Boasting core merits of zero leakage and non-contact transmission, magnetic drive pumps are widely adopted in chemical, pharmaceutical, environmental protection and other fields demanding stringent equipment tightness and operational safety. As two pivotal core components, magnetic materials and containment shells directly determine the corrosion resistance, operational efficiency and long-term stability of pumps. Centering on conveyed medium characteristics, this paper systematically analyzes the matching principles and applicable working conditions of magnetic materials and containment shells, offering references for engineering selection.

1. Magnetic Materials: Balancing Temperature Resistance and Magnetic Transmission Efficiency

Power transmission of magnetic drive pumps relies on magnetic field coupling between inner and outer magnetic rotors. Magnetic performance and temperature resistance of magnetic materials are key factors affecting torque transmission efficiency, load capacity and high-temperature operational stability. Three mainstream industrial magnetic materials are neodymium iron boron, samarium cobalt and ferrite, with distinct performance and applicable scenarios.

1. NdFeB: Featuring high magnetic energy product, superior torque transmission and cost-effectiveness, it is the preferred choice for normal temperature working conditions. Its limitation lies in moderate temperature resistance, with maximum operating temperature no higher than 150℃ for standard grades. It maintains stable magnetic performance and transmission efficiency when conveying dilute sulfuric acid, dilute hydrochloric acid and other common corrosive media below 80℃, suitable for most conventional industrial applications.

2. SmCo: Samarium cobalt delivers greatly enhanced heat resistance compared with NdFeB. The maximum long-term operating temperature of SmCo5 reaches 250℃, while Sm₂Co₁₇ can withstand 300~350℃. It barely suffers magnetic attenuation under high temperatures, fitting all high-temperature medium conveying scenarios. For 180℃ heat conduction oil transportation, SmCo magnets steadily preserve magnetic field intensity, preventing reduced transmission torque and equipment faults caused by heat and ensuring continuous stable operation.

3. Ferrite: Its primary advantage is low cost, yet it has low magnetic energy product and weak transmission capacity, incompatible with high-torque and high-head operations. It is only applied to miniature magnetic pumps and light-load equipment with low head and load, mostly serving auxiliary conveying devices with low efficiency requirements.

Selection Principle: Prioritize cost-efficient NdFeB for conditions below 120℃; adopt heat-resistant SmCo for 120℃~250℃ high-temperature scenarios; choose ferrite to cut costs for miniature pumps and low-load working conditions.

2. Containment Shell Materials: Coordinated Adaptation of Pressure Resistance, Corrosion Resistance and Low Eddy Current Loss

The containment shell acts as a vital sealing barrier between inner and outer magnetic rotors, isolating media and bearing pressure. Material selection shall comprehensively consider pressure resistance, corrosion resistance and low eddy current loss, combined with medium properties, working pressure and rotating speed. Main materials fall into metallic and non-metallic categories.

2.1 Metallic Materials

1. Hastelloy: Possessing high resistivity, high strength and outstanding corrosion resistance, it is ideal for severely corrosive media. For 98% concentrated sulfuric acid conveyance, Hastelloy containment shells cut eddy current loss by over 60% compared with ordinary stainless steel, enduring long-term erosion and scouring.

2. Titanium Alloy: Excellent in chloride corrosion resistance, it effectively resists damage from seawater, brine and chlorine-containing circulating water. It exhibits superior durability and stability in 3.5% sodium chloride simulated seawater, widely used in seawater desalination and marine chemical industries.

3. 316L Stainless Steel: An economical universal material with low cost and good machinability, it meets basic corrosion resistance demands for common conditions. Limited by low resistivity and high eddy current loss, it only suits low-pressure, normal-temperature and mildly corrosive medium transportation.

2.2 Non-metallic Materials

1. Carbon Fiber Composite: Characterized by high strength, wide temperature adaptability and zero eddy current loss, it fits extreme high and low temperature complex conditions. It completely eliminates eddy current loss in high-temperature hydraulic oil delivery, greatly boosting pump efficiency and energy-saving effect.

2. Engineering Plastic: Low-cost and easy to process, it withstands weak acid and alkali corrosion, applicable to general low-pressure and normal-temperature working conditions. Poor heat resistance leads to deformation, aging and damage under high heat, restricting its application scope.

Selection Principle: Use special metals like Hastelloy and titanium alloy for strong acid and alkali media; select carbon fiber composite for high-temperature and high-efficiency required scenarios; adopt engineering plastic to reduce costs for conventional low-pressure normal-temperature operations.

3. Material Matching Cases for Typical Medium Conditions

Practical matching schemes of magnetic materials and containment shells for common industrial working conditions are summarized as follows:

1.98%Concentrated Sulfuric Acid Conveyance: Matched with Hastelloy containment shell and SmCo magnet. Hastelloy resists severe corrosion and lowers eddy loss, while SmCo avoids magnetic attenuation under heat for steady long-term operation.

2. Seawater Desalination Conveyance: Matched with titanium alloy containment shell and NdFeB magnet. Titanium alloy copes with chloride corrosion, and cost-effective NdFeB balances operational reliability and economic expenditure.

3.180℃ High-temperature Heat Conduction Oil Conveyance: Matched with carbon fiber containment shell and SmCo magnet. Carbon fiber realizes zero eddy loss and high-temperature adaptability, and SmCo maintains stable magnetic performance to solve low efficiency and magnetic attenuation issues.

Conclusion

Proper magnetic drive pump selection shall conform to actual working conditions, with magnetic materials and containment shells reasonably matched according to medium corrosiveness and temperature. Rational collocation of the two core components guarantees favorable corrosion resistance, operational efficiency and stability. Practical application shall avoid empirical selection. Scientific material matching enables long-term stable, efficient and energy-saving pump operation, and cuts subsequent maintenance and replacement costs effectively.