While neodymium magnets are pound-for-pound the strongest magnets available, extreme temperatures can alter the behavior of their atoms. As a result, their overall strength may fluctuate while they’re in use, creating potential hazards.  Prolonged exposure to these temperatures can also be costly; a neodymium magnet can permanently lose its magnetism when exposed to extreme heat, requiring a replacement and possibly an entire redesign of the environment it’s used in. Before using neodymium magnets for your next project, here’s what you should know about their temperature tolerances.

Effects of Heat on Neodymium Magnets

In general, extreme heat is bad for neodymium magnets. A standard neodymium magnet’s pull begins to decrease at 80°C. As stated above, this can quickly become hazardous in environments where consistent strength is required. The good news: If the magnet is quickly returned to room temperature, its full magnetism will be restored. However, if left at temperatures above 80°C for an extended period of time, magnetism can be permanently lost. In addition, a standard neodymium magnet’s Curie temperature—the temperature at which magnetism is permanently lost—is around 320°C. But these temperatures are only approximate. Just as important in determining heat resistance is the shape of the magnet and the materials used to make it. The shape of a neodymium magnet directly influences how much heat it can withstand. In general, a thin magnet will be more susceptible to heat than a thick, bulky magnet. Meanwhile, the materials within a neodymium magnet can be altered to increase heat resistance. By introducing dysprosium and erbium, some neodymium magnets achieve working temperatures up to 200°C and Curie temperatures up to 370°C. However, these materials have two drawbacks: less overall strength and increased costs.   To achieve a more accurate estimate of a magnet’s heat resistance, we recommend conducting an internal test to determine if a certain magnet will meet your requirements.

Why Heat Impacts Magnets

Under normal temperatures, the atoms that make up a magnet align between the two poles, fostering magnetism. When exposed to heat, however, these atoms begin to move faster and sporadically. This jumbling misaligns the atoms, causing magnetism to be lost.

Effects of Cold on Neodymium Magnets

When compared to heat, cold is much better for magnets. In fact, between 0°C and -138°C, a neodymium magnet’s strength will actually exceed its strength under normal temperatures by up to 2%.       Around -138°C, spin reorientation occurs, decreasing magnet strength. However, the losses sustained at such lower temperatures aren’t nearly as dramatic as they are with heat. Even at -196°C, the boiling point for liquid nitrogen, a neodymium magnet will still have 87% of its normal room temperature strength. In most cases, a cold magnet’s force will return once it warms to normal temperatures.

Why Cold Impacts Neodymium Magnets

Down to -138°C, the atoms in magnets begin to move slower and less randomly. This stability creates a more controlled alignment of the atoms producing the magnetic field. The result: Heightened magnetism. However, at -138°C and colder, spin reorientation causes the magnetization direction to change, decreasing the magnet’s strength. When kept below 80°C, neodymium magnets are powerful, reliable tools. If you’d like to use them in your next project, browse our catalog for a wide variety of shapes, sizes, and designs. If you have additional questions about temperatures or neodymium magnets, contact our team for prompt explanations.