Magnetism has been known since antiquity but the first real industrial applications began in the thirties.
Ferrites were developed in the sixties and magnetic rare earths (a family of elements such as cerium, neodymium, samarium...) in the seventies (samarium cobalt) and eighties (neodymium iron boron). The powders are simply packed in simple shapes and the obtained magnets are rigid and brittle.
Manufactured by wet or dry pressing, sintering..., magnets are used to generate permanent magnetic or electromagnetic fields. The applications are diverse, from domestic to high-performance devices:
* DC micromotors, synchronous motors, generators, dynamos,
* Telephones, loudspeakers, guitars,
* Switchers, buzzers,
* Coupling devices,
* Toys,
* Stationery,
* Hardware,
* Ore screening.
These pure powder magnets suffer from a common problem: Only simple shapes can be obtained. This has led to the development of polymer magnets which are easy to process by moulding or machining.