High-performance rare-earth hard magnetic nanoparticles via the calciothermic reduction and chemoselective dissolution
- Authors
- Yun, Saemee; Koo, Kangmo; Lee, Jimin; Park, Ji Young; Jang, Byungkwon; Han, BoKyeong; Choa, Yong-Ho
- Issue Date
- Aug-2023
- Publisher
- Korean Society of Industrial Engineering Chemistry
- Keywords
- Calciothermic reduction; Magnetic properties; Nd2Fe14B; NH4NO3; Schlenk line
- Citation
- Journal of Industrial and Engineering Chemistry, v.124, pp.340 - 347
- Indexed
- SCIE
SCOPUS
KCI
- Journal Title
- Journal of Industrial and Engineering Chemistry
- Volume
- 124
- Start Page
- 340
- End Page
- 347
- URI
- https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/188323
- DOI
- 10.1016/j.jiec.2023.04.027
- ISSN
- 1226-086X
- Abstract
- Magnetic Nd2Fe14B nanoparticles are synthesized by a bottom-up process via calciothermic reduction, which complements the negative reduction potential of rare-earth elements, thus affording nanoscale products. However, to obtain high-purity, high-performance magnetic nanoparticles, residual calcium by-products that persist after calcium thermal reduction-diffusion must be selectively removed. In previously reported rinsing methods, H2O or H+ diffuse into the magnetic nanoparticles, thereby leading to hydridation. Herein, we propose a novel rinsing solution, NH4NO3/methanol, that does not deteriorate the magnetic properties. The magnetic properties are enhanced by selectively removing calcium by-products (i.e., CaO) from the magnetic nanoparticles with NH4NO3/methanol solution and by preventing hydridation and oxidation using zeolite and Schlenk line. The intrinsic coercivity (Hci) is maintained at 75.1 % (from 8.5 kOe to 6.3 kOe), and the saturation magnetization (Ms) increases two-fold (110.08 emu/g) after rinsing with NH4NO3 solution, compared with prior to rinsing treatment (47.363 emu/g). Rinsing the magnetic nanoparticles with NH4NO3/methanol solutions does not cause deterioration of the obtained Nd2Fe14B nanostructures, where Ms = 112.0 emu/g and Hci = 8.4 kOe after rinsing with NH4NO3/methanol using the zeolite and Schlenk line. Using rinsing methods in previous studies. 3.5 % of the initial coercivity is maintained, whereas with the new rinsing method, 95.2 % of the coercivity is maintained, thus indicating that rinsing does not induce deterioration of the magnetic properties. © 2023 The Korean Society of Industrial and Engineering Chemistry
- Files in This Item
-
Go to Link
- Appears in
Collections - ETC > 1. Journal Articles
![qrcode](https://api.qrserver.com/v1/create-qr-code/?size=55x55&data=https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/188323)
Items in ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.