Aerospace-specific silica sol

#Application ·2025-08-21 17:07:44

• Characteristics
  • Outstanding high-temperature resistance: Pure silica has a melting point of 1700℃. After modification and combination with other materials, it can withstand an instantaneous high temperature of 3000℃, effectively resisting extreme high-temperature environments such as rocket tail flames.
  • Reasonable particle size distribution: The particle size is usually between 5 and 100 nanometers. A smaller particle size is conducive to uniform dispersion in the material, thereby better exerting its reinforcing and heat insulation functions.
  • Low density and high strength: The density can be as low as 1.4g/cm³, only 50% of that of aluminum alloy, but the strength can be increased by 3 to 5 times, which is conducive to the lightweighting of aerospace vehicles while ensuring the strength and stability of the structure.
  • Excellent chemical stability: In extreme environments such as high temperatures and high radiation, silica sol can maintain structural stability, is not prone to decomposition or failure, and has good chemical inertness.
  • High surface activity: The surface of silica sol particles is covered with hydroxyl groups, which can form strong hydrogen bonds and chemical bonds with other hydroxylated surfaces, facilitating surface modification, such as grafted silane coupling agents and carbon nanotubes, thereby endowing the material with hydrophobic, conductive, self-healing and other properties.
  • Good radiation resistance: Silicon dioxide has a high absorption rate for gamma rays, proton flow, etc., which is about 40% higher than that of traditional materials. It can be used to prepare anti-radiation coatings to protect the electronic equipment of aerospace vehicles from radiation damage.
• Applications in the aerospace field
  • Thermal protection system: It can be used to prepare silica sol reinforced ceramic matrix composites. For instance, NASA used silica sol to bond SiC fibers in the Orion spacecraft, reducing the ablation rate by 60%. In addition, silica sol-derived aerogel has also been applied in insulation layers. For instance, the thermal conductivity of the aerogel used in the Tianwen-1 Mars probe is as low as 0.013W/(m · K).
  • Lightweight structural materials: Used for modifying carbon fiber composite materials. For instance, after the fuel tank of the European Airbus Ariane 6 rocket was modified with silica sol, its weight was reduced by 30% and its load-bearing capacity was increased by 25%. The silica sol-titanium alloy honeycomb sandwich structure can also be used for the starship shell, with a compressive strength of up to 800MPa.
  • Anti-radiation coating: For instance, Japan's JAXA applied a silica sol/graphene composite coating to the electronic cabin of the Hayabusa2 probe, enhancing its proton radiation resistance by four times. The solar panels on the International Space Station use a silica sol encapsulation layer, which can reduce the annual loss rate of efficiency attenuation caused by cosmic rays from 3% to 0.7%.
  • Propulsion system: It can be used as a high-temperature adhesive for rocket engine nozzles, such as the silica sol bonded hafnium carbide coating of ULA Company's Vulcan rocket in the United States, which can increase the temperature resistance to 2800℃ and extend the service life by two times. Meanwhile, the silica sol micro-crack repair technology can support more than 10 cycles of use for SpaceX Raptor engines.
• Application advantages
  • High-precision casting: Silica sol investment technology can achieve high-precision casting, better reproducing complex shapes and fine structures, and meeting the high-precision requirements of aerospace components.
  • Excellent surface quality: Using silica sol as the mold material, the surface of the castings is smooth and free of obvious casting defects, which can reduce the demand for subsequent processing, save costs and time.
  • Low residual stress: The design and material properties of silica sol investment molds result in relatively small residual stress generated during the cooling process of castings, reducing the risk of deformation and cracking caused by stress, and enhancing the reliability and service life of castings.