Microstructure evolution and soft magnetic properties of Fe-based nanocrystalline soft magnetic composites coated with lubricant

作者：Yang, Sheng; Xu, Jia^*; Tian, Mengyuan; Wang, Jian; Yang, Tiansheng; Li, Guanbiao; He, Yihai; Zeng, Meiqin^*; Liu, Xin^*

来源：ADVANCED POWDER TECHNOLOGY, 2023, 34(5): 104024.

DOI：10.1016/j.apt.2023.104024

• Nanocrystalline soft magnetic composites
• Lubricant
• Microstructure
• Loss separation
• Soft magnetic properties

Here, the influence of zinc stearate on the microstructure and soft magnetic properties of the Finemet nanocrystalline soft magnetic composites (NSMCs) was systematically investigated. The results demon-strate that the core loss (Pcv) decreases and the effective permeability (le) increases of the NSMCs with increasing zinc stearate from 0 wt% to 2.0 wt%, which can be attributed to the reduction of residual stress during compaction. Further increasing zinc stearate up to 3.0 wt%, the Pcv increases sharply, while the le shows a decreasing trend. It can be considered that the addition of excess lubricant decomposes to CO2 during annealing, which deteriorates the magnetic properties. After annealing at 560 degrees C, a thin hybrid layer of only about 53.6 nm containing iron phosphate, ZnO, and SiO2 is formed in the NSMCs with 2.0 wt% zinc stearate, which exhibits excellent soft magnetic properties such as low Pcv of 174 kW/m3 and high le of 66.7 at Bm = 0.1 T for 50 kHz. In addition, loss separation has been carried out and suggests that the addition of lubricant mainly affects hysteresis loss in the total energy loss of NSMCs.