Heating rate dependence of coercivity and microstructure of Fe–B–P–Cu nanocrystalline soft magnetic materials
Heating rate dependence of coercivity and microstructure of Fe–B–P–Cu nanocrystalline soft magnetic materials
复制标题
DOI：
10.1016/j.jallcom.2020.157832
复制
发表时间：
2020-11
影响因子：
6.2
通讯作者：
Y. Nomura;Jun Uzuhashi;Tatsuya Tomita;Toru Takahashi;H. Kuwata;T. Abe;T. Ohkubo;K. Hono
中科院分区：
文献类型：
--
作者：
Y. Nomura;Jun Uzuhashi;Tatsuya Tomita;Toru Takahashi;H. Kuwata;T. Abe;T. Ohkubo;K. Hono
Fe-B-P-Cu带的纳米晶结构和软磁性能受非晶前驱体结晶加热速率的影响较大。采用透射电子显微镜（TEM）和原子探针断层扫描（APT）研究了Fe84.8B4.9P9.5Cu0.8（富p）和Fe84.8B10.9P3.5Cu0.8（富b）熔融纺丝带在0.67 K/s和6.7 K/s两种不同加热速率下结晶的结构和软磁性能。与升温速率无关，富p带的矫顽力较小，而富b带的矫顽力与升温速率关系较大。APT分析表明，富p纳米晶带中的Cu团簇尺寸大于富b纳米晶带中的Cu团簇，而它们的数量密度几乎相同。同时，高升温速率导致两种样品中的Cu团簇尺寸更大，Cu浓度更高，这表明只有当Cu团簇大于临界尺寸时，它们才能有效地作为α-Fe的核。APT分析确定的α-Fe与残余非晶相的溶质分配行为与计算得到的Fe-P-B三元相图中α-Fe与液相的联结线一致。P在非晶/α-Fe界面析出，表明晶化过程中P在非晶相中的体积扩散控制了晶粒的生长。
The nanocrystalline structure and soft magnetic properties of melt-spun Fe–B–P–Cu ribbons are largely influenced by heating rates for crystallization of amorphous precursors. In this study, we investigated the structure and soft magnetic properties of Fe84.8B4.9P9.5Cu0.8(P-rich) and Fe84.8B10.9P3.5Cu0.8(B-rich) melt-spun ribbons crystallized at two different heating rates, 0.67 K/s and 6.7 K/s, using transmission electron microscopy (TEM) and atom probe tomography (APT). The P-rich ribbon shows smaller coercivity regardless of the heating rates, while the B-rich ribbon shows large heating rate dependence of the coercivity. APT analyses have revealed that the size of Cu clusters in the P-rich nanocrystalline ribbon is larger than that in the B-rich nanocrystalline ribbon while their number densities are nearly the same. Also, the high heating rate led to a larger size and higher Cu concentration of the Cu clusters in both samples, indicating that the Cu clusters are effective as nuclei for α-Fe only when they are larger than a critical size. The solute partitioning behaviors between α-Fe and residual amorphous phase determined by APT analyses are consistent with the tie-lines between α-Fe and liquid phase in a calculated Fe–P–B ternary phase diagram. P was found to segregate at amorphous/α-Fe interface, suggesting the grain growth is controlled by the volume diffusion of P in the amorphous phase during their crystallization process.