Effects of Si addition on crystallization process and soft magnetic properties of high-Fe and high-Cu-content Fe–Si–B–P–Cu nanocrystalline alloys

• Published in: Journal of materials research and technology Vol. 30; pp. 5905 - 5915
• Main Authors: Xie, Lei, Li, Qiang, Chang, Chuntao, Fan, Xueru, He, Aina, Cai, Yuanfei, Chi, Qiang, Zhang, Guan, Dong, Yaqiang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2024; Elsevier
• Subjects: Crystallization behavior; Fe-based nanocrystalline alloys with high Fe and Cu contents; Si addition; Soft magnetic properties; Thermal stability; Si addition; Soft magnetic properties; Fe-based nanocrystalline alloys with high Fe and Cu contents; Crystallization behavior; Thermal stability
• ISSN: 2238-7854
• DOI: 10.1016/j.jmrt.2024.05.014

In this study, the effects of Si content on the glass-forming ability (GFA), thermal stability, annealing window, nanocrystallization process, and soft magnetic properties (SMPs) of Fe86.3-xSixB10P2Cu1.7 (x = 0, 1, 2, 3, and 4, denoted as Si0, Si1, Si2, Si3, and Si4, respectively) alloys with high Fe and Cu contents were investigated. Moderate addition of Si (x = 1, 2, and 3) enhanced the GFA and suppressed the precipitation of compound phases, thus leading to a large crystallization temperature interval (ΔTx) exceeding 185 °C for the alloys. Appropriate addition of Si also resulted in the formation of high-density and fine pre-existing α-Fe nanocrystals in as-spun ribbons and a high growth active energy of α-Fe crystals during the subsequent nanocrystallization process for the Si1, Si2, and Si3 alloys, enhancing competitive growth between α-Fe crystals and resulting in fine nanostructure and excellent SMPs of the nanocrystalline alloys (NAs). As a result, the Si1, Si2, and Si3 NAs obtained by annealing at 420 °C for 30 min exhibited excellent SMPs with saturation magnetic flux density (Bs) up to 1.84 T and a low coercivity (Hc) of approximately 10 A/m. In addition, statistical analysis of the relationship between the average grain size (D) of α-Fe crystals and Hc values of the NAs indicated that an Hc α D3 dependence is observed when the D is less than approximately 30 nm, while this dependence follows the well-known Hc α D6 relationship when the D is above 30 nm. The dependency relationship between D and Hc of NAs can guide the selection of an appropriate annealing process to optimize their SMPs.