How Do Mechanical Seal Materials Affect Performance and Life?

A Complete Guide by Superproof Seals Engineering Pvt. Ltd.

Mechanical seals are critical components in pumps, mixers, compressors, and rotating equipment. Their performance and service life depend heavily on one factor: the materials used in the seal faces, secondary seals, and hardware. Selecting the right material ensures longer uptime, minimal leakage, higher efficiency, and reduced maintenance costs.

At Superproof Seals Engineering Pvt. Ltd., we design and manufacture high-quality mechanical seals for diverse industries, and material selection is at the core of our engineering process.

 

1. Why Material Selection Matters in Mechanical Seals

Each mechanical seal operates under different conditions temperature, pressure, fluid chemistry, speed, and environment. The wrong material can lead to:

• Rapid wear
• Leakage
• Seal face distortion
• Chemical attack
• Equipment failure

Whereas the right material ensures:

• Long seal life
• Lower friction
• High reliability
• Compatibility with process fluids

 

2. Key Mechanical Seal Materials & Their Impact on Performance

The performance of a mechanical seal depends mainly on three categories of materials:

 

1. A) Seal Face Materials

Seal faces are the heart of the sealing process. Their properties—hardness, thermal conductivity, and friction—directly affect seal life.

1. Carbon (Primary Grade / Resin-Impregnated Carbon)

Best for: Water, mild chemicals, low-to-medium pressure pumps

Impact on performance:

• Low friction → reduces heat generation
• Self-lubricating → ideal for dry-running momentary conditions
• Highly corrosion-resistant

Result: Long life in general industrial applications; protects rotating equipment from wear.

 

2. Silicon Carbide (SSIC / RB-SIC)

Best for: Abrasive, high-temperature, corrosive media

Impact on performance:

• Extremely hard → excellent wear resistance
• High thermal conductivity → reduces heat at seal faces
• Chemically inert → suitable for aggressive chemicals

Result: Increased seal reliability in demanding chemical, slurry, and refinery processes.

 

3. Tungsten Carbide (Nickel-Bonded / Cobalt-Bonded)

Best for: High pressure, oil & gas, petrochemical applications

Impact on performance:

• Very strong and impact-resistant
• Suitable for high load and high-pressure environments
• Better for dirty fluids compared to silicon carbide

Result: Durable performance under heavy mechanical stress.

 

4. Ceramic (Alumina Oxide)

Best for: Clean fluids, moderate temperature

Impact on performance:

• Good corrosion resistance
• Low thermal conductivity (may trap heat)
• Commonly used as a mating face with carbon

Result: Economical but limited for high-speed machinery.

 

1. B) Secondary Seal Materials (Elastomers)

These include O-rings, gaskets, and diaphragms. They prevent leakage around shafts and sealing components.

1. Viton (FKM)

• Heat resistant
• Good chemical compatibility
• Used in petroleum-based fluids

2. PTFE / Teflon

• Chemically inert
• Ideal for aggressive acids and solvents
• Not suitable for dynamic O-ring motion

3. EPDM

• Suitable for water & steam
• Poor compatibility with oils

4. Nitrile (Buna-N)

• Economical choice
• Good for oils, fuels
• Limited temperature resistance

Impact on performance:
The right elastomer prevents swelling, shrinking, hardening, or cracking—ensuring long-term sealing integrity.

 

1. C) Metal Components (Hardware Materials)

These include springs, retainers, sleeves, and housings.

1. Stainless Steel (SS 304 / SS 316)

• Most widely used
• Good corrosion resistance

2. Hastelloy / Alloy-20 / Duplex Steel

• Suitable for highly corrosive environments
• Preferred in chemical & offshore industries

Impact on performance:

High-quality metal hardware prevents corrosion, fatigue, and loss of spring elasticity—ensuring consistent seal pressure.

 

 

3. How the Wrong Material Shortens Seal Life

Choosing incompatible materials can cause:

❌ Seal face scoring & uneven wear

❌ Chemical degradation of elastomers

❌ Rapid heat buildup & thermal cracking

❌ Swelling or hardening of O-rings

❌ Premature leakage & pump shutdown

Minor deviations like improper mating face combinations (e.g., carbon vs carbon) can cause catastrophic failure.

 

4. How the Right Material Combination Maximizes Seal Life

The best-performing seal solutions typically use:

✔ Carbon vs. Silicon Carbide

Low friction + high hardness → balanced performance:

✔ Silicon Carbide vs. Silicon Carbide

For aggressive chemicals & abrasive fluids:

✔ Carbon vs. Tungsten Carbide

For high-pressure operations:

✔ PTFE elastomers for corrosive fluids

✔ Viton O-rings for oil-based media

✔ 316 SS or Duplex for high corrosion areas

Using the optimal combination ensures:

• Longer seal life
• Lower operating temperature
• Reduced friction
• Minimum leakage
• Higher pump efficiency

 

5. Material Selection at Superproof Seals Engineering Pvt. Ltd.

At Superproof Seals, we analyze:

• Fluid type & temperature
• Pressure rating
• Shaft speed
• Solid content
• Operating environment
• Industry standards (API 682, DIN, ISO)

Our engineers ensure every seal is manufactured using precisely selected, high-grade materials for maximum durability and reliability.

 

Conclusion

Mechanical seal performance is directly linked to the materials used in its construction. By selecting the right seal faces, elastomers, and hardware materials, industries can significantly improve equipment reliability, reduce leakage, and extend seal life.