What is the Difference Between FKM and FFKM?

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FKM and FFKM are both synthetic rubbers known for their chemical resistance and heat resistance. The main differences between them are:

  1. Fluorine Content: FKM, also known as fluoroelastomer, is a fluorinated carbon-based synthetic rubber, while FFKM, or perfluoroelastomer, contains higher amounts of fluorine than standard FKM. This higher fluorine content in FFKM results in improved chemical resistance and higher temperature ratings.
  2. Temperature Ratings: FKM is known for its impressive heat resistance, allowing seals to withstand temperatures greater than 200°C. On the other hand, FFKM can withstand peak service temperatures of up to 330°C.
  3. Chemical Resistance: Both FKM and FFKM exhibit excellent resistance to heat, chemicals, and other fluids, including several fuels. However, FFKM offers nearly universal chemical compatibility, making it more resistant to a broader range of chemicals.
  4. Applications: FKM materials are commonly used to manufacture O-rings, seals, and gaskets for critical applications in automotive, aerospace, energy, semiconductor, and industrial operations. FFKM, due to its higher temperature and chemical resistance, is often selected for more demanding applications where seal failure could have severe consequences.

In summary, while both FKM and FFKM are known for their chemical and heat resistance, FFKM offers improved chemical resistance and higher temperature ratings due to its higher fluorine content. This makes FFKM more suitable for applications that require a broader range of chemical compatibility and higher temperature resistance.

Comparative Table: FKM vs FFKM

FKM and FFKM are both types of elastomer materials containing fluorocarbon structures, but they have slightly different chemical and physical properties. Here is a comparison table highlighting the differences between FKM and FFKM:

Property FKM (Fluoroelastomer) FFKM (Perfluoroelastomer)
Versatility Less versatile than FFKM More versatile than FKM
Chemical Resistance Resistant to many chemicals, solvents, oils, and fuels Excellent chemical resistance, including resistance to ketones, esters, ethers, and most acids
Temperature Resistance Operates efficiently at high temperatures, but with lower temperature ratings compared to FFKM Can withstand a greater range of operating temperatures, offering peak service temperatures of up to 330°C
Resilience Slight advantage in short-term resilience Slight advantage in permeation resilience
Compression Set Resistance Slight advantage in compression set resistance Slight advantage in compression set resistance
Electrical Current Resistance Slight advantage in electrical current resistance Slight advantage in electrical current resistance
Wear Resistance Slight advantage in wear resistance Lower wear resistance compared to FKM
Weathering Resistance Specific resistance to weathering and sunlight Excellent resistance to weathering, sunlight, and a broad spectrum of chemicals

Both FKM and FFKM are used in various applications, including automotive, chemical processing, oil and gas production, heavy-duty machinery, and aerospace. However, FKM is more widely used due to its lower cost, while FFKM is primarily used in aerospace and automotive industries.