Neodymium Iron Boron Temperature Ratings

Temperature Effects on Neodymium Iron Boron, NdFeB, magnets

The Neodymium Iron Boron magnets (NdFeB magnets) are the strongest magnets available. Up to +150 degrees C, they are stronger than the other Rare Earth magnet, SmCo. At around +150 degrees C and above these Neo magnets perform not as strongly as SmCo. The maximum recommended temperature for the NdFeB magnets is +230 degrees C, whereas the SmCo can work at +300 to +350 degrees C.

Neodymium Iron Boron can be used at low temperatures but at around 135 Kelvin (-138 degrees C), the direction of magnetization is said to change from a single axis (easy-axis) to an easy-cone which could cause a fall in output of up to 15% due to this spin reorientation. It is possible to use Neodymium Iron Boron magnets to be used at even colder temperatures but this drop in output will need to be taken into account.

The temperature coefficient of Intrinsic Coercivity (how Hci varies with temperature), b, for Neodymium is approximately -0.6%/degree C (from ambient, but a range of -0.45%/degree C to -0.6%/degree C is possible depending on the Neodymium grade) between +20 and +120 degrees C.

The temperature coefficient of Remanent Induction (how Br varies with temperature), a, for Neodymium is -0.12%/degree C (from ambient, but a range of -0.08%/degree C to -0.12%/degree C is possible depending on the Neodymium grade).

It should be noted that, strictly speaking, these values for a and b actually vary with temperature, and the use of stated values beyond 20 to 120 degrees C may result in inaccuracies when designing (actual BH curves at temperatures assist in clarifying for design purposes).

Temperature characteristics of NdFeB grades

Our guide covers the essential aspects of temperature effects on NdFeB magnets, including:

• Temperature Coefficients: Learn about the temperature coefficient of NdFeB magnets and how it affects magnetic performance across different temperature ranges.
• Maximum Operating Temperatures: Discover the maximum operating temperatures for different grades of NdFeB magnets and how exceeding these limits can lead to irreversible loss of magnetic properties.
• Curie Temperature: Gain insights into the Curie temperature of NdFeB magnets, the point at which they lose their magnetism entirely, and its implications for magnet selection and application design.
• Thermal Management Strategies: Explore strategies for managing heat in applications involving NdFeB magnets, including cooling methods and material selection for enhanced thermal stability.
• Case Studies and Applications: Understand through real-world examples how temperature considerations are integral to the design and selection process for NdFeB magnets in various industries.

How grade choice affects performance when the NdFeB magnet is subjected to heat