This is currently the most closely watched and fastest-growing application area for niobium alloys, which highly overlaps with and focuses on the application scenarios of tantalum alloys.
Hypersonic vehicle thermal protection system: Niobium alloys (especially niobium-hafnium alloys, such as C103 and Nb-1Zr) have become key materials for manufacturing hypersonic vehicle thermal protection systems (TPS) and engine components due to their excellent high-temperature strength, machinability and relatively low cost. They usually need to be coated with silicide antioxidant coatings (such as R512E) to work for a long time in the air at extremely high temperatures (above 1200-1400°C).
In a vacuum or near-vacuum environment, the high-temperature components of the engine nozzle cannot be cooled by air convection but instead dissipate heat into space through thermal radiation. Niobium alloy can still maintain sufficient strength at this temperature, and the anti-oxidation coating on its surface (usually silicides, such as R512E) protects it from being burned out.
Thrust chambers and nozzles of rocket engines: Niobium alloys have long been used to manufacture the extension sections of radiative cooling nozzles for liquid rocket engines due to their excellent thermal shock resistance and weldability. These components dissipate heat through radiation in a vacuum, allowing the high-temperature resistance of niobium alloy to be fully exerted.
C-103 (Nb-10Hf-1Ti) : This is the most classic and widely used niobium alloy in aerospace. It achieves the best balance among strength, processability and cost, and is widely used in rocket engine nozzles.
Nb-1Zr: It features excellent high-temperature creep strength and welding performance, and is commonly used in the nuclear industry. It also has applications in the aerospace field.
