Re, and its atom number is 75. It is a silver-white heavy metal that belongs to the sixth period transition metal in the periodic table. Rhenium is also one of the rarest elements in the earth's crust, with an average content estimate of one billionth. PRhenium was discovered by scientists in 1925, and it was also the last stable element found. At the same time, it is also one of the elements with the highest melting point and boiling point. The melting point of Rhenium is as high as 3182 degrees Celsius. Correspondingly, the melting point of nickel is only 1455 degrees Celsius. Rhenium is a silver-white heavy metal, which belongs to the sixth period transition metal in the periodic table.
The biggest application is in the field of aerospace.
Rhenium is one of the rarest elements in the world, with an average content of only one billionth. It is one of the elements with the highest melting point and boiling point. Nickel-rhenium superalloys are widely used in the manufacture of jet engine combustion chambers, turbine blades, and Exhaust nozzle.
Rhenium is more difficult to obtain than diamond and is expensive, with an average price of $ 4,575 per kilogram in 2011. About 7% of global plutonium is used in the production of aero-engines, which is of great military significance. Second, thorium is also an important catalyst in the chemical industry. It is mainly used in platinum-rhenium catalysts and can be used to produce lead-free, high-octane gasoline.