Abstract
Permanent magnets are an essential technology for energy conversion. Motors and generators are used to convert energy between electrical and mechanical forms. Permanent magnets must be pre-charged (magnetized) prior to their use in an application and must maintain this magnetization during operation. In addition, permanent magnets must generate sufficient magnetic flux for a given application. Nevertheless, permanent magnets can be demagnetized by a number of circumstances, including the presence of other magnetic materials in their service,1 temperature changes (thermal demagnetization), microstructural degradation, and even the magnet’s own internal demagnetizing field. Therefore, the performance of a permanent magnet can be best understood by examining its ability to withstand demagnetization and to supply the magnetic flux required in a given application. Some of these properties are discussed further. Additive manufacturing, followed by exchange spring magnets will be discussed later.
