γ'-Fe4N软磁复合材料的磁性及损耗特性

Magnetic and loss characteristics ofγ'-Fe_(4)N soft magnetic composites

软磁复合材料在光伏逆变器、新能源汽车及充电桩等新兴电力电子行业的应用前景广阔.目前研究者们聚焦于开发新型软磁复合材料,达到匹配以SiC和GaN为主的第3代高频宽禁带半导体的目标.本文利用氨气氮化羰基铁粉制备得到高电阻率的γ’-Fe_(4)N,并证实其具备优异的软磁性能,对γ’-Fe_(4)N进行球磨处理使其成为静磁易面γ’-Fe_(4)N粉体,所获得的易面粉体与聚氨酯(PU)混合制成软磁复合材料.与未球磨静磁易面化处理的非易面γ’-Fe_(4)N复合材料相比,静磁易面γ’-Fe_(4)N软磁复合材料具有更高的磁导率,更低的功率损耗.与同类软磁复合材料相比,通过氮化工艺降低磁性铁颗粒内涡流效应,静磁易面γ’-Fe_(4)N软磁复合材料具有优异的高频软磁性能.静磁易面γ’-Fe_(4)N为软磁复合材料匹配第3代宽禁带半导体的高频应用提供了一种新思路.

Soft magnetic composite materials are prepared by mixing magnetic materials and insulating materials,which possess both the excellent magnetism of magnetic materials and the low resistivity of insulating materials.They possess broad application prospects in emerging power electronics industries such as photovoltaic inverters,new energy vehicles,and charging stations.The third-generation high-frequency wide bandgap semiconductors,mainly composed of SiC and GaN,have the operating frequency of soft magnetic materials raised to MHz.However,current soft magnetic materials have significant core losses at high frequencies.Therefore,people are focus their attention on developing new soft magnetic composite materials to reduce iron core losses at high frequencies.In this paper,g'-Fe_(4)N with high resistivity is prepared by nitriding carbonyl iron powders,showing its excellent soft magnetic properties,and the g'-Fe_(4)N is ball-milled to become easy plane g'-Fe_(4)N powder.Compared with the none easy plane g'-Fe_(4)N powders,the none easy plane g'-Fe_(4)N powders are spherical in shape,the easy plane g'-Fe_(4)N powders exhibit a high aspect to thickness ratio in sheet shape.The obtained easy plane powders are mixed with polyurethane insulation to make the soft magnetic composite.There is a significant difference between the in-plane and out-of-plane hysteresis loop of the magnetostatic easy plane g'-Fe_(4)N soft magnetic composite,and the in-plane hysteresis loop is more easily magnetized to saturation state.The degree of plane orientation is 98.46%.The fitting analysis results of the Jiles-Atherton model also prove its easy plane characteristic,and has higher effective permeability and lower power loss than the counterparts of the none easy plane g'-Fe_(4)N composite that is not ball-milled.After loss separation,it is found that in a low frequency range,hysteresis loss is the main loss,while in a high frequency range,the excess loss will surpass the hysteresis loss,acting as the main loss,the magnetostatic easy plane g'-Fe_(4)N soft magnetic composites material reduces hysteresis loss and excess loss.Comparing with similar soft magnetic composites,the eddy current effect in magnetic iron particles is reduced by nitriding process,and the magnetostatic easy plane g'-Fe_(4)N soft magnetic composite has excellent high-frequency soft magnetic properties.Magnetostatic easy plane g'-Fe_(4)N provides a new idea for the high-frequency application of soft magnetic composites matching the third generation wide bandgap semiconductors.