In the aerospace field, O-rings, as a key sealing component, are widely used in a variety of equipment and systems such as engines, hydraulic systems, fuel systems, air systems, landing gear, and space capsules. Due to the particularity of the aerospace environment, there are extremely strict requirements for the selection of O-ring materials. The materials must not only have excellent sealing and durability, but also be able to adapt to extremes such as high and low temperatures, vacuum, high pressure, and corrosive chemicals. environment. The following will be an in-depth discussion of several commonly used O-ring materials and their application characteristics and advantages in aerospace.
1. Fluorine rubber (Viton/FKM)
Fluoroelastomer (FKM) is one of the most commonly used sealing materials in the aerospace industry and is known for its excellent resistance to high temperatures and chemical corrosion. The working temperature range of fluorine rubber is wide, usually between -20°C and 200°C, and some special varieties can even reach 250°C. Therefore, it is ideal for use in high-temperature environments such as aircraft engines and turbines.
Another notable feature of fluororubber is its resistance to various chemicals such as aviation fuel, lubricants, and hydraulic oils. This material can effectively resist corrosion from fuel, lubricants and many synthetic fluids, thereby maintaining its sealing effect. In addition, fluorine rubber has good anti-aging properties, is not easily affected by thermal oxidation, and will not embrittle or deform during long-term use.
Applications: Fluorine rubber is widely used in the fuel system and hydraulic system of aircraft engines, and is also commonly used in seals in aircraft cabins, such as fuel tank seals and oil system seals.
2. Polytetrafluoroethylene (PTFE)
Polytetrafluoroethylene (PTFE) has extremely high temperature resistance, with an operating temperature range of -200°C to 260°C, making it an ideal material that can handle extreme temperature changes. In addition, PTFE material has very high chemical stability and is resistant to corrosion to almost all chemicals, making it suitable for corrosive media sealing environments.
Another advantage of PTFE is its low friction, which makes it perform well in high-frequency vibration environments, effectively reducing wear caused by friction and extending the service life of seals. However, PTFE has poor elasticity and requires special design to ensure sealing performance.
Applications: PTFE is commonly used in aerospace components with high temperatures or severe chemical corrosion, such as seals in aviation fuel systems, liquid delivery pipelines and high-pressure systems.
3. Silicone
Silicone rubber remains flexible in temperatures ranging from -60°C to 200°C, making it ideal for high-altitude and low-temperature environments. Silicone rubber also has excellent resistance to oxidation and UV rays, so it can be used in seals exposed to the external environment. Its material is soft and can be effectively sealed. At the same time, it does not harden easily under low temperature conditions, avoiding the risk of embrittlement.
Although the mechanical strength and wear resistance of silicone rubber are not as good as other materials, silicone rubber is an ideal choice in some special sealing environments, such as aircraft and spacecraft operating at high altitudes, especially in extreme cold environments. protrude.
Applications: Silicone rubber is mainly used in low-temperature sealing applications in aerospace, such as spacecraft seals, outer space capsules, and low-temperature seals in aircraft cabins.
4. Hydrogenated nitrile rubber (HNBR)
Hydrogenated nitrile butadiene rubber (HNBR) can maintain stable sealing performance in both low and high temperature environments, and the operating temperature range is usually between -40°C and 150°C. HNBR material has good resistance to aviation hydraulic oil and fuel, and also has good ozone resistance, aging resistance and wear resistance, so it can maintain a good sealing effect in ozone exposure and radiation environments.
HNBR is relatively hard but has good tear resistance, so HNBR is widely used to seal various components in aviation hydraulic systems and fuel systems in environments that require oil resistance and corrosion resistance.
Applications: HNBR is often used in aircraft hydraulic systems, fuel pipelines and other components that need to seal fuel and hydraulic oil.
5. Ethylene propylene rubber (EPDM)
The operating temperature range of ethylene propylene rubber (EPDM) is between -50°C and 150°C, making it suitable for use in extremely cold high-altitude environments. Ethylene-propylene rubber has good resistance to ozone, ultraviolet rays and oxidation, and is suitable for use in seals that are externally exposed to the atmospheric environment. It also has good resistance to water and steam and can be used in humid environments without affecting its sealing properties.
EPDM materials are not suitable for sealing oil-containing media, but they perform well in waterproof sealing and thermal insulation applications, and are particularly suitable for use as weather-resistant seals.
Applications: EPDM is widely used in aircraft airtight doors, window seals and other waterproof and anti-aging sealing parts.
6. Polyurethane (PU)
Polyurethane has excellent wear resistance and is suitable for sealing environments where high friction and vibration are present. Its operating temperature range is between -40°C and 80°C, and it has good flexibility and oil resistance. Polyurethane has excellent tear and fatigue resistance, making it suitable for use in parts that need to withstand long-term stress and impact.
Polyurethane also has good performance in oil resistance and is suitable for application environments that require oil resistance and wear resistance, especially in environments with serious oil pollution.
Applications: Polyurethane materials are often used in seals of landing gear systems and parts that require wear resistance, and are especially suitable for high-load sealing requirements.
7. Perfluoroether rubber (FFKM, Kalrez)
Perfluoroether rubber (FFKM) is known as the "king of sealing materials" and performs well in extreme temperature environments, able to withstand temperatures from -40°C to 327°C. FFKM material has extremely high corrosion resistance to most chemicals and can maintain good sealing performance even in extremely corrosive media. At the same time, it has strong resistance to compression deformation and is suitable for use in high-pressure and high-temperature environments.
FFKM materials are expensive and are usually only used in applications with extremely high sealing requirements, such as aerospace engines and high-temperature chemical reaction environments.
Applications: FFKM is used in high-temperature fuel systems in aircraft engines and high-demand sealing components in chemically corrosive environments.
Common characteristics of O-ring materials used in aerospace
• High reliability: In the aerospace field, O-rings must ensure stable sealing for a long time without allowing any leakage. Not only do materials have to adapt to different environments, they also need to have reliable sealing properties under long-term, high-pressure, high- and low-temperature conditions.
• Aging resistance: Since aerospace vehicles need to operate in harsh environments for a long time, the aging resistance of seals is crucial. Environments such as atmospheric oxidation, ozone and ultraviolet rays have a greater impact on materials. Therefore, many O-ring materials are designed with anti-oxidation, anti-ozone and anti-radiation properties in mind.
• Resistance to compression deformation: In high-pressure and high-temperature environments, O-ring materials are prone to permanent compression deformation, which will lead to a decrease in sealing effect. Therefore, the material needs to have good resistance to compression deformation and maintain elasticity and resilience under high pressure conditions.
• Flexibility to adapt to high and low temperatures: High and low temperatures in aerospace environments vary greatly. O-ring materials need to remain flexible at extremely low temperatures to avoid embrittlement or hardening, while not easily softening or chemically decomposing at high temperatures.
• Corrosion resistance: Aerospace vehicles need to face different chemical media, such as fuel, hydraulic oil, lubricating oil and coolant. O-ring materials need to have excellent corrosion resistance to ensure that the seal will not be corroded and fail when exposed to chemicals for a long time.
The demand for O-ring materials in the aerospace field is strict and diverse. Different materials have unique properties and are suitable for different working conditions. In practical applications, it is often necessary to select appropriate materials and designs to effectively ensure the safety and stability of equipment in extreme environments. Jinwoseal produces all the above-mentioned O-rings. From production to delivery, every step is strictly tested for quality to ensure that it can adapt to various harsh application environments. Every product is a commitment, and we look forward to every cooperation with you.
