Aero engines, as the core power units of modern aircraft, operate in extremely demanding environments, particularly requiring stringent sealing performance in high-temperature and high-pressure components such as between blades and hubs. Traditional organic sealing materials are prone to degradation, cracking, or powdering under high-temperature conditions, leading to sealing failure and subsequently affecting engine efficiency and safety. Silicone-based sealants, due to their unique molecular structure and high-temperature resistance, have become a key material in addressing this technical challenge. This paper focuses on a high-performance silicone-based sealant, achieved through a high-temperature curing process, which exhibits exceptional temperature resistance (long-term endurance above 325°C) and can withstand extreme thermal shock and aging conditions, making it suitable for high-temperature sealing applications between engine blades and hubs.

Silicone-based sealants feature a siloxane bond (Si-O) as their backbone structure. This inorganic-organic hybrid material combines the heat resistance of inorganic materials with the flexibility of organic materials. The high-temperature curing process typically requires temperatures between 200°C and 300°C, forming a three-dimensional network structure through cross-linking reactions, thereby enhancing the material's mechanical strength and thermal stability. The cured sealant layer not only exhibits high bonding strength but also maintains elasticity across a wide temperature range, adapting to thermal expansion and vibrational stresses during engine operation. This product demonstrates long-term temperature resistance after curing, capable of operating in environments above 325°C for extended periods without significant performance degradation. This characteristic stems from the high bond energy of siloxane bonds (approximately 443 kJ/mol), making them more resistant to thermal degradation than carbon-based polymers.

In sealing applications between engine blades and hubs, the sealant must withstand extreme temperature cycles and oxidative environments. Tests show that the sealant layer, after aging at 400°C for 50 hours, exhibits no cracking or powdering. This is attributed to the addition of thermally stable fillers (such as silica or ceramic microparticles) in the material, which not only inhibit the thermal motion of polymer chains but also form a barrier to slow oxidative diffusion. Furthermore, the sealant layer maintains integrity after 50 cycles of thermal shock testing from room temperature to 400°C, with no cracking or powdering. The thermal shock test simulates rapid temperature changes during engine start-up and shutdown, and its successful passage demonstrates the sealant's excellent thermal expansion coefficient matching and anti-fatigue performance, avoiding failures caused by thermal stress concentration.

From an application perspective, the construction process of this silicone-based sealant requires strict control of the curing curve and coating thickness to ensure the formation of a uniform layer on complex geometric surfaces (such as blade tenon grooves). Its moderate flowability allows it to fill micron-level gaps while forming strong chemical bonds with metal substrates (such as nickel-based alloys or titanium alloys). In actual engine tests, this sealant significantly improves sealing efficiency, reduces high-temperature gas leakage, and thereby optimizes the engine's thermal efficiency and thrust output. Additionally, its long-life characteristics reduce maintenance frequency and costs, meeting the dual requirements of reliability and economy in the aviation industry.

In summary, this silicone-based high-temperature sealant achieves breakthrough temperature resistance and durability through a high-temperature curing process and optimized formulation design, meeting the demands of high-temperature sealing in aero engines. In the future, with advancements in materials science, such sealants are expected to expand into other high-temperature industrial fields, such as gas turbines and aerospace propulsion systems, providing key technical support for high-end equipment manufacturing. Research continues to focus on the integration of nano-fillers and the optimization of interface engineering to enhance their application potential in ultra-high-temperature (above 500°C) environments.