PERMANENT-MAGNETS BASED ON R-FE-B AND R-FE-C ALLOYS

A review is given on the basic properties of 2:14:1 hard magnetic phas es as well as technological procedures used for manufacturing R-Fe-B a nd R-Fe-C permanent magnets. First, we analyse the phase diagrams, cry stal structure of hard magnetic phases and composition ranges in which these phases form solid solutions, as a result of various types of su bstitution. Then, the magnetic properties of R2Fe14B-, R2Fe14C- and R2 CO14B-based compounds are described. The routes used for manufacturing R-Fe-B and R-Fe-C permanent magnets are detailed. The magnets' micros tructure as well as their coercivities are described in correlation wi th composition and manufacturing routes. The properties of nanostructu re magnets are then presented. Finally, the stability of Nd-Fe-B and N d-Fe-C magnets in various working conditions is analysed.