bedrijfsnieuws over Best Materials for Acid-Resistant Seals in Chemical Industry

In chemical processing systems, sealing materials are constantly exposed to strong acids, high temperatures, and corrosive media. Selecting the right acid-resistant seal material is critical to preventing leakage, reducing maintenance, and ensuring long-term system reliability.

This guide compares the best materials for acid-resistant seals and explains how to choose the right one for your application.

Key Requirements for Acid-Resistant Seals

Before selecting a material, it is important to understand the operating conditions:

• Type of acid (H₂SO₄, HCl, HNO₃, etc.)
• Temperature and pressure
• Exposure duration (continuous vs intermittent)
• Mechanical conditions (rotation, friction, load)

Chemical resistance alone is not enough—mechanical performance must also be considered

1. PTFE (Polytetrafluoroethylene)

Best for: General chemical corrosion environments

PTFE is one of the most widely used sealing materials in the chemical industry.

Advantages:

• Chemically inert to most acids, alkalis, and solvents
• Wide temperature range (-200°C to 260°C)
• Very low friction (ideal for dynamic seals)

Limitations:

• Can creep under load (cold flow)
• Lower mechanical strength compared to ceramics

Typical applications:

• Acid pipelines
• Valve seals
• Chemical processing equipment

2. Silicon Carbide (SSiC)

Best for: Strong acids + high wear + high temperature

Pressureless sintered silicon carbide (SSiC) is one of the most advanced sealing materials.

Advantages:

• Extremely high corrosion resistance
• No free silicon phase (no weak points for corrosion)
• High hardness and wear resistance
• Suitable for high-speed and high-pressure systems

Performance:

• Handles strong acids (H₂SO₄, HCl, HNO₃)
• Excellent for abrasive and particle-containing media

Typical applications:

• Mechanical seal faces
• Chemical pumps
• Reactor systems

3. Graphite

Best for: High temperature + moderate chemical exposure

Graphite is commonly used in high-temperature sealing environments.

Advantages:

• Excellent thermal resistance (very high temperature capability)
• Good chemical resistance in many environments

Limitations:

• Vulnerable to strong oxidizing acids (e.g., nitric acid, sulfuric acid)

Typical applications:

• Steam systems
• Heat transfer systems

4. FFKM (Perfluoroelastomer)

Best for: Extreme chemical environments (high-end option)

Advantages:

• Near-universal chemical resistance
• High temperature capability (~300°C)
• Elastic sealing performance

Limitations:

• Very high cost
• Used mainly in critical applications

Typical applications:

• Semiconductor industry
• High-purity chemical systems

5. Elastomers (FKM, EPDM, NBR)

✅ Best for: Mild to moderate chemical environments

Advantages:

• Good flexibility and sealing performance
• Cost-effective

Limitations:

• Limited resistance to strong acids
• Performance highly dependent on formulation

 Typical applications:

• Water treatment
• Low-corrosion environments

Material Comparison Summary

How to Choose the Right Material

Choose PTFE if:

• You need broad chemical compatibility
• Low friction is important

Choose SSiC if:

• Strong acids + high temperature
• Wear and long service life are critical

Choose Graphite if:

• High temperature is the main concern
• Chemical exposure is moderate

Choose FFKM if:

• Extreme chemical + high-end application
• Budget is not a constraint

Common Selection Mistakes

• Choosing elastomers for strong acids
• Ignoring temperature effects on corrosion
• Overlooking wear in dynamic seals
• Selecting based only on cost

Conclusion

There is no single “best” material for all applications. However:

For most chemical industry sealing applications:

• PTFE is the standard choice
• SSiC is the best option for harsh conditions
• FFKM is used for extreme, high-value systems

Selecting the right material based on chemical, thermal, and mechanical conditions ensures long-term reliability and lower total cost.

Need Help Selecting Seal Materials?

If you are working with corrosive media, providing the following will help determine the best solution:

• Chemical composition
• Temperature and pressure
• Seal type (static / dynamic)
• Service life requirements

Custom material recommendations can significantly improve performance and reduce downtime.