Microstructure of Multistage Annealed Nanocrystalline SmCo₂Fe₂B Alloy with Enhanced Magnetic Properties

Journal Article · Sat Feb 01 00:00:00 EST 2014 · Journal of Applied Physics, 115(6):Article No. 063902

DOI:https://doi.org/10.1063/1.4865298· OSTI ID:1176832

Jiang, Xiujuan; Devaraj, Arun; Balamurugan, B.; Cui, Jun; Shield, Jeffrey E.

The microstructure and chemistry of SmCo₂Fe₂B melt-spun alloy after multistage annealing was investigated using high resolution transmission electron microscopy (HRTEM) and 3D atom probe tomography. The multistage annealing resulted in an increase in both the coercivity and magnetization. The presence of Sm(Co,Fe)₄B (1:4:1) and Sm₂(Co,Fe)₁₇B_x (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. The variations in the local chemistry after the secondary annealing were considered pivotal in improving the magnetic properties.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1176832
• Report Number(s): PNNL-SA-98806; 48200
• Journal Information: Journal of Applied Physics, 115(6):Article No. 063902, Journal Name: Journal of Applied Physics, 115(6):Article No. 063902
• Country of Publication: United States
• Language: English

Related Subjects

COERCIVE FORCE
THERMODYNAMIC PROPERTIES
X-RAY DIFFRACTION
SmCo
atom probe
multistage annealing
coercive force
magnetic annealing
microstructural properties
thermodynamic properties
x-ray diffraction
Environmental Molecular Sciences Laboratory