Effect Of Nb,Ni Micro-addition On Glass Forming Ability,Magnetic And Magnetocaloric Properties Of Gd₅₀Co₅₀ Alloys

Based on Gd₅₀Co₅₀,the composition of the alloy has been designed by element substitution method in this paper.The target component amorphous ribbon was prepared by single roller melt spinning method.The amorphous forming ability and thermal stability of amorphous soft magnetic alloys were characterized by X-ray diffraction?XRD?and differential scanning calorimetry?DSC?.The integrated physical property measurement system?PPMS?were used to test the magnetic properties as well as the amorphous forming ability and magnetic properties of the alloy after adding a small amount of Nb and Ni.The amorphous forming ability and magnetic properties of the alloys with trace Nb and Ni were systematically studied.The details are as follows:The results show that the amorphous forming ability of Gd₅₀Co₅₀ is poor.Subsequent addition of Nb and Ni elements reduced the glass transition temperature and liquidus temperature of the alloy,and increased the crystallization temperature,thereby improving the amorphous forming ability and thermal stability of the binary Gd₅₀Co₅₀ alloy.Referring to a series of temperature parameters,it is concluded that the addition of Nb is more favorable for improving the amorphous forming ability.And the amorphous forming ability of Gd₅₀Co₄₅Nb₅ alloy is the strongest among the selected alloys.Gd_50-xCo₅₀Nb_x?x=2,5??Gd₅₀Co_50-xNb_x?x=2,5??Gd₅₀Co_50-xNi_x?x=2,5?amorphous alloys have undergone two-stage magnetic phase transition,which has good Soft magnetic properties.The addition of Nb and Ni reduced the Tc of the amorphous alloy.The interaction of Gd atom 3d-4f and Gk factor explained the mechanism of the addition of Tc with Nb and Ni.The FWHM of all the above amorphous alloys under the 5T magnetic field is above 110 K.Among them,Gd₅₀Co₄₅Nb₅ has the best magnetocaloric performance under 5T magnetic field.The magnetic entropy change peak-?S_m^peak is 6.27J g^-1K^-1 and the refrigeration capacity RC is 752.4J g^-1.The magnetic entropy change of Gd_50-xCo₅₀Nb_x?x=2,5??Gd₅₀Co_50-xNb_x?x=2,5??Gd₅₀Co_50-xNi_x?x=2,5?amorphous alloys and magnetic field dependence meets theRelational-?S_m?Hⁿ.The n value is obtained by the direct fitting method and the Kouvel-Fisher method,respectively,and the n value is close to the theoretical value of 0.75 at the Curie temperature.