Magnet material

Selecting the correct magnet material depends on the balance between magnetic strength (Br), coercivity (Hcj), and operating temperature. For high-performance applications like EV motors or sensors, Neodymium (NdFeB) is the industry standard due to its high energy product, though it requires surface plating (Ni-Cu-Ni or Zinc) to prevent corrosion. For high-temperature environments exceeding 200°C, Samarium Cobalt (SmCo) or Alnico magnets are preferred for their superior thermal stability. If cost-efficiency is the priority for simple holding applications, Ferrite (Ceramic) magnets offer the best value despite lower magnetic pull.

Buyers must specify the Grade (e.g., N35, N52, 35SH) which dictates both strength and temperature resistance. Ensure the supplier complies with REACH and RoHS standards, as magnets are often used in electronics and must be free of restricted hazardous substances. For international trade, verify the Magnetic Flux density and Dimensional Tolerances (typically +/-0.05mm) to ensure compatibility with precision assemblies. If shipping by air, magnets must meet IATA Packing Instruction 953 to ensure magnetic field leakage is below 0.00525 gauss at 15 feet.

Request a Demagnetization Curve (B-H Curve) report from the supplier to verify the actual magnetic properties against the datasheet. Conduct a Salt Spray Test (SST) for plated magnets to ensure corrosion resistance, especially for NdFeB. For bulk orders, it is critical to perform Pull Force Testing or Gaussian Surface Mapping on random samples. Professional buyers on Made-in-China.com often utilize third-party inspection services to verify that the material composition matches the specified grade before final shipment.

The biggest risk is Magnetic Interference with aircraft navigation systems. You must use Magnetic Shielding Packaging (iron sheets and foam) for air freight. For sea freight, moisture protection is vital; ensure magnets are vacuum-sealed with desiccant to prevent oxidation during long transit times. Additionally, be aware of Intellectual Property (IP) risks, particularly regarding Hitachi patents on certain Neodymium formulations; always confirm your supplier has the legal right to export to your specific region.

Magnet prices are highly sensitive to Rare Earth element market fluctuations (like Praseodymium and Neodymium). Negotiate a Price Adjustment Formula based on public market indices to manage volatility. To ensure transaction security, use Trade Resources on Made-in-China.com and prioritize Audited Suppliers. Always insist on Escrow-based payment terms or Letters of Credit (L/C) for large-scale industrial orders to mitigate financial risk.