The Study of Cheap R-Fe-B Syetem Sintered Permanent Magnetic Materials

For comprehensive utilization of the rare earth resources in our puntry and to decrease the cost of Nd FeB magnets, the relationshi s between the magnetic properties and composition, processing of the cheap R-Fe-B system permanent magnets have been studied in this paper (R=Pr + Nd, or R=Ce + Pr + Nd). By addition of Al, the coercivity of alloy increases.The optimum magnetic properties of (NdPr)-Fe-B alloy are. Br=1.25T._MHc=714.3kA/m,(BH)m=297.2kJ/m³.The magnetic properties of (PrNd)_1-y Ce_y-Fe-B alloy(y=0~0,5)decrease with increasing Ce content. The magnetic properties are as follows:Br=1.25T, _MHc=825.4 kA/m, (BH)m=297.5kJ/m³ for the alloy of y=0.03; Br=1.20T, _MHc=563.6kA/m, (BH)m=246kJ/m³ for the alloy of y=0.3, Br=1.13T, _MHc=492kA/m, (BH)=222.2kJ/m³ for the alloy of y=0.4; (BH)=174.6kJ/m³ for the alloy of y=0.5. The curie temperature of the alloys is about 609~590K. The reversible temperature coefficient of residual induction is about-0.094~-0.119%/K, The microstructure, density, hardness, specific resistivity of the alloys have been observed and measured respectively.