Preparation Technology And Property Control Of Fe-Co Gradient Soft Magnetic Materials

Fe-Co alloy has the characteristics of high saturation magnetization,high Curie temperature,low magnetic crystal anisotropy,etc.,which is very suitable for the preparation of devices with high magnetic properties,and has great advantages in reducing the weight or volume of devices.At present,in aviation,aerospace,navigation,military and other high-tech fields have been widely used.With the rapid development of electronic information technology,different materials with unique properties and gradient materials(FGM)that can meet different application requirements are often needed.In order to meet the urgent needs of the development of smart materials,many countries have carried out research on multifunctional composite materials.Fe-cobalt alloys are expected to be used in magnetic gradient materials because of their good magnetic properties.High technology applications require magnetic materials with high performance,small volume and other characteristics,using Fe-Co alloy to prepare a gradient magnetic materials to meet the different performance requirements of magnets,can better reduce the cost and achieve device miniaturization.Because the traditional cold rolling process of Fe-Co alloy can not prepare the Fe-Co gradient material with properties gradient and special-shaped structure,this paper explores the Fe-Co gradient material by the discharge plasma sintering method and powder metallurgy method.In order to explore the influence of Co content on the magnetic properties of Fe-Co alloy,different components of Fe-Co alloy ingots were obtained by changing the amount of Co added in Fe-Co alloy,and the magnetic properties were analyzed.The results showed that:With the increase of Co content,the saturation magnetization of Fe-Co alloy ingot increases first and then decreases,which is mainly caused by the interaction between Fe and Co atoms.The maximum saturation magnetization(M_S)of Fe-Co alloy is about 243.13emu/g when the Co content is 30at.%.With the increase of Co content,the microstructure of Fe-Co alloy changes and its lattice constant decreases gradually.Fe₅₀Co₅₀ and Fe₆₅Co₃₅alloy powders are sintered at different temperatures by means of discharge plasma sintering and powder metallurgy to prepare Fe-Co alloy.The results of XRD,SEM,VSM test and analysis show that:The magnetic properties of sintered Fe-Co alloys are related to their density and grain size.The maximum saturation magnetic induction intensity(B_S)of Fe₅₀Co₅₀ alloy prepared by discharge plasma sintering is about 2.46 T at 950?.Two processes have been used to prepare Fe-Co gradient materials.One of them is the discharge plasma sintering method.By changing the state of the sintered sample,the initial and the end pressure and the sintering temperature,the Fe-Co gradient materials with good mechanical properties and the minimum diffusion depth of 10?12?m have been prepared.The other method is powder metallurgy.By changing the prepressing pressure and prepressing order of the sintered sample,the Fe-Co alloy gradient material with good mechanical properties and minimum diffusion depth of 40?55?m was prepared.The more pores in the diffusion interface,the decrease of mechanical properties would be caused.In order to explore the practical application effect of gradient materials,the Fe-Co alloy was designed as a magnetic core with high power density inductance,and its electromagnetic field was simulated by finite element method.Under the same excitation conditions,the average magnetic induction intensity at the magnetic column of gradient materials composed of Fe₆₅Co₃₅ alloy,Fe₅₀Co₅₀ alloy and both of them were compared.It is found that Fe-Co alloy gradient material used in inductor has higher cost performance than pure Fe-Co alloy.