remagnétisation

Remagnétisation refers to the process of restoring or increasing the magnetic strength of a magnetized object, typically a permanent magnet. Over time, permanent magnets can lose some of their magnetic properties due to factors such as exposure to heat, mechanical shock, or strong opposing magnetic fields. Remagnétisation involves subjecting the object to a strong external magnetic field, usually much stronger than the field it was originally magnetized with, to realign its magnetic domains.

This process is commonly performed using specialized equipment such as magnetizers or demagnetizers used in reverse. For example, a permanent magnet that has weakened can be placed within the coil of a magnetizer, and a strong current pulsed through the coil generates a powerful magnetic field that reorients the magnetic dipoles within the material. The effectiveness of remagnétisation depends on the material properties of the magnet. Some materials are more susceptible to remagnetization than others.

Remagnétisation is a practical technique used in various industries to maintain the performance of magnetic devices. Applications include the restoration of magnets in loudspeakers, motors, magnetic separators, and various scientific instruments. It is also employed in the manufacturing process to ensure magnets meet their specified magnetic strength. The residual magnetism after remagnétisation can sometimes exceed the original magnetization level, though this depends on the material's magnetic saturation point.