Buna vs. Viton: Material Selection
Choosing the right elastomer for sealing applications is critical to system longevity and performance. Among the most popular choices are Buna-N (Nitrile) and Viton (Fluoroelastomer, or FKM), each offering a distinct profile of strengths and weaknesses.
This guide provides a direct comparison of their technical attributes to help you make an informed material selection for your specific application.
1. Buna-N (Nitrile Rubber)
Buna-N is a versatile and widely utilized material, primarily valued for its outstanding resistance to oil, fuel, and other petroleum-based fluids. This makes it the industry standard for general-purpose sealing in automotive and industrial settings.
Key Strengths:
Oil and Fuel Resistance: Excellent performance in contact with hydrocarbon fluids.
Mechanical Properties: Known for good tensile strength and a low compression set, meaning it holds its shape well after being compressed for long periods.
Cost: Highly cost-effective, making it suitable for budget-conscious and high-volume applications.
Key Limitations:
Temperature: Effective in moderate temperature ranges only.
Environmental: Poor resistance to ozone, weathering, and UV light, making it unsuitable for long-term outdoor use.
2. Viton (Fluoroelastomer, FKM)
Viton is a high-performance elastomer designed for demanding environments. It is the preferred material for critical applications in the chemical, aerospace, and high-performance automotive industries due to its exceptional stability.
Key Strengths:
Chemical Resistance: Offers superior resistance to an extremely wide range of aggressive chemicals, including strong acids and solvents.
High Temperature: Provides unmatched thermal stability, with the ability to withstand continuous operating temperatures that far exceed Buna-N.
Environmental Durability: Excellent resistance to ozone and weathering, making it ideal for harsh outdoor or exposed applications.
Key Limitations:
Cost: Significantly more expensive than Buna-N.
Fluid Compatibility: While highly chemical-resistant, it does not perform as well as Buna-N with certain aviation fluids and ketones.
Comparative Analysis and Application Considerations
When selecting between Buna-N and Viton, the decision should be guided by specific environmental and operational parameters (see below).
The choice between Buna-N and Viton is a trade-off between cost and performance.
Choose Buna-N when your application involves exposure to oils and fuels in a moderate temperature range and the budget is a primary concern.
Choose Viton when the application requires superior resistance to aggressive chemicals, high temperatures, or harsh outdoor environments, where material failure is simply not an option.
If you have any questions, please feel free to call us at 770-389-0501.
