NBR vs. FKM – What is the difference?

This article explains the main differences between NBR and FKM, two of the most commonly used sealing materials. Both materials are a good choice for general industrial use, they offer excellent resistance to compression set and have a wide range of applications and interesting property profiles

However, these two gaskets have different properties, application types and characteristics. If you are considering the use of NBR and FKM, here are some points to consider:

NBR Nitrile rubber gasket material

Temperature: NBR is effective in a temperature range of -30°C to 100°C.
General suitability: Used for general applications requiring resistance to aliphatic hydrocarbons, petroleum, water and hydraulic fluids.
Environmental properties: NBR, unlike FKM, is not resistant to the effects of weathering and ozone. These seals are resistant to most oils and lubricants, especially petroleum-based lubricants, and have other advantages such as excellent abrasion and tear resistance, making them suitable for heavy industrial applications.
Applications: A cost-effective product that works well with restricted temperatures and chemical resistance.

FKM gasket material

Temperature: FKM gaskets can withstand temperatures between -20°C and 210°C. FKM gaskets tend to fail in dynamic applications below -15°C as they become inflexible and hard.
General suitability: FKM is best suited for a wide variety of sealing applications requiring high temperature and chemical resistance. In applications involving contact with petroleum, acids, silicone fluids and gases, halogenated hydrocarbons (trichloroethylene and carbon tetrachloride), aromatic hydrocarbons, seals and O-rings made of FKM are generally used.
Environmental properties: O-rings and seals made of FKM have a wide range of chemical resistance (to mineral acids, fuels and oils). In addition, this material is highly resistant to oxidation, UV radiation, fungi, weathering, ozone and mold. Thus, FKM is far superior to NBR in these respects. They are also resistant to most oils and lubricants, especially petroleum-based lubricants.
Applications: FKM is proving its worth in a variety of automotive, chemical and household appliance applications.
Cost: As an approximate guide, FKM is ten to fifteen times more expensive than NBR.

The properties of FKM are significantly different from those of NBR. It is essential to consider the advantages and disadvantages of both materials, especially in the context of the particular application.


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