Silicon carbide and tungsten carbide mechanical seals: a guide

05.08.2024

Silicon carbide mechanical seals

Mechanical seals with seal rings made of silicon carbide (SiC) are widely appreciated for their outstanding mechanical and chemical properties.

In fact, silicon carbide is a ceramic material that offers numerous advantages in terms of performance and durability. The main characteristics of these mechanical seals include high hardness and wear resistance, making SiC particularly resistant to applications with abrasive conditions. In addition, silicon carbide possesses remarkable corrosion resistance due to its chemical inertness, making it ideal for use in chemically aggressive environments.

Another distinguishing feature of SiC is its high temperature resistance, which enables the seals to maintain their mechanical properties even at high temperatures. The material's low thermal expansion ensures the dimensional stability of mechanical seals, even under extreme thermal conditions. SiC seals also exhibit good tribological properties, with low friction and compatibility with various types of lubricants, improving energy efficiency and reducing wear.

Finally, silicon carbide offers significant resistance to thermal fatigue, being able to withstand repeated heating and cooling cycles without being damaged.

Tungsten carbide mechanical seals

Mechanical seals with seal rings made of tungsten carbide (WC), also known as widia, are also prized for their outstanding mechanical and chemical properties.

Tungsten carbide is a ceramic material that is characterized by high hardness and wear resistance, making it ideal for applications where abrasive conditions are common. In addition, WC offers remarkable corrosion resistance due to its chemical inertness, making it suitable for use in chemically aggressive environments.

This material is also characterized by high temperature resistance, maintaining its mechanical properties even at very high temperatures. Another important characteristic of tungsten carbide is its high compressive strength, which ensures its ability to withstand high loads without deforming. WC mechanical seals also exhibit good tribological properties, with low friction and compatibility with different types of lubricants, thus improving efficiency and reducing component wear.

In addition, tungsten carbide is fatigue resistant, being able to withstand repeated load cycles without significant damage.

Comparison of silicon carbide and tungsten carbide mechanical seals

Silicon carbide and tungsten carbide mechanical seals have different characteristics that make them suitable for specific applications. Silicon carbide is extremely hard, almost as hard as diamond, and offers exceptional wear resistance. However, tungsten carbide is also very hard, but slightly less so than silicon carbide.

In terms of corrosion resistance, silicon carbide excels, making it ideal for chemically aggressive environments. In comparison, tungsten carbide offers good corrosion resistance, but significantly less than its counterpart.

Both materials are suitable for operating at high temperatures, but silicon carbide can handle more extreme temperatures than tungsten carbide. However, when it comes to fracture toughness, silicon carbide is more brittle, while tungsten carbide offers greater strength, making it more suitable for conditions with shock and vibration.

In summary, silicon carbide mechanical seals are preferred for applications that require very high wear and corrosion resistance, and the ability to operate at extremely high temperatures. In contrast, tungsten carbide seals are more suitable for situations where higher fracture resistance is required and shock and vibration are present.

Applications of these two mechanical seals

Silicon carbide (SiC) mechanical seals are used in the following applications:

• Chemical and petrochemical industry: ideal for environments with high chemical aggressiveness, where superior corrosion resistance is essential.
• Water treatment: particularly suitable for water purification and treatment plants due to their excellent resistance to corrosion and wear.
• High-performance gas turbines and engines: used in applications requiring operations at very high temperatures, maintaining stability and performance over time.

On the other hand, tungsten carbide (WC) mechanical seals find applications in the following areas:

• Mining industry: suitable for the extremely abrasive conditions typical of mining and mineral processing operations.
• Oil industry: used in drilling and extraction equipment where mechanical strength and durability are required.
• Heavy mechanical applications: ideal for machinery and equipment operating under high loads and intense stresses.
• Water treatment in less aggressive conditions: appropriate for water treatment plants where conditions are not extremely aggressive, but good wear and corrosion resistance is still required.

Conclusions and the role of Meccanotecnica Umbra

In conclusion, the choice between silicon carbide and tungsten carbide mechanical seals depends strictly on the specific needs of the application. Both materials offer outstanding performance in terms of strength and durability, but it is crucial to consider the environmental conditions and mechanical stresses involved.

In this context, we at Meccanotecnica Umbra are an international reference in the field of mechanical seals. Our team of highly skilled professionals is able to manufacture silicon carbide (SiC) and tungsten carbide (WC) seals either based on original designs or by modifying existing solutions, thus meeting specific customer requirements. Contact us now for more information!