Effect On Additional Elements On Sm-Co Based Magnetic Materials

Traditional Sm-Co-based magnetic alloys with low Sm content have excellent high-temperature magnetic properties while Sm-Co-Al alloys with high amounts of Sm possess superior amorphous forming ability.However,few people have detailedly studied the amorphous forming ability and magnetic properties of Sm-Co-based alloys with low Sm content.In this paper,alloying is used to fabricate the Sm-Co-based amorphous alloys with low Sm content by adding other elements,which also provides a new research interests for developing new hard magnets.The arc-melting method,melt-spinning method and crystallization process have been used to prepare the amorphous and nanocrystalline composite materials.Then the phase compositions,microscopic structure and properties of those ribbons are detected by X-ray diffractometer,scanning electron microscope,high-resolution transmission electron microscope,vibrating sample magnetometer and other instruments.The influence of crystallization technique and the addition of B or Fe on microstructure and magnetic properties of melt-spun ribbons are emphatically studied.The results show that addition of B improves the glass forming ability?GFA?of Sm₁₂Co_76-xFe₄Zr₇Cu₁B_x ribbons.Meanwhile,the coercivity of the ribbons gradually increases with the increasing of B content.But excessive B addition?x?5.1?leads to the decrease of the GFA and coercivity of the ribbons.The ribbons with 5at%B addition have optimum coercivity of Hc=19.2kOe.The microstructure of the ribbons is made up of amorphous phase and nanocrystalline phase,and the nano-scale grains whose size is less than 10nm disperse in the amorphous matrix.The demagnetization curves of the ribbons show the characteristic of single hard magnetic phase.When the Sm₁₂Co_71.1Fe₄Zr₇Cu₁B_4.9ribbons were annealed at different temperatures for 30 min,the coercivity of the ribbons increases with temperature rising from 600°C to 700°C.However,the coercivity of the ribbons declines because of phase decomposition when the annealing temperature reaches to 800°C.The ribbons annealed at 700°C for 30 min possess the highest coercivity?Hc=19.7kOe?.The increase of Fe addition is helpful to the formation of amorphous phase in Sm₁₂Co_75-xFe_x Zr₇Cu₁B₅ ribbons,especially the ribbons with 12at%Fe addition acquire an entire amorphous structure.With Fe increment,the coercivity and remanence ratio of the ribbons decrease while the saturation magnetization improves.