为提高纳米晶软磁合金的高频磁性能，本工作研究了带材厚度(15~23 μm)对Fe_75.2Si₁₃B₈Cu₁Nb_2.8纳米晶软磁合金的组织结构及静态和高频磁性能的影响规律，并通过磁畴结构表征分析了带材厚度对其高频磁化行为的影响机制。结果表明，不同厚度的快淬合金带材均呈现非晶态，843 K退火60 min后，形成相似的非晶+ α-Fe纳米晶双相组织，α-Fe的平均晶粒尺寸为11.0~11.6 nm。所有纳米晶合金带材的饱和磁通密度和矫顽力无明显差异，分别为1.35~1.36 T和0.5~0.6 A/m。纳米晶合金的高频软磁性能随带材厚度的减小而逐渐提升，薄带材的有效磁导率(μ_e)可在更高频率下保持稳定，且随频率增加的衰减较慢。15 μm厚度带材在100 kHz和1 MHz下的μ_e分别为17000和5200，远高于23 μm厚带材的14000和2900。减小带材厚度能显著降低单位质量铁心损耗(P_cm)，在0.2 T、100 kHz和0.2 T、500 kHz条件下，15 μm厚带材的P_cm分别为67和811 W/kg，较23 μm厚带材分别降低38.0%和41.9%。损耗分离结果表明，薄带材较低的P_cm主要归因于涡流损耗和剩余损耗的降低。减小带材厚度可细化纳米晶合金的磁畴，有助于高频下磁畴旋转，从而提高高频磁导率、降低剩余损耗。

The development of third-generation semiconductors has increased power density in electronic devices while increasing demands for high-frequency performance of internal soft magnetic materials. Fe-based nanocrystalline alloys are among the most promising candidates for high-frequency applications owing to their excellent comprehensive soft magnetic properties, including high saturation magnetic flux density (B_s), high permeability, and low core loss per unit mass (P_cm). However, further improvements in their high-frequency properties are required. This study prepared Fe_75.2Si₁₃B₈Cu₁Nb_2.8 nanocrystalline alloy ribbons with 15-23 μm thicknesses by adjusting the Cu wheel speed. The effects of ribbon thickness on the structure and static/high-frequency magnetic properties of the nanocrystalline alloys were investigated. Furthermore, the high-frequency magnetization mechanisms of nanocrystalline alloys with varying ribbon thicknesses were examined through magnetic domain structure characterization. Results indicate that all as-spun alloy ribbons exhibit an amorphous structure and transform into a similar amorphous + α-Fe nanocrystalline dual-phase structure after annealing at 843 K for 60 min, with average α-Fe grain sizes of 11.0-11.6 nm. The static magnetic properties of all ribbons are nearly identical, with B_s and coercivities of 1.35-1.36 T and 0.5-0.6 A/m, respectively. On the contrary, the high-frequency soft magnetic properties improve with decreasing ribbon thickness. The effective permeability (μ_e) of thinner ribbons remains stable and exhibits milder attenuation with increasing frequency. At 100 kHz and 1 MHz, the 15-μm ribbon has μ_e of 17000 and 5200, respectively, which are substantially higher than the values of 14000 and 2900 for the 23-μm ribbon. Moreover, the thinner ribbons demonstrate reduced P_cm. At 0.2 T, 100 kHz and 0.2 T, 500 kHz, the 15-μm ribbon shows P_cm of 67 and 811 W/kg, representing reductions of 38.0% and 41.9%, respectively, compared with the 23-μm ribbon. Loss separation analysis indicates that the reduced P_cm of the thin ribbon is primarily attributed to decreased eddy current loss and residual loss. The decreased ribbon thickness refines the magnetic domains, facilitating domain rotation at high frequencies and improving high-frequency permeability while reducing residual loss.