Correlated Magnetics Research prints its patterns on three material families, according to its FAQ: sintered neodymium (NdFeB), sintered samarium cobalt (SmCo), and flexible NdFeB, which CMR says is significantly stronger than a ferrite refrigerator magnet. It publishes typical property data for each.
Sintered NdFeB is the strongest and the default. CMR's neodymium note explains that sintered magnets are anisotropic, meaning they have a preferred magnetization direction; bonded magnets are roughly half as strong but can be moulded in almost any shape and have no preferred direction. Its Demo Kit magnets are 1 inch diameter by 0.125 inch thick, grade N40.
On coatings, CMR says all catalog magnets use nickel-copper-nickel (NiCuNi), that other coatings including PTFE are available for high-volume work, and that SmCo is normally uncoated. Uncoated sintered NdFeB corrodes, so coating choice matters for outdoor, wet or medical environments.
For compliance, CMR's FAQ states that typical neodymium magnets it supplies with the standard NiCuNi coating are RoHS and RoHS II compliant and contain no REACH substances of very high concern. It makes no statement for other coatings and evaluates them case by case.
WholeMagnetics, 2026-10-04. Polymagnet facts are taken from Correlated Magnetics Research’s public pages, listed below; vendor performance figures are CMR’s own.