Optimization of Temperature Coefficient of Remanence and Magnetic Properties of Sintered $\hbox{Sm}_{0.7}\hbox{Dy}_{0.1}\hbox{Gd}_{0.2}(\hbox{Co}_{\rm bal}\hbox{Fe}_{0.2}\hbox{Cu}_{0.08}\hbox{Zr}_{0.025})_{7.2}$ Magnets Prepared by Strip-Casting Technique

Rapidly solidified strips were used to produce
${{\rm Sm}_{0.7}{\rm Dy}_{0.1}{\rm Gd}_{0.2}({\rm Co}_{{\rm bal}}{\rm Fe}_{0.2}{\rm Cu}_{0.08}{\rm Zr}_{0.025})}_{7.2}$
magnets with better temperature stability of remanence. The phase and microstructure of strips and ingots were studied by scanning electron microscope (SEM) and X-ray diffraction (XRD). The microstructure of strips showed dendritic crystalline structure. The texture was observed by XRD analysis. Further, microstructure and elements distribution of magnets made with strips and ingots were comparatively studied by transmission electron microscope (TEM) and energy dispersive spectrometer (EDS). Smaller cellular structure was observed in the magnets made with strips. According to the EDS analysis, Gd element homogeneously distributes in the cellular structure, while Dy element tends to distribute in the cell wall phase. By using precursor strips, temperature coefficient of remanence and energy product of sintered magnets is optimized from
$\hbox{-}0.015\%/^\circ{\rm C}$
and 15.76 MGOe to
$\hbox{-}0.01\%/^\circ{\rm C}$
and 16.39 MGOe.