{"title":"Recycling of additively printed anisotropic Nd-Fe-B bonded magnets","authors":"","doi":"10.1016/j.jmmm.2024.172360","DOIUrl":null,"url":null,"abstract":"<div><p>A high potential cost-effective and environmentally friendly method has been applied for recycling anisotropic Nd-Fe-B bonded magnets. Waste additively printed Hydrogenation-Disproportionation-Desorption-Recombination (HDDR) Nd-Fe-B anisotropic bonded magnet was pulverized into composite powder containing Nd-Fe-B particles and nylon binder through cryomilling at a liquid nitrogen temperature (∼77 K) under Ar inert atmosphere. Then, the cryomilled composite powder was warm compacted into a bonded magnet. The magnetic particles were aligned during post-compaction annealing under a magnetic field of 30 kOe. The recycled bonded magnets have a higher density (3 % enhancement), but slightly inferior magnetic properties compared to the original magnets, i.e., the magnetic remanence, coercivity and maximum energy product are reduced by 2 %, 3 % and 8 %, respectively. The scanning electron microscopy revealed that some HDDR Nd-Fe-B powder crumbled into fine particles during cryomilling. Powder X-ray diffraction showed a small amount of Nd-oxide impurity in the cryomilled powder. The slightly deteriorated magnetic properties are ascribed to the oxidation of Nd-Fe-B particles due to formation of fresh fracture surface during cryomilling. The approach enables the direct reuse of end-of-life bonded magnets in an economical and environmentally friendly way.</p></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Magnetism and Magnetic Materials","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0304885324006516","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
A high potential cost-effective and environmentally friendly method has been applied for recycling anisotropic Nd-Fe-B bonded magnets. Waste additively printed Hydrogenation-Disproportionation-Desorption-Recombination (HDDR) Nd-Fe-B anisotropic bonded magnet was pulverized into composite powder containing Nd-Fe-B particles and nylon binder through cryomilling at a liquid nitrogen temperature (∼77 K) under Ar inert atmosphere. Then, the cryomilled composite powder was warm compacted into a bonded magnet. The magnetic particles were aligned during post-compaction annealing under a magnetic field of 30 kOe. The recycled bonded magnets have a higher density (3 % enhancement), but slightly inferior magnetic properties compared to the original magnets, i.e., the magnetic remanence, coercivity and maximum energy product are reduced by 2 %, 3 % and 8 %, respectively. The scanning electron microscopy revealed that some HDDR Nd-Fe-B powder crumbled into fine particles during cryomilling. Powder X-ray diffraction showed a small amount of Nd-oxide impurity in the cryomilled powder. The slightly deteriorated magnetic properties are ascribed to the oxidation of Nd-Fe-B particles due to formation of fresh fracture surface during cryomilling. The approach enables the direct reuse of end-of-life bonded magnets in an economical and environmentally friendly way.
期刊介绍：
The Journal of Magnetism and Magnetic Materials provides an important forum for the disclosure and discussion of original contributions covering the whole spectrum of topics, from basic magnetism to the technology and applications of magnetic materials. The journal encourages greater interaction between the basic and applied sub-disciplines of magnetism with comprehensive review articles, in addition to full-length contributions. In addition, other categories of contributions are welcome, including Critical Focused issues, Current Perspectives and Outreach to the General Public.
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Technically original research documents that report results of value to the communities that comprise the journal audience. The link between chemical, structural and microstructural properties on the one hand and magnetic properties on the other hand are encouraged.
In addition to general topics covering all areas of magnetism and magnetic materials, the full-length articles also include three sub-sections, focusing on Nanomagnetism, Spintronics and Applications.
The sub-section on Nanomagnetism contains articles on magnetic nanoparticles, nanowires, thin films, 2D materials and other nanoscale magnetic materials and their applications.
The sub-section on Spintronics contains articles on magnetoresistance, magnetoimpedance, magneto-optical phenomena, Micro-Electro-Mechanical Systems (MEMS), and other topics related to spin current control and magneto-transport phenomena. The sub-section on Applications display papers that focus on applications of magnetic materials. The applications need to show a connection to magnetism.
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Review articles organize, clarify, and summarize existing major works in the areas covered by the Journal and provide comprehensive citations to the full spectrum of relevant literature.
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