The operational reliability of magnetically driven pumps depends largely on the quality of the components that make up the support and sliding system. Among these, diamond-coated bushings now represent a highly advanced technological solution capable of preventing one of the most feared risks in industrial plants: dry running.
When the lubricating liquid separating the shaft from the bushings is not present, direct contact between the surfaces can generate intense friction, heat, and rapid, irreversible damage. At CDR Pompe, preventing this phenomenon has become a design priority: adopting diamond coatings on silicon carbide is a concrete step toward ensuring maximum safety for both systems and plant operators.
The goal is not only to reduce product wear but above all to offer our customers and commercial partners guaranteed operational continuity, eliminating the costs and issues linked to unplanned downtime.
DIAMOND-COATED SILICON CARBIDE BUSHINGS AND THRUST RINGS: RSSIC
At the heart of this technology is sintered silicon carbide (SSIC), a material already known for its hardness and chemical resistance, further enhanced by diamond coating. The bushings and thrust rings, together with the shaft, undergo a chemical-physical treatment that deposits an amorphous layer with a crystal lattice similar to that of diamond.
This microcrystalline coating, identified as RSSIC, provides superior resistance to sliding and corrosion, transforming the most delicate points of the pump into ultra-durable components. It is not a simple aesthetic or superficial coating: the diamond layer radically changes the tribological properties of the material, reducing friction and heat generation even under critical operating conditions.
OPERATING PRINCIPLE: HOW DIAMOND-COATED BUSHINGS MAKE THE DIFFERENCE
Under normal operating conditions, magnetically driven pumps work with a thin liquid film that acts as a lubricant between the shaft and the bushings. This film prevents direct contact, reduces friction, and ensures system stability. When the film breaks—due to difficult start-ups, insufficient flow, or the presence of vapors—the system enters a dry-friction regime, with immediate effects on wear. This is where diamond-coated bushings demonstrate their value: the coating drastically reduces the coefficient of friction, minimizes heat increase, and limits damage from direct contact.
SiC pairs with diamond coating have much lower friction coefficients than traditional SiC pairs under dry-running conditions. This means greater safety during unexpected transients and increased tolerance to operational errors.
THE MOST CRITICAL SITUATIONS THAT LEAD TO DRY RUNNING
Every industrial process presents variables that can alter the hydraulic behavior of a pump. The most dangerous variables for a complex system are, of course, those that cannot be predicted, as just a few moments of abnormal operation are often enough to trigger damaging effects throughout the entire infrastructure.
Dry running is therefore not a rare event but a concrete risk that can occur during various stages of the production cycle, from the first start-up to sudden load changes. Analyzing the typical conditions in which the lubricating liquid film disappears is essential to understanding the added value of diamond-coated bushings, which provide a margin of protection when operating conditions become most critical.
• Start-ups with low-boiling liquids, which tend to vaporize quickly and interrupt the liquid film.
• Malfunctions during priming, when the circuit is not yet completely filled.
• Level-control issues on the suction side, leading to voids or air in the fluid.
• Reduced flow rates or nearly closed valves, causing localized heating and reduced lubrication flow.
• Low-viscosity fluids, such as solvents or non-lubricating liquids, which naturally offer less protection against friction.
In all these scenarios, diamond-coated bushings offer an additional safety margin, reducing immediate wear and allowing the pump to resist longer until normal operating conditions are restored.
THE REAL ADVANTAGES OF DIAMOND-COATED BUSHINGS IN MAG-DRIVE PUMPS
The choice of materials used in the internal components of a pump directly affects performance, reliability, and the overall operating costs of the system. In magnet drive pumps—where the absence of mechanical seals already reduces the risk of leakage—the critical point remains the wear resistance of the sliding surfaces.
This is where diamond-coated bushings play a decisive role. The diamond coating not only protects the silicon carbide but enhances its characteristics, making it suitable for managing operating conditions that would challenge traditional materials. This means giving the pump superior resistance and offering our customers reliable performance even in complex or prolonged scenarios.
Key advantages:
• Reduced friction: thanks to the diamond layer, contact between shaft and bushings generates less heat, limiting deformation and damage caused by dry friction.
• Longer component life: the service life of the bushings increases, reducing replacement and maintenance needs.
• Greater tolerance to unexpected events: in cases of problematic start-ups or temporary dry-running conditions, the pumps remain operational without immediate damage.
• Lower operating costs: less downtime means higher productivity and savings on extraordinary maintenance.
• Certified reliability: diamond-coated components deliver consistent performance even with aggressive fluids or high temperatures.
In summary, diamond-coated bushings make CDR magnet drive pumps more robust, efficient, and ready to operate in demanding conditions.
LIMITATIONS AND BEST PRACTICES FOR OPTIMAL USE
It is important to highlight that diamond coating does not make a pump “immune” to prolonged dry running. Even though diamond-coated bushings offer added protection and greater tolerance to unexpected events, they do not replace proper system management and regular maintenance. Essential actions include:
• installing level-monitoring systems,
• checking start-up conditions,
• performing periodic pump maintenance,
• verifying surface finishes and coating integrity,
• adopting safety procedures to minimize risks.
A combined approach—advanced components plus accurate management—is the true key to ensuring maximum system reliability.
DIAMOND-COATED BUSHINGS: AN EXTRA WEAPON FOR PRODUCTION CONTINUITY
Magnetically driven pumps are chosen by customers for their reliability and safety, yet dry running remains one of the most critical challenges for centrifugal pump manufacturers. In this regard, diamond-coated bushings provide a concrete technological response: they reduce friction, extend the lifespan of sliding surfaces, and allow operators to face unexpected events with greater confidence.
While they do not eliminate the need for proper system management, they add a level of protection that can make the difference between costly downtime and uninterrupted production.
To ensure continuity, safety, and top-level performance, CDR designs and manufactures magnet drive pumps equipped with diamond-coated bushings and next-generation materials. Learn more about our services and the customized solutions for your plant: our technical team is available to assist you in selecting the pump best suited to your production needs.