Neodymium magnets, or rather NdFeB, are products produced by powder metallurgy and based on neodymium, iron and boron, which makes magnets that are impressive in relation to their strong magnetic field. They are actually the strongest permanent magnets that can be produced today.
What is not as well known is that neodymium magnets are susceptible to corrosion in their raw state. When the magnets are exposed to humidity they can corrode, which can destroy the magnet if the magnets are not treated correctly from the outset. The magnets can be surface treated to prevent corrosion.