Yes. Neodymium Iron Boron magnets are sensitive to heat. If a magnet 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. Different grades have different maximum operating and Curie temperatures. See our Neodymium Magnet Specifications Page for more details. Also check out our in-depth article about Temperature and Neodymium Magnets, where we dive into enough technical detail to reveal how this topic is actually a bit more complex. We do stock a range of high temperature magnets, which you can see here.