Temperature Effects on Phase Evolution and Particle Morphology in Ce-Rich Commercial NdFeB Magnets During High-Pressure Hydrogen Decrepitation

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dc.authorid0000-0003-0848-767X
dc.authorid0000-0002-1526-803X
dc.authorid0009-0007-0738-2370
dc.authorid0000-0002-0826-7880
dc.contributor.authorBILGIN, Salih
dc.contributor.authorARIK, M. Nasuh
dc.contributor.authorSARITAS, Senem
dc.contributor.authorÇAKIR, Öznur
dc.date.accessioned2026-01-28T11:57:09Z
dc.date.available2026-01-28T11:57:09Z
dc.date.issued2026-01-14
dc.departmentTENMAK-Nadir Toprak Elementleri Araştırma Enstitüsü
dc.departmentTENMAK-Bor Araştırma Enstitüsü
dc.description.abstractNdFeB magnets are essential to clean energy and advanced technological applications due to their superior magnetic properties. However, the availability of rare earth elements is susceptible to geopolitical and environmental challenges. The recycling of NdFeB permanent magnets from secondary sources represents a strategic approach to mitigate this supply risks associated with critical raw materials, particularly Neodymium (Nd) and Dysprosium (Dy). Among the available recycling techniques, Hydrogen Decrepitation (HD) has demonstrated significant potential for the efficient recovery of these elements from commercial magnets. This study investigates the effect of temperature during high pressure hydrogen decrepitation on the structural, microstructural, and compositional evolution of a commercial NdFeB magnet with relatively high Ce content, which is confirmed by inductively coupled plasma (ICP-OES) analysis provided baseline compositional data for the starting material. Experiments were performed at 9 bar hydrogen pressure under constant conditions of time, with three processing temperatures investigated (25 °C, 50 °C, and 75 °C). Scanning electron microscopy (SEM) of the initial magnet illustrated Ce-rich phases, while X-ray diffraction (XRD) confirmed the presence of CeFe2. According to XRD results, main RE2Fe14B phase transformed RE2Fe14BHx hydride phase after hydrogenation process. However, the CeFe2 peaks disappeared, indicating amorph phase transformation. In addition to hydride phase and CeFe2 phase, the presence Nd2O3 phase was detected. LECO elemental analysis was performed to quantify the amount of the oxygen and hydrogen inside hydrogenated powders. These results confirm the presence of oxide and hydrides with different amount. The results demonstrated that powders processed at 75 °C retained higher oxygen levels compared to those treated at 25 °C and 50 °C. This behaviour is attributed to less efficient hydrogen desorption and increased surface oxidation caused by extensive fragmentation. Furthermore, higher processing temperatures produced more agglomerated morphologies with limited cracking, lowering surface reactivity. Overall, the study highlights the effect of temperature on particle morphology, particle fragmentation, and oxidation behaviour during HD. These insights provide valuable guidance for the optimization of NdFeB magnet recycling and reprocessing strategies.
dc.identifier.urihttps://kurumsalarsiv.tenmak.gov.tr/handle/20.500.12878/2092
dc.institutionauthorBILGIN, Salih
dc.institutionauthorARIK, M. Nasuh
dc.institutionauthorSARITAS, Senem
dc.institutionauthorÇAKIR, Öznur
dc.language.isoen
dc.publisherTurkish Energy, Nuclear and Mineral Research Agency (TENMAK)
dc.subjectNdFeB magnets
dc.subjecthydrogen decrepitation
dc.subjectrecycling
dc.titleTemperature Effects on Phase Evolution and Particle Morphology in Ce-Rich Commercial NdFeB Magnets During High-Pressure Hydrogen Decrepitation
dc.typeconferenceObject
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