What Are Anti Eddy Current Disc Round NdFeB Magnets?
Our disc round anti eddy current neodymium iron boron (NdFeB) magnets are high-performance permanent magnets renowned for an extremely high magnetic energy product and excellent intrinsic magnetic properties. Engineered to resist eddy current effects, these magnets deliver stable performance after professional surface treatment, boasting enhanced corrosion resistance and reliable temperature stability for long-term use.
Available in custom shapes and precise sizes, our NdFeB disc magnets are the ideal choice for compact, high-efficiency magnetic solutions across industrial and commercial applications, with consistent magnetic output even in demanding working environments.
Key Features of SDM NdFeB Disc Magnets
Ultra-high magnetic energy product and superior magnetic performance
Anti eddy current design for stable operation in dynamic magnetic circuits
Enhanced corrosion resistance via professional surface coating treatment
Reliable temperature stability for diverse working conditions
Customizable sizes and dimensions to meet bespoke application needs
High precision manufacturing for tight tolerance requirements
Production Techniques of NdFeB Disc Magnets
We adopt two mature, industry-leading production processes to manufacture NdFeB disc magnets, each tailored to different application scenarios and performance requirements:
Sintered NdFeB Magnets
The most common and high-performance production method: fine NdFeB powder is pressed into disc molds and sintered in a vacuum/inert atmosphere, then precision machined and magnetized. Sintered disc magnets deliver the strongest magnetic fields, ideal for high-demand industrial applications (note: sintered NdFeB is brittle and requires precise processing).
Bonded NdFeB Magnets
NdFeB powder is mixed with a high-quality polymer binder, then formed into disc shapes via compression or injection molding. Bonded disc magnets are less brittle, easy to produce in complex small sizes, and suitable for mass production of standard or custom disc magnets (with slightly lower magnetic properties than sintered types).
Process Steps of Neodymium Magnet
Beyond the basic process framework, each step of neodymium magnet production is strictly controlled to ensure ultra-high magnetic performance and consistency, especially for anti eddy current disc magnets:
Weighing
Precision electronic scales are used to measure rare earth elements (neodymium, praseodymium), iron, boron, and optional additives (dysprosium, terbium) with a tolerance of ±0.01%. This precise proportioning is the foundation for determining the magnet’s grade (e.g., N52) and temperature resistance.
Melting
The weighed raw materials are melted in a vacuum induction furnace at 1,300–1,500°C, avoiding oxidation and ensuring the formation of a uniform Nd2Fe14B main phase alloy ingot—the core of magnetic performance.
Primary & Fine Pulverization
Primary Pulverization: The alloy ingot is crushed into 300–500μm coarse powder via hydrogen decrepitation (HD), a green and efficient method that utilizes hydrogen absorption to split the alloy.
Fine Pulverization: The coarse powder is ground into 3–5μm fine powder in a jet mill under a nitrogen protective atmosphere, ensuring the powder particles are uniform and ready for pressing.
Pressing
In a magnetic field orientation press, the fine powder is compacted into disc blanks while being aligned with the magnetic field. This step locks in the magnetization direction (e.g., axial for disc magnets) and ensures maximum magnetic energy product.
Sintering & Tempering
Sintering: Blanks are sintered in a vacuum furnace at 1,050–1,100°C to achieve densification, forming a solid magnet structure.
Tempering: Two-stage tempering (900°C + 500°C) is applied to optimize the microstructure, significantly improving coercivity and demagnetization resistance—critical for anti eddy current performance.
Machining
CNC grinding machines and wire EDM are used to process the sintered magnets into precise disc sizes (OD/ID/thickness) with a tolerance of ±0.05mm. For anti eddy current magnets, special slotting or laminating processes are added at this stage to suppress eddy current generation.
Surface Treatment
A pre-treatment (degreasing, pickling) is followed by the selected coating process. For harsh environments, Ni-Cu-Ni triple-layer coating is electroplated to provide salt spray resistance of over 1,000 hours, while Black Epoxy is ideal for insulation and anti eddy current reinforcement.
Magnetization
High-voltage pulse magnetizers are used to magnetize the magnets to saturation according to the designed direction (e.g., axial magnetization for standard disc magnets). Anti eddy current disc magnets are tested for magnetic uniformity after magnetization to ensure stable performance.
Packaging & Shipping
Magnetized magnets are packaged with anti-magnetic isolation materials and EPE foam to prevent collision damage. For bulk orders, vacuum packaging with desiccants is used to avoid corrosion during transportation.
