Sintered NdFeB Magnet

Overview

Product Specifications

Sintered NdFeB magnets are available in various shapes including blocks, cylinders, rings, arcs, and custom geometries. Dimensions range from millimeters to tens of centimeters, with tolerances as tight as ±0.01mm for precision applications. Key magnetic specifications include remanence (Br), coercivity (HcB, Hcj), maximum energy product (BH)max, and Curie temperature (Tc). Mechanical properties such as density, hardness, and flexural strength are also critical specifications.

Product Grades

According to international standards (e.g., IEC 60404-8-1), sintered NdFeB grades are designated by (BH)max in MGOe followed by letters indicating maximum operating temperature and coercivity. Common grades include N35-N52 (standard temperature, 80°C), 35M-50M (100°C), 35H-48H (120°C), 35SH-45SH (150°C), 30UH-40UH (180°C), 30EH-38EH (200°C), and 28TH-35TH (230°C). Higher numbers indicate greater magnetic energy, while suffix letters denote improved temperature stability.

Coatings

To prevent corrosion, sintered NdFeB magnets require protective coatings. Common options include: Nickel-Copper-Nickel (Ni-Cu-Ni) plating (most widely used, good corrosion resistance), Zinc (Zn) plating (economical, basic protection), Epoxy coating (excellent corrosion resistance, suitable for harsh environments), Gold (Au) plating (for specialized applications like medical devices), and Parylene coating (thin, uniform, biocompatible). Salt spray test resistance ranges from 24 hours (Zn) to over 1000 hours (specialized coatings).

Application Scope

Sintered NdFeB magnets are used across industries: Electronics (hard disk drives, smartphone vibration motors, speakers), Automotive (electric vehicle motors, EPS systems, sensors), Renewable Energy (wind turbine generators, magnetic levitation systems), Industrial Machinery (servo motors, magnetic separators, actuators), Medical Devices (MRI machines, dental tools, drug delivery systems), Aerospace (satellite components, guidance systems), and Consumer Products (headphones, magnetic clasps, power tools).

Packaging Information

Standard packaging includes: Small magnets in anti-static plastic bags or trays, placed in cardboard boxes with foam inserts to prevent movement. Bulk packaging uses rigid cartons with dividers or vacuum-sealed bags. For large/heavy magnets, wooden crates with padding are used. Magnetic shielding packaging (steel or mu-metal sheets) is required for air transport to comply with IATA regulations. Each package is labeled with magnet grade, dimensions, quantity, coating type, and handling instructions ("Keep Away from Electronics").

Common Questions

· Corrosion Resistance: Why do magnets rust? NdFeB contains iron which oxidizes; proper coating selection is critical for longevity.

· Temperature Limits: What happens if overheated? Irreversible demagnetization occurs above the maximum operating temperature (varies by grade).

· Magnetization Direction: Can magnets be magnetized in any direction? No, sintered NdFeB is anisotropic and must be magnetized along the preferred direction.

· Handling Safety: Are there risks? Strong magnets can pinch skin, damage electronics, and affect pacemakers. Keep away from children.

Recycling: Can NdFeB be recycled? Yes, rare earth elements can be recovered through specialized recycling processes.