Q: Will my magnets demagnetise if I heat them?
Yes. Neodymium magnets have a maximum operating temperature of 80℃. Beyond this temperature, the magnet will start to lose magnetic strength at an increasing rate and the subsequent loss cannot be recovered. Coercivity is an important measurement relating to magnetic properties and is used to reflect how well a permanent magnet can resist the demagnetising effects of heat or another magnetic field. The coercivity of a magnet needs to be established before selecting which magnet suits a particular application.
For some applications, alternative magnetic products with better resistance to high temperatures may need to be considered. Ferrite magnets have less magnetic power than a Neodymium magnet of the same size but have a much higher maximum operating temperature of 300℃. Alnico magnets made from alloy can be relatively low strength magnets but can tolerate temperatures up to 800℃ before their magnetic molecular alignment begins to be disrupted and damage the magnet permanently.