| AVS 61st International Symposium & Exhibition | |
| Atom Probe Tomography Focus Topic | Thursday Sessions |
| Session AP+AS+MC+NS+SS-ThM |
| Session: | APT Analysis of Semiconductors, Magnetic and Oxide Materials |
| Presenter: | Xiujuan Jiang, Pacific Northwest National Laboratory |
| Authors: | X. Jiang, Pacific Northwest National Laboratory A. Devaraj, Pacific Northwest National Laboratory B. Balamurugan, University of Nebraska-Lincoln J. Cui, Pacific Northwest National Laboratory J. Shield, University of Nebraska-Lincoln |
| Correspondent: | Click to Email |
Permanent magnets have garnered great research interest for energy applications. The microstructure and chemistry of a permanent magnet candidate—SmCo2Fe2B melt-spun alloy—after multistage annealing was investigated using high resolution transmission electron microscopy (HRTEM) and atom probe tomography. The multistage annealing resulted in an increase in both the coercivity and magnetization as is desired for permanent magnets design. The presence of Sm(Co,Fe)4B (1:4:1) and Sm2(Co,Fe)17Bx (2:17:x) magnetic phases were confirmed using both techniques. Fe2B at a scale of ~ 5 nm was found by HRTEM precipitating within the 1:4:1 phase after the second-stage annealing. Ordering within the 2:17:x phase was directly identified both by the presence of antiphase boundaries observed by TEM and the interconnected isocomposition surface network found in 3D atom probe results in addition to radial distribution function analysis. These observed variations in the local chemistry after the secondary annealing were considered pivotal in improving the magnetic properties.