Enhanced coercivity in SmCo5 magnet subjected to hydrogen treatment

• Published in: Journal of alloys and compounds 2021-06, Vol.866, p.158272, Article 158272
• Main Authors: Bulyk, I.I., Chabanenko, V.V., Nabiałek, A., Zajarniuk, T., Szewczyk, A., Puźniak, R., Burkhovetskyi, V.V., Tarenkov, V.Yu, Wróbel, J., Borukh, I.V.
• Format: Article
• Language: English
• Subjects: Coercivity; Disproportionation; Grain refinement; Heating; Hydrogen treatment; Hysteresis loops; Magnetic properties; Microstructure; Permanent magnets; Samarium base alloys; Sm–Co alloys; Texture
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.158272

•Coercivity of the SmCo5 magnets, μ0Hc≤ 4.97 T.•Impact of HDDR on the properties.•Nanostructure of the sintered magnets. The relations between the phase recombination conditions and phase content, microstructure, and magnetic properties of sintered SmCo5-based permanent magnets, subjected to hydrogen treatment, were studied by X-ray diffraction, scanning electron microscopy, and magnetic hysteresis loop measurements. Recombination of the disproportionation products, SmH2±x, Co, and remains of SmCo5 phase, was carried out by heating the alloy in a vacuum to 850 °C with and without holding it for 1 h, and by heating it to 950 °С. It was shown that after recombination, the coercivity of the magnet, μ0Hc, reached the value of 4.90–4.97 T. The remnant magnetization increased from 27.7 to 43.5, and to 46.7 Am2/kg with increasing holding time during recombination from 0 to 1 h at a temperature of 850 °С, and with increased recombination temperature to 950 °C. The hysteresis loop rectangularity changed from 77 to 74.6, and to 78.8% under the same conditions.