In this paper,SmCo6.9Hf0.1as-cast alloys and ribbons with the addition of either graphite(C)or carbon nanotubes(CNTs)were prepared by arc melting and melt-spinning,respectively.The effects of adding carbon on the structure and magnetic properties SmCo6.9Hf0.1were investigated by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),magnetic force microscopy(MFM)and vibrating sample magnetometer(VSM).It was found that the microstructure and magnetic structure of SmCo6.9Hf0.1ribbons were changed obviously due to the introduction of C or CNTs,although their crystal structure was characterized as the same Sm(Co,Hf)7single phase,no matter carbon was added or not.As a result,the magnetic properties of carbon-contained ribbons were enhanced in a certain degree.This was considered to be related to the refined equiaxed grains,small domain size and the pinning effect of C or CNTs-rich regions.The magnetic properties of SmCo6.9Hf0.1(CNTs)0.05ribbons reached Hc=12.5 kOe,Mr=57.0 emu/g and Mr/M2 T=0.788.
