Difference Between NBR and Viton (FKM): Which Rubber Seal Material Is Best for Your Application?

[2026-07-19] | By Xiamen Jinshun Sealing Technology Co., Ltd. Annie Xu

Difference Between NBR and Viton (FKM): A Complete Guide for Choosing the Right Rubber Seal

Selecting the correct sealing material is one of the most important decisions when designing hydraulic systems, pneumatic equipment, automotive components, pumps, valves, food machinery, or chemical processing equipment.

Among all elastomers used in industrial sealing, NBR (Nitrile Rubber) and Viton^® (FKM Fluoroelastomer) are the two most widely specified materials.

Although they may look similar, their performance differs significantly when exposed to high temperatures, aggressive chemicals, fuels, lubricants, ozone, UV exposure, and long-term compression.

Choosing the wrong material often leads to:

• Oil leakage
• Premature seal failure
• Increased maintenance costs
• Equipment downtime
• Expensive warranty claims

This guide compares NBR vs Viton from an engineering perspective to help OEM manufacturers, industrial buyers, maintenance engineers, and distributors select the right sealing solution.

NBR (Nitrile Butadiene Rubber), also called Buna-N, is a synthetic elastomer produced from butadiene and acrylonitrile (ACN).

Depending on the acrylonitrile content (typically 18–50%), manufacturers can balance oil resistance and low-temperature flexibility.

NBR has become the industry's standard sealing material because it offers:

• Excellent petroleum oil resistance
• High abrasion resistance
• Good mechanical strength
• Competitive cost
• Easy processing
• Wide availability

Today, millions of NBR O-rings, bonded seals, hydraulic seals, and oil seals are used in automotive, hydraulic, pneumatic, and industrial equipment worldwide.

Viton^® is the registered trademark originally introduced by DuPont (now Chemours) for FKM fluoroelastomer.

Unlike NBR, FKM contains approximately 66–70% fluorine, creating extremely strong carbon-fluorine bonds.

These molecular bonds provide exceptional resistance to:

• High temperatures
• Aggressive chemicals
• Synthetic lubricants
• Fuels
• Acids
• Oxidation
• Ozone
• UV exposure

Because of these properties, Viton seals are widely used in aerospace, petrochemical plants, semiconductor manufacturing, fuel systems, and high-performance automotive engines.

Chemical compatibility is often the deciding factor when selecting an elastomer.

Temperature is often the biggest factor affecting seal life.

NBR

Standard NBR performs well between:

-40°C to +120°C

Special formulations may reach 135°C, but long-term exposure shortens service life.

NBR also performs better than FKM in cold environments.

Viton (FKM)

Standard Viton operates between:

-20°C to +200°C

Premium grades can withstand:

• 230°C continuous
• 250°C intermittent

At elevated temperatures, FKM maintains elasticity much longer than NBR, reducing compression set and leakage.

For hydraulic cylinders, rotary shafts, and high-wear applications, NBR often provides better abrasion resistance.

Outdoor environments expose seals to:

• UV radiation
• Ozone
• Rain
• Heat
• Oxygen
• Viton dramatically outperforms NBR.

An NBR seal stored outdoors may crack after extended ozone exposure, while Viton maintains flexibility for years under similar conditions.

This makes FKM the preferred material for:

• Outdoor valves
• Petrochemical plants
• Solar equipment
• Marine equipment
• Aerospace

Price is another important consideration.

Although Viton costs more initially, its longer service life often reduces maintenance and replacement costs in demanding industrial applications.

NBR Applications

NBR remains the preferred choice for cost-effective sealing solutions.

Common industries include:

• Hydraulic cylinders
• Pneumatic systems
• Automotive oil seals
• Gearboxes
• Fuel systems
• Agricultural machinery
• Construction equipment
• Industrial pumps
• Standard O-rings
• Bonded sealing washers

Viton (FKM) Applications

FKM is selected when reliability under extreme conditions is essential.

Typical applications include:

• Aerospace
• Aircraft fuel systems
• Chemical processing
• Semiconductor manufacturing
• Pharmaceutical equipment
• Oil & gas
• High-temperature engines
• Turbochargers
• Fuel injection systems
• Vacuum equipment

The right material depends on your operating environment.

Choose NBR if your application requires:

• Low cost
• Good oil resistance
• Excellent wear resistance
• Temperatures below 120°C
• Standard hydraulic equipment

Choose Viton (FKM) if you need:

• High-temperature sealing
• Aggressive chemical resistance
• Long service life
• Outdoor weather resistance
• Fuel system compatibility
• Reduced maintenance

With over 22 years of manufacturing experience, Xiamen Jinshun Sealing Technology supplies custom rubber sealing solutions to OEM manufacturers and industrial customers worldwide.

Our Advantages

• ISO 9001:2015 & ISO 14001:2015 certified manufacturing
• OEM & ODM custom production
• NBR, FKM, EPDM, Silicone, HNBR and other elastomers
• ROHS, REACH and PAHS compliant materials
• FDA, NSF, WRAS, LFGB, ACS and UL approved material options
• Precision molding and strict quality inspection
• Fast prototype development
• Competitive factory pricing
• Global export experience

Our engineering team helps customers select the right sealing material based on temperature, pressure, media compatibility, compression set, hardness, and service life requirements.

Is Viton better than NBR?

Not always. Viton offers superior heat and chemical resistance, while NBR provides better wear resistance, better low-temperature flexibility, and significantly lower cost.

Is Viton more oil resistant than NBR?

Both perform very well with petroleum oils. However, Viton generally offers broader compatibility with synthetic lubricants, fuels, and aggressive chemicals.

Which material lasts longer?

In high-temperature or chemically aggressive environments, Viton typically delivers a longer service life than NBR.

Can NBR replace Viton?

Only in applications with moderate temperatures and limited chemical exposure. For continuous service above 120°C or in aggressive media, Viton is the recommended choice.

Which material is better for hydraulic seals?

NBR is commonly used for standard hydraulic systems because of its excellent wear resistance and cost-effectiveness. Viton is preferred for high-temperature hydraulic systems or chemically demanding environments.

Can you manufacture custom NBR and Viton rubber parts?

Yes. We manufacture custom O-rings, bonded seals, oil seals, gaskets, molded rubber components, silicone products, and precision rubber-to-metal bonded parts according to customer drawings or samples.

Looking For A Reliable NBR & Viton Rubber Seal Manufacturer?

Whether you need standard O-rings or fully customized sealing solutions, our engineering team is ready to help.

We provide:

• Custom NBR, Viton (FKM), EPDM, Silicone, and HNBR seals
• OEM & ODM manufacturing
• Rapid prototyping and tooling support
• Material selection based on your operating conditions
• Competitive factory-direct pricing
• Global export and technical support

Contact Xiamen Jinshun Sealing Technology today to discuss your application, request free engineering advice, receive material recommendations, or get a fast quotation for your next sealing project. Our team is committed to delivering reliable, high-performance sealing solutions that help reduce maintenance costs, improve equipment reliability, and support your long-term business success.