NdFeB permanent magnets are a key material in modern magnets, known for having the highest energy density among commercially available options. Their strength comes from the Nd2Fe14B phase, which gives strong directionality and high magnetization. They are made through careful powder metallurgy and sintering, starting with pure materials in inert or vacuum conditions, followed by forming and aligning the crystal axes with a strong magnetic field to create a material with high remanence. Heat treatment and controlled microstructure improve coercivity and stability under stress. Microstructure, including grain size and boundaries, strongly affects performance, with diffusion methods using heavy rare earth elements used to boost high-temperature behavior. Because they can corrode, surface coatings such as nickel, epoxy, zinc, or multilayer systems are applied to protect them without reducing magnetism. These magnets are used in electric vehicles, wind turbines, motors, robotics, medical devices, and precision electronics.
