Low cost, yet relatively high stength, the most widely used permanent magnets today. Hard to machine. Ferrite magnets are highly resistance to demagnetization and rust. And it can work at 250�Ž. Ceramic magnets are very hard and brittle, and require specialize machining techniques.Anisotropic grades are oriented in the manufacuturing direction, and must be magnetized in the direction of orientation. Isotropic grades are not oriented and can be magnetized in any direction.