Wholesale magnet

Selecting the correct material is the foundation of procurement. Neodymium (NdFeB) is the strongest permanent magnet, ideal for compact electronics and motors, but requires Ni-Cu-Ni coating to prevent corrosion. Samarium Cobalt (SmCo) is preferred for high-temperature environments (up to 350°C) like aerospace. Ferrite (Ceramic) magnets are the most cost-effective for low-cost sensors and speakers, while Alnico is best for high-precision instruments requiring temperature stability.

Buyers must confirm the Magnetic Grade (e.g., N35, N52, or 42SH), which determines the energy product (BHmax). Ensure the Remanence (Br) and Coercivity (Hcj) meet your design requirements. For physical dimensions, specify a tolerance of +/-0.05mm for precision components. Additionally, verify the Working Temperature rating, as exceeding this limit will lead to irreversible demagnetization.

For international trade, magnets must comply with RoHS and REACH regulations to ensure they are free from hazardous substances. If the magnets are used in toys or consumer goods, they must meet EN71 or ASTM F963 safety standards regarding magnetic flux strength to prevent ingestion hazards. For quality management, prioritize suppliers with ISO 9001 or IATF 16949 (for automotive grade) certifications.

Since many high-strength magnets are prone to oxidation, the coating quality is critical. Request a Salt Spray Test (SST) report; a standard high-quality coating should withstand 24 to 48 hours of salt spray without corrosion. Common options include Zinc, Nickel, Epoxy, or Gold plating, with Epoxy providing the best moisture resistance for outdoor or underwater use.

Magnets are classified as 'Dangerous Goods' for air freight because they can interfere with aircraft navigation systems. You must ensure the supplier provides a Magnetic Inspection Report and uses Magnetic Shielding Packaging (iron sheets and foam) to reduce the external field strength to below 0.00525 gauss at 15 feet. For sea freight, these restrictions are less stringent but proper labeling is still required.

To ensure transaction security, use Trade Terms like FOB or CIF and conduct payments through secure channels. On Made-in-China.com, look for Audited Suppliers to verify their factory capacity. Always request a Pre-shipment Inspection (PSI) to check the magnetic flux consistency across the batch, as 'grade substitution' (shipping N35 instead of N52) is a common industry risk.

The price of Neodymium magnets is highly dependent on Rare Earth market fluctuations. To secure stable pricing, consider signing long-term supply agreements or purchasing in larger volumes when raw material prices are low. Ask your supplier for a price breakdown including raw material costs and fabrication fees to understand where your money is going.

Verify the correct HS Code (typically 8505.11 for metal magnets) with your customs broker to determine the exact tariff rate. Be aware of Anti-dumping duties that some countries (like the US or EU) may impose on specific magnet types from certain regions. Ensure all Commercial Invoices and Packing Lists clearly state the material composition and intended use to avoid delays.