Preparation And Magnetocaloric Properties Of Fe-Zr-B-RE Quaternary Amorphous Alloy

In this paper,a series of Fe-Zr-B-RE(RE=Dy,Tb,Gd)quaternary alloys were prepared by the electromagnetic induction melting and single roll spinning method.The effect of Dy,Tb,and Gd element addition on the glass forming ability(GFA),magnetic properties,magnetic entropy change,and corrosion resistance of the Fe-Zr-B amorphous alloy was studied systematically.Firstly,the influence of the addition of Dy,Tb,and Gd elements on the GFA of Fe₈₉Zr₇B₄ alloy was studied.The X-ray diffraction(XRD)was used to analyze the structures of Fe₈₇Zr₇B₄RE₂(RE=Dy,Tb,Gd)and Fe_89-xZr₇B₄Dy_x(x=0,1,2,3,4)ribbons.And the differential scanning calorimetry(DSC)analyses of the amorphous alloys samples are also performed.As a result,glass transition temperature T_g,crystallization temperature T_x,and liquidus temperature T_lwere obtained.The corresponding supercooled liquid region?T_x,reduced glass temperature T_rg,and?parameters were calculated through the characteristic temperature,and the GFA of these alloys was investigated.The results show that the GFA of Fe₈₉Zr₇B₄ alloy can be enhanced by adding Dy and Gd element.In addition,the study of the magnetic properties of Fe₈₇Zr₇B₄RE₂(RE=Dy,Tb,Gd)metallic glass ribbons shows that the saturation magnetization are reduced by adding Dy,Tb and Gd elements.The adding of heavy rare earth elements can improve inner magnetic interaction of the alloy,driving the M-T curves to the positive-temperature direction.The magnetic entropy change peak-?S_m^peak and refrigeration capacity(RC)indicate the improvement of the magnetic refrigeration capacity of the system attributed by the addition of Dy,Tb,and Gd.Secondly,the effect of replacing Fe with different amounts of Dy on Fe₈₉Zr₇B₄alloys was studied.It is found that the GFA of these alloys is strengthened gradually with the increase of Dy.The relevant magnetic properties test of Fe_89-xZr₇B₄Dy_x(x=1,2,3,4)amorphous ribbons shows a second-order magnetic phase transition of the system alloy.The magnetic hysteresis under 50 K is almost zero by analyzing the amplified hysteresis loop near the zero field and the magnetic entropy peak of the system increases with the increased adding of the Dy,indicating the addition of Dy is helpful to improve the magneto-caloric properties of these alloys and the energy loss can be reduced.Finally,the corrosion resistance in a pure water environment of Fe-Zr-B-RE alloys was studied.After replacing the Fe element with Dy,Tb,and Gd elements in the Fe₈₉Zr₇B₄ alloy,the self-corrosion current of the alloy was decreased and the corrosion voltage increased,indicating that the corrosion resistance of these alloys is improved.And the self-corrosion current density I_corr of Fe₈₉Zr₇B₄,Fe₈₇Zr₇B₄Dy₂,Fe₈₇Zr₇B₄Tb₂,and Fe₈₇Zr₇B₄Gd₂ alloys is 1.086?A/cm² 0.389?A/cm²,0.275?A/cm²,and 0.235?A/cm²,respectively,and the corrosion voltage U_corr is-0.549-0.388,-0.35,and-0.288V respectively.The radius of the Nyquist semicircle of the alloy shows an increasing trend.The I_corr of Fe_89-xZr₇B₄Dy_x(x=1,2,3,4)alloy system is 0.525,0.389,0.299,and0.282?A/cm²,respectively,and the corrosion voltage is-0.442,0.388,-0.363,and-0.319 V.The decreasing of corrosion current density and increasing of corrosion voltage,indicating that the introduction of Dy can effectively improve the corrosion resistance of the alloy.