Following machining, many magnets undergo a coating or surface treatment process. This is particularly important for rare earth magnets like neodymium, which are highly susceptible to corrosion. Common coatings include nickel, zinc, epoxy, gold, and plastic. These coatings not only protect the magnet from environmental factors such as moisture and chemicals but also improve the magnet’s durability and appearance. In applications where hygiene is important, such as medical devices, specialized biocompatible coatings may be used.

Another critical step in magnet manufacturing is magnetization. This process involves exposing the finished magnet to a strong external magnetic field, usually generated by a coil or solenoid, to align the internal domains permanently. The strength and direction of the magnetic field applied during this step define the magnet's performance in practical Plate Magnets use. Once the magnet has been fully magnetized, it is tested for various parameters such as field strength, polarity, and mechanical tolerances to ensure quality and consistency.

Quality control plays an essential role in magnet manufacturing. Advanced measuring instruments are used to test the magnetic field strength, coercivity, remanence, and maximum energy product. These parameters are crucial in determining whether the magnet will perform as expected in its intended application. Non-destructive testing methods such as magnetic flux mapping, X-ray diffraction, and electron microscopy are also employed to detect internal flaws and inconsistencies. Only magnets that pass stringent quality checks are approved for shipment to customers.

The manufacture of magnets also varies depending on the type of magnet being produced. For example, ferrite magnets, which are made from iron oxide and strontium or barium carbonate, follow a slightly different process that includes calcining the raw materials, pressing them into shapes, and firing them in kilns. Ferrite magnets are inexpensive, corrosion-resistant, and widely used in motors and loudspeakers. On the other hand, alnico magnets are produced through casting or sintering and are known for their high temperature stability and resistance to demagnetization, making them ideal for sensor applications.