High temperature 2 : 17 magnets: Relationship of magnetic properties to microstructure and processing

A comprehensive and systematic study on Sm(CobalFevCuyZrx)(z) magnets is made to completely understand the effects of composition and processing on their magnetic properties. These studies include the compositions required for the formation of cellular/lamellar microstructure, the effects of compositions (x, y, v, z) and processing (aging temperature and time) on microstructure and magnetic properties, the evolution of microstructure and magnetic properties and the magnetic hardening. All of these effects and results may be summed up as changing microstructure and microchemistry, which leads to a variation of the distribution and amount of Cu at the 1:5 cell boundaries. This becomes the most predominant factor controlling the pinning strength and therefore the coercivity and its temperature dependence.