Nd-Fe-B permanent magnets find widespread application in energy conversion devices such as electric motors and generators, as well as in hard-disk drives and loudspeakers. Their high rare-earth (RE) content, typically around 30 wt.%, renders them valuable secondary sources of critical RE elements. Recycling end-of-life magnets, either damaged or compromised by oxidation, has gained momentum in recent years. However, often these magnets remain fully functional even after the devices they are part of are no longer in use. Recovering such magnets from these devices for direct reuse in new applications presents challenges due to the complexity of the devices and the demagnetization required for safe and practical disassembly and handling. Regarding thermal demagnetization, it should be performed under consideration of the intrinsic dependence of magnetic performance on local microstructural specifics, particularly chemical and phase compositions. A major risk associated with thermal treatments exceeding the Curie temperature of the magnets (> 300°C) is the material’s oxidation, which can compromise the process. Additionally, the chemical composition of corrosion-protection surface coatings often proves incompatible with thermal demagnetization procedures. To address these challenges and provide guidance to magnet manufacturers, we investigated the effects of thermal demagnetization on the local chemical and phase composition at the Nd-Fe-B/coating interface. Our study also examined the thermal stability of various coatings and the impact of thermal demagnetization, conducted either in air or under vacuum, on the subsequent corrosion protection efficiency. Special emphasis was placed on conventional coatings such as epoxy resins, zinc, and Ni/Cu/Ni, with the latter emerging as the most promising candidate for future magnet designs.