Yes. Although they have the highest magnetic field strength and have a higher coercivity (which makes them magnetically stable), neodymium magnets have a lower Curie temperature and are more sensitive to heat and vulnerable to oxidation than samarium-cobalt magnets.
While neodymium magnets have been proven to retain their effectiveness up to 80°C or 176°F, this temperature may vary depending on the grade, shape and application of the particular magnet. High temperature grades of neodymium magnets are available for applications that may expose the magnets to heat above the normal maximum operating temperature.
If a magnet is heated above its maximum operating temperature (176°F/80°C for standard N grades) the magnet will permanently lose a fraction of its magnetic strength. If they are heated above their Curie temperature (590°F/310°C for standard N grades), they will lose all of their magnetic properties.
Corrosion can cause unprotected magnets to shed their coating and crumble into a powder. Use of protective surface treatments such as gold, nickel, zinc and tin plating and epoxy resin coating can provide corrosion protection.
Our magnets are finished with a three-layer nickel/copper/nickel plating, and this coating provides enough protection for most applications. But remember, neodymium magnets are not waterproof. They will rust or corrode in the presence of moisture. If used underwater, outdoors or in a moist environment, they can corrode and lose magnetic strength.
If you need magnets for applications that may expose them to moisture, consider trying our sewing magnets which are encased in PVC to protect them. We also have other coating options available which are weather resistant, contact us for more information.