Silicon carbide is one of the most commonly used materials for manufacturing mechanical seal faces that are subjected to demanding conditions. Thanks to its mechanical and chemical properties, this material can adapt to a wide range of applications, making it extremely versatile. That said, it is essential to choose the right type of silicon carbide to maximise the durability of seals and avoid potential failures that could lead to downtime, unexpected costs and safety risks.
In many cases, breakdowns in pumps are related to the choice of an unsuitable material for the working conditions. Therefore, it is crucial to understand what benefits silicon carbide brings and which of its varieties best suits each application to minimise maintenance costs and support production continuity. Next, we will go over these and other key aspects of the material:
What is silicon carbide and why is its use so widespread?
Silicon carbide is a compound made of silicon and carbon, known for its high level of hardness and chemical stability. These qualities make it an ideal material for parts subjected to constant friction, such as mechanical seal faces, with particular use in cartridges and process seals.
It also has the ability to maintain its properties even under high temperature and pressure conditions, which reduces the occurrence of breakdowns and extends the life of the equipment. All of this has contributed to it becoming a material of choice for manufacturing mechanical components in sectors like chemicals, petrochemicals, food, water treatment and recycling.
Thanks to advancements in manufacturing processes, it is now possible to produce silicon carbide with different levels of purity and crystalline structure to tailor its properties for each specific application. It is precisely this adaptability that sets it apart from other traditional materials.
These are some of the industries that benefit most from silicon carbide:
- Chemical and petrochemical industries, because of its resistance to aggressive chemicals.
- Water treatment and desalination, due to its resistance to pressure and wear.
- Food and pharmaceutical industries, because of its temperature resistance and good sealing performance.
- Pulp and paper and mining industries, because of its resistance to abrasive fluids.
- Specific models of mechanical seals and cartridges tailored to each need, such as the LRB17 (wastewater treatment plants), LSC40 (any sector), LMS23/LMS27 (chemical sector) and LDC80G/LDC83 (pharmaceutical sector).
Benefits of silicon carbide over other materials
Choosing silicon carbide for the manufacture of mechanical seals provides a number of direct benefits in day-to-day operation. It offers these benefits thanks to its high resistance to abrasive materials where other components wear out quickly. It is fully compatible with pasty, sticky and chemically aggressive substances without compromising performance, resulting in less unplanned downtime and lower maintenance costs. In addition, its high wear resistance allows longer intervals between inspections and improves predictability and safety.
Investing in quality materials like silicon carbide is usually more cost-effective in the medium term than going for cheaper but less durable alternatives. When a breakdown occurs, costs arise from having to buy a new part, labour and the time the production line has to be halted. Therefore, it is important to consider the total cost over the equipment’s lifespan and not just the initial price.
In summary, here are some of the key benefits of this material:
- Longer lifespan of the mechanical seal, even in highly demanding conditions.
- Fewer maintenance shutdowns thanks to its wear resistance.
- Compatibility with abrasive, sticky or chemically aggressive fluids.
- Good performance even at high temperatures and pressures.
- Versatility to adapt to different types of applications.
Types of silicon carbide: which to choose for each application
| Type of silicon carbide | Manufacturing process | Main benefit | Preferred use |
| Sintered silicon carbide | Sintered through a chemical process | Lower manufacturing cost | Mildly aggressive fluids or fluids with low chemical concentrations |
| Sintered silicon carbide with no free silicon | Sintered through heat treatment | Very high chemical resistance | Practically any product, including aggressive ones |
| With graphite | Incorporates graphite particles into the crystal lattice | Better performance with low lubrication | Sticky, pasty or easily vaporised fluids |
| Diamond-coated silicon carbide | Surface coating with diamond particles | Dry operation over short periods | Mechanical seals in vertical reactors |
Sintered silicon carbide
This variant is obtained through a chemical process that reduces manufacturing costs and is an excellent choice for common wastewater treatment applications where efficient solutions are required for fluids with low chemical concentrations or that are not particularly aggressive. In this type of installation, the LRB17 mechanical seal is a particularly suitable solution. Although it does not perform as well under severe chemical attack – and may lose hardness or wear more quickly in highly aggressive environments – it has the distinctive property of being electrically conductive, unlike sintered silicon carbide with no free silicon.
Sintered silicon carbide with no free silicon
In this case, the material is sintered through a heat treatment that creates a much more compact crystalline network. As a result, it offers much superior chemical resistance and can withstand virtually any aggressive product without degrading. Due to its high versatility and long-term reliability, it is suitable for any industrial sector, with the LSC40 cartridge being a key example of this variant. It can be distinguished from chemically sintered silicon carbide because it is an electrical insulator and does not conduct electricity.
Silicon carbide with graphite
This type of carbide incorporates graphite particles into its crystalline structure, which significantly improves its performance in poor or demanding lubrication conditions. It is ideal for processes in the chemical sector, where pasty, sticky or readily vaporising fluids are often handled. Solutions developed with this technology, such as the LMS23 or LMS27 models, can drastically reduce friction at the seal face during critical periods, protecting the seal and preventing unplanned shutdowns, while also allowing operation with gas barriers.
Diamond-coated silicon carbide
It is manufactured by applying a surface coating of diamond microparticles to the seal face, substantially increasing its hardness. This feature allows the seal to run dry for brief periods or operate at low speeds without accelerating wear, making it particularly valuable for applications in the pharmaceutical industry and in seals for vertical reactors. In this high-demand category, the LDC80G and LDC83 models stand out.
Choose the right silicon carbide with the help of Lidering
At Lidering, we not only manufacture rubbing faces, but also provide complete solutions for cartridges and process seals, tailored to complex sectors, such as the recycling industry. We also produce protective sleeves, bearings and silicon carbide rubbing rings to enhance the overall durability of your rotating equipment.
It is essential to consider the intended application, as choosing the most suitable variant will make a real difference to reliability, seal service life, maintenance costs and the reduction of failures.
If you have any questions, contact Lidering and we’ll help you find the solution that best meets your needs.
