Investigation On Preparing And Magnetic Properties Of Co-Based Nano-Amorphous Alloys

In this paper, The Co-Si-B and Co-Zr-B Nano-amorphous alloy powders were obtained by that the aqueous solution of NaBH₄ was added in the solution CoCl₂·6H₂O and NaSiF₆ or the mixing aqueous solution CoCl₂·6H₂O and Zr( SO₄) 2·4H₂O. The compositions,constructions and magnetic properties of the powders were analyzed by Inductively coupled plasma-atomic emission spectroscopy (ICP),X-ray diffraction (XRD),selective area electronic diffraction (SAED),transmission electron microscope (TEM),X - ray Photoelectron Spectroscopy (XPS),differential scanning calorimetry (DSC),and vibrating sample magnetometer (VSM) .In the Co-Si-B system , the samples was preparated by altering the ratio of SiF6-/Co2+. The sample had been studied by means of ICP,XRD,S AED,TEM,DSC,XPS and VSM. It is found that the amorphous alloy powder, having a nearly spherical morphology with diameters of 20-50 nm.By increasing the SiF6-/Co2+ ratio in the original mixed solution, the amount of silicon was found increased. Concerning the XPS study, the surface oxid of element form the alloy distributing inhomogeneous. The important raising of the alloying form Co and Si associated with the decreasing of the oxidized forms of Co and Si along with the ion sputtering, simultaneity ,the two oxidized forms of Si changed.Annealing at 608K and 873K,by the temperature increased, the saturation magnetization increased monotonously from 93.74 to 370.98 emu/g and also the coercivity increased from 31.71 to 60.15 Oe.In the Co-Zr-B ternary system, we studied configuration and Magnetic property after annealing. It is found that the amorphous alloy powder, having a nearly spherical morphology with diameters of 20-60 nm. The XPS showed that the raising of the alloying form Co along with the cleaned times, there is only alloying form existed after cleaned twice times.The alloying form and the oxidized form of Zr and B had no chang nearly .When the annealing temperature increased, the saturation magnetization increased irregularly from 3.10 to 37.14 emu/g, and also the coercivity increased irregularly from 18.58 to 237.64 Oe.When the annealing temperature at 853K,we had the best: the maximum of Bs 37.14 emu/g and the minimum of Hc 49.20Oe after annealed.