Fluoroelastomer (FKM/Viton)

FKM (Fluoroelastomer/Viton): Premium High-Performance Elastomer

Fluoroelastomer (FKM), commonly known by the trade name Viton®, is a premium synthetic rubber engineered for extreme chemical resistance, high-temperature performance, and long-term durability in the most demanding industrial environments. Specified across aerospace, automotive, chemical processing, and oil & gas applications, FKM delivers unmatched sealing reliability where standard elastomers cannot survive.

Key Properties of FKM Rubber

• Exceptional Chemical Resistance: Superior resistance to acids, fuels, oils, solvents, and aggressive chemicals
• High Temperature Performance: Continuous operation from -20°F to 400°F (-29°C to 204°C), with specialty grades to 500°F
• Fuel & Oil Resistance: Outstanding resistance to petroleum fuels, synthetic oils, and aromatic hydrocarbons
• Low Permeability: Minimal gas and fluid permeation—ideal for critical sealing applications
• Oxidation & Aging Resistance: Excellent long-term stability in high-temperature oxidative environments
• Compression Set Resistance: Superior resistance to permanent deformation at elevated temperatures
• Flame Resistance: Self-extinguishing with excellent flame and smoke resistance

Common Applications & Uses

• Aerospace: Fuel system seals, O-rings, gaskets for jet fuel and hydraulic systems
• Automotive: Engine seals, fuel injector O-rings, transmission seals, turbocharger gaskets
• Chemical Processing: Pump seals, valve seats, gaskets for aggressive chemical environments
• Oil & Gas: Downhole seals, wellhead equipment, high-temperature/high-pressure applications
• Semiconductor: Plasma-resistant seals, vacuum chamber gaskets, chemical delivery systems
• Industrial: High-temperature hoses, expansion joints, chemical-resistant coatings
• Pharmaceutical: Sterile seals, autoclave gaskets, chemical-resistant components

Advantages of FKM

• Industry-leading chemical resistance—compatible with acids, fuels, oils, and aggressive solvents
• Highest continuous temperature rating among common elastomers (up to 400°F standard, 500°F specialty)
• Exceptional resistance to aromatic and chlorinated hydrocarbons (benzene, toluene, TCE)
• Superior compression set resistance at elevated temperatures
• Extremely low permeability to gases and fluids for critical sealing
• Excellent oxidation and weathering resistance for long service life
• Flame-resistant and self-extinguishing properties
• Multiple grades available for specific chemical and temperature requirements

Limitations & Disadvantages

• High Cost: Significantly more expensive than NBR, neoprene, EPDM, and other standard elastomers
• Poor Low-Temperature Flexibility: Limited flexibility below -20°F; specialty low-temp grades required for cold environments
• Steam & Hot Water Incompatibility: Not suitable for steam or hot water applications—EPDM is superior
• Polar Solvent Sensitivity: Poor resistance to ketones, esters, and some amines
• Processing Complexity: Requires specialized compounding and curing processes
• Adhesion Challenges: Difficult to bond without specialized primers or surface treatments

FKM vs. Other Rubber Materials

FKM vs. NBR (Nitrile): FKM offers superior chemical resistance, higher temperature capability (400°F vs. 250°F), and better aromatic hydrocarbon resistance. NBR is more cost-effective with better low-temperature flexibility for standard petroleum applications. Use FKM for extreme conditions; NBR for cost-sensitive oil/fuel contact.

FKM vs. EPDM: FKM excels in fuel, oil, and chemical resistance with high-temperature performance, while EPDM is superior for weather, steam, and hot water applications. FKM is the choice for chemical/fuel systems; EPDM for outdoor sealing and water contact.

FKM vs. Silicone: Both offer high-temperature performance, but FKM provides superior fuel and oil resistance while silicone offers better low-temperature flexibility (-65°F) and broader temperature range. FKM is preferred for fuel/chemical contact; silicone for extreme temperature cycling without chemical exposure.

FKM vs. Neoprene: FKM significantly outperforms neoprene in chemical resistance, temperature capability, and compression set resistance. Neoprene is more economical for moderate-exposure applications. FKM is specified for severe chemical and high-temperature environments.

FKM vs. FFKM (Perfluoroelastomer): FFKM offers even broader chemical resistance and higher temperature capability (up to 600°F), but at significantly higher cost. FKM is the cost-effective choice for most demanding applications; FFKM for the most extreme chemical and thermal conditions.

FKM Grades & Types

• Type A (Dipolymer): Standard grade with excellent fuel and oil resistance—most common general-purpose FKM
• Type B (Terpolymer): Enhanced chemical resistance, particularly to acids and steam—broader compatibility
• Type F (Tetrapolymer): Superior low-temperature flexibility with maintained chemical resistance
• GLT/GFLT: Specialty low-temperature grades for cold-environment applications
• Extreme grades: High-temperature formulations for continuous service to 500°F

Technical Specifications

• Hardness Range: 55–90 Shore A (customizable by formulation)
• Specific Gravity: 1.80–1.95
• Tensile Strength: 1,000–2,500 psi (varies by grade)
• Elongation at Break: 150–300% (varies by formulation)
• Compression Set: Excellent at elevated temperatures (typically <25% at 200°C/392°F for 70 hours)
• Temperature Range: -20°F to 400°F continuous (-29°C to 204°C), specialty grades to 500°F

Why Choose FKM from Rubber Mexico?

Our FKM compounds are formulated for maximum chemical resistance, thermal stability, and sealing performance across aerospace, automotive, chemical processing, and oil & gas applications. With in-house molding, precision machining, and custom compounding capabilities, we deliver mission-critical FKM components engineered to your exact specifications and operating conditions.

Need a custom FKM solution? Contact us for material selection guidance, grade optimization, compound development, prototyping, and production support for your most demanding sealing challenges.