Nd-Fe-B Permanent Magnets for Passive and Hybrid Magnetic Bearings with Extended Application Temperature Range

Passive magnetic bearings or hybrid passive magnetic bearings are commonly built up with Sm-Co or with Nd-Fe-B magnets. One of the most important item of those magnets is it’s homogeneity in flux density distribution and the precise angularity. A miss-match would cause an undesired displacement. It may therefore be very important to measure these homogeneity’s and angular deviation very precisely. Some application call for a higher temperature, thus a need of higher remanence Br is inevitable and in some cases the temperature coefficient Tk of remanence Br is also of importance. This may be achieved by applying the Grain Boundary Diffusion GBD. In the following paper we will give an overview of the current development to ensure this future demand. A variation of parameter studies will give an overview of the main influencing factors which act on the bearing forces and stiffness.