Improving soft magnetic properties in FINEMET-like alloys with Ga addition

• Published in: Journal of magnetism and magnetic materials 2019-10, Vol.487, p.165297, Article 165297
• Main Authors: Zhu, Qianke, Chen, Zhe, Zhang, Shuling, Li, Qiushu, Jiang, Yong, Wu, Peixuan, Zhang, Kewei
• Format: Article
• Language: English
• Subjects: Amorphous; Annealing; Coercivity; Crystallization; Ferrous alloys; Gallium; Grain size; Magnetic permeability; Magnetic properties; Magnetic saturation; Nanocrystalline; Nucleation; Nucleation sites; Silicon
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2019.165297

[Display omitted] •The FINEMET-like FeSiNbBCuGa ribbons were fabricated and their crystallization kinetics, magnetic properties and microstructure were investigated.•In the ribbon with 6 at.% Ga content, the Bs was higher than that of FINEMET alloy by 11.4 percent while the Hc stayed the same value.•The primary crystallization of ribbons was changed from α-Fe (Si) into α-Fe (Ga, Si) phase with the gradually substitution of Si by Ga.•The precipitation of Ga could depress the partition of Si into α-Fe phase, and thus the α-Fe (Ga, Si) phase with high Ga and low Si concentration could be obtained. The effect of partial substitution of Si by Ga on the microstructure and soft magnetic properties of FINEMET-like Fe73.5Si13.5−xNb3B9Cu1Gax (x = 0, 3, 6, 9, 12 at.%) alloys has been investigated. It was found that the primary crystallization of ribbons was gradually changed from α-Fe (Si) into α-Fe (Ga, Si) phase with the increase of Ga content. Besides, the Fe-Ga clusters were detected in the amorphous ribbon with x = 6, which could provide nucleation sites for the α-Fe (Ga, Si) phase. In such case, the crystallization temperature of the ribbons with Ga addition was lower than that of ribbon without Ga addition. For the ribbon with x = 6, the precipitation of Ga element was priority to that of Si, which leads to the ‘increase-decrease’ tendency for the changes of lattice parameter with the increase of annealing temperature. Meanwhile, compared to the α-Fe (Si) phase with enrichment of Si for x = 0 ribbon, the α-Fe (Ga, Si) phase with high Ga and low Si concentration for the x = 6 ribbon was obtained, together with fine grain size (11 nm) of α-Fe (Ga, Si) phase, resulting to the same low coercivity (0.24 A/m), higher saturation magnetization (1.37 T) and maximum permeability after annealed at 455 °C for 1 min.