Engineering Longevity: Tungsten Carbide Fusion Coating for Progressing Cavity Pumps

Pumps are essential components in Waste Water Treatment Plants (WWTPs), where equipment reliability and longevity are key to maintaining stable and efficient operations. Regular maintenance, proper monitoring, and selecting right pump materials for specific wastewater conditions help minimize downtime and extend service life. For decades, NETZSCH NEMO Progressing Cavity Pumps have provided proven, efficient solutions for these demanding applications.

The NEMO Progressing Cavity Pump plays a vital role in the municipal market, conveying chemicals, sludge, and sludge cake in water and wastewater treatment plants. As the demand for greater efficiency and reliability increases, continued advancements in design and materials focus on amplifying durability and reducing total cost of ownership. A key aspect of achieving these goals lies in selecting the right pump components and protective options—such as advanced rotor coatings that significantly extend service life.

One such innovation is the NETZSCH N.Durance tungsten carbide fusion coating, characterized by its exceptional hardness and durability. Unlike traditional coatings that may chip, flake under stress, or the base metal being attacked by corrosion, N.Durance tungsten carbide fusion offers a robust surface that maintains its integrity over extended periods, even in very abrasive environments. This is essential for progressing cavity pumps, where the rotor experiences significant friction and wear from the fluids and solids being pumped. The hardness of tungsten carbide, rated around 9 on the Mohs scale, is second only to diamonds. This property ensures that the N.Durance fusion coating can withstand the toughest operational conditions, reduce wear rates, and elevate overall pump operational efficiency and longevity.

Moreover, the proprietary N.Durance fusion coating technique NETZSCH developed to apply tungsten carbide creates a superior metallurgical bond with the base metal, resulting in a coating that is both, resilient and seamlessly integrated into the rotor. This new method NETZSCH developed surpasses traditional HVOF coatings which are not as evenly spread, have higher porosity, cannot be ground as smooth, and just don’t have longevity and the resistance of N.Durance fusion coating. Contrast this with other coating methods (e.g., chrome plating or other surface plating), where the base metal can be attacked, causing the coating to separate due to corrosion of the base metal, ultimately compromising the lifespan of the pumping elements. In comparison, N.Durance is fused into the base metal rather than deposited as a separate plating layer. Pumps fitted with NETZSCH’s N.Durance tungsten carbide fusion-coated rotors demonstrate a significant increase in MTBF (mean time between failures) and a much longer overall service life, resulting in reduced downtime and lower maintenance costs for municipal operations.

Maintenance is a critical factor in the lifecycle of municipal pumps. The exceptional durability of tungsten carbide fusion coatings allows for reduced maintenance requirements, minimizing operational interruptions and extending service intervals. This reliability is especially valuable in municipal applications, where maximizing up-time is essential. Studies have demonstrated that pumps equipped with tungsten carbide fusion coating achieve a significantly lower total cost of ownership, driven by decreased maintenance demands and longer component life. With the new fusion coating process and in-house rotor manufacturing, NETZSCH delivers the highest rotor quality and longevity in the industry. This enhanced rotor performance also extends the service life of the NEMOLAST stator, further improving system reliability. Additionally, for the U.S. market, all components are fully compliant with Build America, Buy America (BABA) requirements.

The contributions of key individuals and organizations have played a pivotal role in advancing the understanding and application of tungsten carbide fusion coatings. Innovators in materials science have worked diligently to heighten the characteristics of tungsten carbide, making it more accessible for widespread industrial use. For instance, NETZSCH researchers have focused on optimizing the deposition processes to ensure uniformity and integrity of the coating while adjusting the composite materials to improve performance in various environments. NETZSCH spent a significant about of time researching and developing the process specifically for Progressing Cavity Pump rotors to take tungsten carbide coating to another level.

From an operational perspective, various stakeholders, including engineers and plant managers, have endorsed the transition to tungsten carbide fusion coatings. Especially those that have tried NETZSCH’s new proprietary process and unique rotor performance. Interviews and feedback from NETZSCH pump users in the municipal sector indicate a growing recognition of the benefits offered by this advanced coating. Engineers have noted improvements not only in the performance of pumps but also in the overall reliability of pumping systems, leading to exceeded expectations in wastewater management and other applications. With a hardness of 1,300 Vickers, it is the hardest rotor coating in the industry. The fusion process is much more environmentally friendly than toxic chrome plating. By replacing chrome plating and improving rotor performance, NETZSCH moves one step closer to its global sustainability goals.

Though some raise concerns about the upfront cost of tungsten carbide fusion coatings, NETZSCH addresses this with three coating levels— N.Durance Advanced, N.Durance Pro, and the top-of-the-line N.Durance Ultimate—giving users flexibility to match performance and budget. When examining the long-term benefits, many find that the upfront costs are justified when considering the lifespan and reduced maintenance associated with these coatings. As municipalities strive to become more cost-effective and efficient, the integration of advanced materials like N.Durance represents a proactive approach to managing resources and reducing repairs and spare parts consumption.

Which spare parts availability is another factor to consider when it comes to maintaining up time for a pump or plant operation. NETZSCH USA is able to make the rotor in house, starting from bar stock and N.Durance fusion coating it in as little as 1-2 days. In addition to availability of parts, predictability is the next step to ensure uptime. With the introduction of NETZSCH’s new smart monitoring technologies (NORIUS) is also able to provide valuable data on pump performance and enabling predictive maintenance for more adept scheduling of operations.

As the demand for sustainable municipal water management continues to grow, the need for reliable and cost-effective solutions will remain paramount. NETZSCH’s N.Durance Tungsten Carbide fusion coatings are positioned to play a key role in these developments by ensuring that progressing cavity pumps can meet increasing operational demands without sacrificing performance or incurring excessive costs.

In conclusion, the N.Durance tungsten carbide fusion coatings offer a formidable solution for NEMO Progressing Cavity Pump rotor effectiveness, abrasion resistance, and longevity in the municipal market. With hardness, reduced maintenance requirements, and lifecycle cost benefits, this rotor coating technology presents a compelling case for widespread adoption. As NETZSCH continues to advance its coating technologies, pump performance and reliability will keep improving—delivering greater value to municipalities and their communities. Ongoing collaboration with users will be key to driving innovation and establishing N.Durance tungsten carbide fusion coating as the preferred standard in the municipal pump market.

N.Durance™, NEMO® and NEMOLAST® are trademarks of NETZSCH Pumpen & Systeme GmbH.