High performance isotropic R-(Co,Fe)-C magnets by melt spinning (R= Sm, Pr)

In our search of high performance isotropic magnets for high temperature applications a large variety of quasiternary R$_{x}$(CoFe)$_{100}$-x-y$_{ }$C$_{y}$ alloys with x=10.5-15,y = 0-4.5 were produced by melt-spinning. The alloys were characterized by X-ray diffraction and Scanning and transmission electron microscopy. The Fe substitution for Co and Pr substitution for Sm increases magnetization, while the C addition increases the coercivity. Remanence values of more than 100 emu/g and coercivity of 13 kOe were obtained. The hard magnetic properties are associated with the disordered hexagonal 2:17 compound. The microstucture properties are studied to optimize the properties for high temperature applications. The effects of the alloying elements (Pr,Fe,C) , quenching rate and heat treatments are analyzed and coercivity mechanism are discussed.