NdFeB Magnet Grades & Protective Coatings
Our comprehensive range of grades and coatings is engineered to match the specific demands of anti eddy current disc NdFeB magnets across diverse applications. Here’s a practical selection guide to simplify your decision-making:
1. Grade Selection: Tailored to Temperature & Performance Needs
Each grade is classified by magnetic strength (N35–N52) and temperature resistance (M/H/SH/UH/EH), defined by the maximum operating temperature:
| Grade Series | Max Operating Temperature | Ideal Applications for Disc Magnets |
| N (Standard) | 80°C | Consumer electronics, low-power speakers |
| M | 100°C | General industrial motors, acoustic equipment |
| H | 120°C | Automotive sensors, mid-temperature motors |
| SH | 150°C | High-power EV motor components, industrial automation |
| UH | 180°C | Aerospace instruments, high-temperature sensors |
| EH | 200°C | Extreme-environment industrial equipment, medical sterilization devices |
| Note: Dysprosium is added to H/SH/UH/EH grades to enhance coercivity, making them resistant to demagnetization at high temperatures—essential for anti eddy current magnets in high-heat motors. |
2. Coating Selection: Balanced Corrosion Resistance & Functionality
For anti eddy current disc magnets, coating choice is not only about corrosion protection but also about electrical insulation (a key factor in eddy current suppression):
Ni-Cu-Ni (Triple-layer): Our most popular option—excellent corrosion resistance (1,000+ hours salt spray), high hardness, and moderate insulation. Ideal for automotive and industrial motors.
Black Epoxy: Superior electrical insulation (critical for anti eddy current performance) and chemical resistance. Perfect for high-frequency motors and medical devices.
Zn/Sn: Cost-effective options with good corrosion resistance, suitable for low-cost consumer electronics and audio equipment.
Au/Ag: Premium coatings for high-precision medical devices, aerospace components, and electronic sensors—offering excellent conductivity and corrosion resistance.
Phosphated: Provides basic corrosion protection and insulation, ideal for temporary use or low-cost industrial applications.
Magnetization Directions for N52 NdFeB Magnets
Axially-Magnetized
Axially-Multipole-Magnetized
Diametrically-Magnetized
Diametrically-Multipole-Magnetized
Skewed-Magnetized
Radially-Magnetized
Industrial Applications
Thanks to their compact size, ultra-strong magnetism and anti eddy current performance, our disc round NdFeB magnets are widely used across core industries where high magnetic efficiency is required:
Electric Motors & Automotive: EV motors, automotive components, small industrial motors
Acoustic Equipment: High-fidelity speakers, microphones, acoustic transducers
Medical Devices: Precision medical instruments, diagnostic equipment
Electronics: Hard disk drives, consumer electronics, precision sensors
Other Industrial Uses: Magnetic assemblies, automation equipment, aerospace components
Our Advantages
High-Grade Material Formulation: Refined NdFeB alloy composition, optional dysprosium addition for enhanced high-temperature coercivity and demagnetization resistance
Strict Quality Control: 100% magnetic flux measurement, dimensional inspection and performance testing for every batch
Customization Capability: Full customization of sizes, grades and surface treatments to match your exact application needs
Reliable Performance: Stable magnetic output, corrosion resistance and temperature stability for long service life
The Development & Innovation of NdFeB Magnets
First independently developed in 1982 by General Motors and Sumitomo Special Metals, NdFeB magnets have revolutionized modern magnetic technology with properties superior to traditional permanent magnet materials. Over the decades, we have refined material formulations and processing techniques to address early limitations (e.g., low corrosion resistance, poor high-temperature performance) — including adding dysprosium to boost coercivity for high-temperature applications.
We remain committed to sustainable innovation, focusing on reducing rare earth element reliance (e.g., dysprosium) without sacrificing performance, and optimizing production processes for lower environmental impact. Our anti eddy current disc NdFeB magnets represent the latest in this innovative legacy, blending high performance with practical industrial usability.
Customization & Order
We accept small and large quantity orders (MOQ 1 piece) for our anti eddy current disc round NdFeB magnets. Contact our team to inquire about custom grades (N35-N52, N35M-N50M, N35H-N48H, etc.), surface coatings (Ni-Cu-Ni, Zn, Sn, Black Epoxy, etc.) and dimensional specifications — we will provide a tailored magnetic solution for your project.
