The core reason why fluorosilicone oil is irreplaceable in the aviation industry lies in its unique molecular structure, which provides extreme environmental adaptability. This allows it to maintain stable physical and chemical properties under harsh conditions such as high temperature, low temperature, vacuum, and strong corrosion, which is unmatched by traditional silicone oils and ordinary lubricants.

I. Stable Performance in Extreme Temperature Environments
Wide operating temperature range: Fluorosilicone oil can operate stably in a temperature range of -60℃ to 200℃, or even wider, with some modified products having a temperature range of -70℃ to 250℃. This is crucial for aircraft operating in alternating conditions of high-altitude low temperatures (such as -55℃) and high-temperature engine areas (above 150℃).
Excellent low-temperature fluidity: It maintains good fluidity even at extremely low temperatures of -55℃, ensuring the normal operation of aircraft fuel systems and hydraulic systems in cold regions or during high-altitude flight. Ordinary silicone oils tend to solidify at low temperatures, while the fluorocarbon side chains of fluorosilicone oil effectively lower the pour point.
Outstanding high-temperature stability: At a high temperature of 200℃, the thermal oxidative stability of fluorosilicone oil is significantly better than traditional ester-based aviation lubricants. Research data shows that the viscosity change of fluorosilicone oil after 50 hours at 250℃ is only 18.8%, while the viscosity change of ordinary ester-based oil after 50 hours at 220℃ is as high as 48.4%.

II. Excellent Chemical Stability and Corrosion Resistance
Oil and solvent resistance: The molecular structure of fluorosilicone oil contains trifluoropropyl functional groups, giving it stable resistance to hydrocarbon solvents and strong oxidizers. In the aviation field, this means it can resist the erosion of aviation kerosene and methanol-containing gasoline, while ordinary silicone oils are easily dissolved.
Chemical corrosion resistance: In a methanol-containing gasoline mixture system, fluorosilicone rubber showed very little change in hardness, tensile strength, and volume after a 500-hour immersion test. This is crucial for critical components that come into contact with fuel, such as aircraft fuel tank pressure regulating lines and vent valves. Excellent Antioxidant Performance: The strong electronegativity of fluorine atoms endows fluorosilicone oil with excellent antioxidant properties and chemical inertness, effectively resisting free radical-induced chain oxidation reactions and maintaining long-term stability in high-altitude, high-oxygen environments.


III. Functional Advantages in Special Environments
Vacuum Environment Adaptability: Under a vacuum of 10⁻⁵ Pa, fluorosilicone oil exhibits minimal volatilization, preventing contamination of optical lenses and electronic components. Its evaporation loss rate at 99℃ is only 0.3%, significantly lower than the 0.8% of imported Dow Corning DC 111, and it has passed NASA vacuum volatilization tests.
Low Surface Tension Characteristics: The surface tension of fluorosilicone oil is as low as 20-25 mN/m, approximately 30% lower than traditional silicone oil, allowing it to form a more durable lubricating film on metal surfaces and significantly reduce the steel-steel boundary friction coefficient.
Excellent Electrical Insulation Performance: With a volume resistivity exceeding 1 × 10¹⁵ Ω·cm, it is suitable for high-frequency communication substrates and provides reliable insulation protection in avionics equipment, preventing electromagnetic interference.

IV. Irreplaceable Role in Key Application Scenarios
Aircraft Engine Sealing: As a sealing material for critical components of aircraft engines, the high-temperature resistance, airtight degradation resistance, and electrical insulation properties of fluorosilicone oil make it indispensable for potting, bonding, and sealing electrical components in fuel systems.
Fuel Tank System Applications: Used in diaphragms for valves in aircraft fuel tank pressure regulating pipelines and diaphragms for fuel tank vent valves, it can be used long-term in kerosene vapor at -55℃ to 200℃ and RP kerosene at 150℃.
Precision Component Lubrication: On precision transmission components such as satellite solar panel drive bearings, fluorosilicone oil exhibits a starting torque of only 0.07 N·m at -60℃ and 3000 r/min, 30% lower than the average level of aviation-grade imported brands, making it suitable for precision transmission components.
Corrosion-Resistant Antifoaming Agent: In the aerospace manufacturing process, fluorosilicone oil acts as a corrosion-resistant and solvent-resistant antifoaming agent, effectively solving foaming problems during high-temperature processing and ensuring process quality. V. Future Development and Technological Breakthroughs
Current research is focusing on optimizing antioxidants to break through the long-term service temperature limit of 250°C.  If progress can be made in achieving stability at 300°C, it will further expand its application prospects in the hot end components of ultra-high-speed aircraft (such as engine bearing lubrication and high-temperature coatings). At the same time, the green manufacturing process achieves a comprehensive utilization rate of 98% for by-products, and the unit energy consumption is reduced to 0.85 kgce/kg, making fluorosilicone oil more competitive in the increasingly stringent environmental requirements of the aviation industry.
Thanks to these unique properties, fluorosilicone oil has become an indispensable special material in the aerospace field. Its reliable performance in extreme environments ensures flight safety, reduces maintenance costs, and extends equipment life, which is its core value that other materials cannot easily replace.