A customs officer holds up your shipment of magnetic connectors and asks one question: "Prove these magnets don't contain controlled heavy rare earth elements." Your answer - or your inability to answer - determines whether the container moves or sits. Low temperature tolerance is not evidence, supplier promises are not evidence, and a surface scan is rarely enough. What regulators actually accept is elemental data from an accredited lab. Here's how to build that case.
Step 1: Get the Right Test - ICP-OES / ICP-MS
For formal compliance documentation that customs and trade inspection authorities will accept, the answer is ICP-OES or ICP-MS performed by a CNAS-accredited laboratory. Two details make or break the report:
Test the bulk, not the surface. The magnet must be crushed and digested so the result reflects the material's overall composition. Measuring only the coating misses the critical case: grain-boundary-diffused magnets carry their dysprosium or terbium precisely at grain surfaces, exactly where a surface-only method is most likely to underreport.
Demand the full element list. The report must quantify samarium (Sm), dysprosium (Dy), and terbium (Tb) - the controlled heavy rare earths - alongside neodymium (Nd) and praseodymium (Pr), which serve as classifiers. This distinction matters: Nd and Pr content identifies whether you're looking at ferrite, an N-grade NdFeB, a Dy/Tb-enhanced grade, or SmCo, each with entirely different regulatory status.
Detection limits in the ppm range mean even trace Dy or Tb additions show up. That is the entire point.
Step 2: Use XRF for What It's Good At - Screening
X-ray fluorescence earns its place on the incoming-inspection bench: it's fast, non-destructive, and ideal for batch screening of magnet deliveries. But understand its limits plainly. XRF reads the surface. It underestimates Dy and Tb in grain-boundary-diffused material, and customs authorities do not accept a standalone XRF result as final determination. Treat it as a filter that decides which lots need confirmatory ICP - nothing more.
Step 3: Assemble the Supporting File
A complete compliance archive pairs the third-party report with supplier documentation:
Material certificate (COA) from the magnet manufacturer, stating the grade and a formal declaration that no Dy, Tb, or Sm was added. Useful for supply-chain traceability - but remember, it's a self-declaration and cannot substitute for an accredited lab report.
Magnetic performance and irreversible demagnetization data - BH curve, operating temperature, demagnetization curve. Use these as reverse screening logic: an SH/UH/EH grade rated for 150–200 °C almost certainly relies on Dy/Tb for coercivity. The inverse is not proof, however. A low temperature rating does not demonstrate the absence of heavy rare earths, and no customs authority will accept that inference.
MSDS listing the material composition.
The Decision Logic for Classification
Ferrite magnets - no rare earth content, no control exposure.
N-grade NdFeB (N35, N42, etc.) - contains light rare earth Nd/Pr but no Dy or Tb, and therefore does not fall under controlled permanent magnet categories. This is the grade of choice when compliance simplicity matters.
M/H/SH/UH/EH/AH grades - formulated with Dy/Tb precisely to survive elevated temperatures. Every lot requires ICP confirmation of actual composition.
SmCo - contains samarium and is directly classified as a controlled primary magnetic material. If your design calls for SmCo, plan the export paperwork accordingly.
Form matters as much as composition. A bare magnet ring or blank is treated as a primary magnetic material. A finished magnetic connector - magnet embedded in the housing, integrated with pogo pins and cable - is a deeply processed end product, and Ministry of Commerce guidance explicitly places items like magnetic charging connectors in this category, outside primary-magnet controls.
Implementation Notes from the Production Floor
In our own work machining magnetic connector assemblies to customer drawings - precision magnet seats, shielding plates, housings for overmolded parts - we've settled on a routine that travels well: the magnet specification sheet carries a clause requiring a CNAS ICP report with Dy, Tb, and Sm below detection limits; every incoming lot is retained and screened, with XRF at receiving and ICP on a rotating basis; and export documentation cites only the third-party elemental results. One further caution for anyone building to N-grade magnets: their lower temperature ceiling means soldering and overmolding processes must keep the magnet itself cool enough to avoid irreversible demagnetization - compliance and process engineering, as usual, arrive at the same table.
Frequently Asked Questions
Q1: Is an XRF screening report sufficient for customs clearance of magnet products? No. XRF analyzes the surface and underdetects Dy/Tb in grain-boundary-diffused magnets. Customs accepts ICP-OES/ICP-MS from an accredited lab as the determination basis. Use XRF internally for batch screening only.
Q2: Can I state in my export paperwork that the low temperature rating proves no controlled rare earths are present? No. Temperature rating is a reverse indicator at best - high coercivity grades usually contain Dy/Tb, but a low rating cannot prove their absence. Only third-party elemental composition data belongs in compliance documents.
Q3: Is the magnet supplier's material certificate enough on its own? No. A COA is a self-declaration. Archive it alongside the CNAS ICP report for a complete file, but the accredited lab result is the evidentiary core.
Q4: We ship fully assembled magnetic charging connectors. Do the magnet control rules even apply to us? Generally not in the primary-material sense. A magnet embedded in an overmolded connector with pogo pins and cable is a deeply processed end product, and trade authorities' published guidance explicitly covers magnetic charging connectors as such. Bare magnet shipments are a different story - classify those as primary magnetic materials.
