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Sealing and thermal protection system of niobium-titanium alloy in extreme environments

The sealing performance of niobium-titanium alloy in high temperature, high pressure and ultra-low temperature environments is particularly outstanding. For example, the cold head of a quantum computer uses a niobium-titanium alloy pan-plug seal, which can still maintain nano-level sealing surface fit at ultra-low temperature of 4K and withstand the extreme temperature difference and pressure shock of the liquid helium environment. In the field of aviation engines, the pan-plug seal composited with metal bellows and PTFE can achieve zero leakage under the conditions of 200℃ and 50MPa, and has been used for precision sealing of fuel control systems. In addition, the C-type sealing ring uses Ti-6Al-4V alloy, combined with gold/molybdenum disulfide composite coating, which can withstand low temperature and high pressure shock of -253℃ in liquid oxygen/methane rocket engines, with a rebound rate of ≥95% and a leakage rate of less than 10^-9 Pa・m³/s. In the thermal protection system, the thermal barrier coating composed of niobium alloy and carbon nanotubes can work stably at 2300℃, and the Ta₄HfC₅ ceramic layer clad on the surface by laser forms a dense anti-oxidation barrier with a service life of more than 800 hours, which has been included in my country's hypersonic aircraft research and development plan. These applications fully demonstrate the reliability of niobium-titanium alloys under extreme working conditions and provide key support for the performance breakthrough of aviation equipment.