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This work could have implications with regard to the mechanism of hydrogen decrepitation of sintered NdFeB magnets during the well-established recycling process described by Walton et al. [19] and [20]. During this process, scrap sintered NdFeB magnets are damaged in air to expose a clean surface suitable for hydrogen decrepitation. …Nov 1, 2017 · Fig. 1. Illustration of the Hydrogen Decrepitation Press-Less Process (HD-PLP) recycling of anisotropic sintered NdFeB magnet. Passivated commercial N48M sintered magnets were used as starting material and hydrogen was applied to disintegrate the magnets inside a ball milling container. The hydride powder was both used directly and some powder ... The decrepitation process and related changes in the sample temperature are analysed to explain the experimentally observed weight gain curve of a Nd–Fe–B sample due to hydrogen uptake. It is shown that the expansion of the specific surface resulting from decrepitation of the sample is the most important parameter controlling …H 2 can be used to extract NdFeB magnets from the automotive scrap, however, many challenges in the recycling are presented.. The importance of design choices, having negative impact on the recycling, are investigated in this work, so can be avoided. • Higher Dy additions slow down the kinetics of the hydrogen decrepitation …magnets. The thermal and mechanical impact of the hydrogen decrepitation process was assessed during hydrogen processing. For all forms of sintered NdFeB scrap the surface condition of the magnets is important as oxidation has been shown to inhibit the onset of the hydrogen decrepitation process. In this Dec 25, 2017 · Recycling of Nd-Fe-B magnets is one of the few solutions to alleviate the supply risks of certain rare earth elements (REE) such as Nd and Dy. One of the most promising solutions with regards to extraction of end-of-life (EOL) magnets is to apply hydrogen decrepitation and to physically separate the Nd-Fe-B as a demagnetized hydrogenated powder. For the second type, three popular techniques, hydrogen decrepitation (HD), HDDR, and MS are applied to produce magnetic powders with the waste magnets. Note that the resultant powders prepared from the three techniques are single crystal powders, textured polycrystalline powders, and random aligned polycrystalline powders, respectively. ...Sagawa obtained ultrafine NdFeB grain by innovative HD (hydrogen-decrepitation) + HDDR (hydrogenation-disproportionation-desorption-recombination) + helium jet milling process. It should be noted that the helium gas is more suitable than nitrogen gas to fabricate ultrafine powder due to its lighter mass fraction, and will also …The corrosion and degradation of sintered Nd–Fe–B type magnets by hydrogen obtained from moisture in the environment has been termed the Negative Harris Effect. The residual hydrogen from the hydrogen decrepitation process in the manufacture of fully dense magnets is desorbed completely during the vacuum sintering …calcium [12] and hydrogen decrepitation [1,13-19]. Many of these are under current development. Hydrogen decrepitation (HD) is based on the selective synthesis of neodymium hydrides though the reaction of hydrogen gas with neodymium located in the Nd-Fe-B magnet. HD process was originally designed and patented by Harris et al. (1979) as a way to In this paper it is demonstrated that hydrogen could play a vital role in this process. Fully dense sintered NdFeB-type magnets have been subjected to the …Hydrogen Decrepitation and Recycling of NdFeB-type Sintered Magnets. Miha Zakotnik, E. Devlin, +1 author. A. Williams. Published 2006. Materials Science, Engineering. Journal of Iron and Steel Research International. View via Publisher. Save to Library.Received 21st February 2020, Accepted 5th March 2020. meric portion. The PA-free magnet powder was found to retain >90% of its original magnetic properties. Two epoxy-bonded magnets produced with this recycled magnet powder showed magnetic properties. DOI: 10.1039/d0gc00647e. The fabrication of Nd-Fe-B sintered magnets is composed of quite a few processes mainly including strip casting, hydrogen decrepitation, jet-milling, magnetic alignment and pressing, sintering and subsequent heat treatment, machining, and surface coating. ... Possible methods of recycling NdFeB-type sintered magnets using the …Abstract. In this paper we describe and discuss the use of hydrogen in the processing ofNdFeB-type magnets. The roles of hydrogen in the hydrogen decrepitation (HD) and hydrogenation, disproportionation, desorption and recombination (HDDR) processes are considered together with the characteristics of the magnets produced by …The intrinsic magnetic coercivity (H ci) of Nd‐Fe‐B‐based permanent magnet material is profoundly affected by hydrogen absorbed during the hydrogen decrepitation (HD) process for producing anisotropic powders from bulk anisotropic hot‐deformed MAGNEQUENCH (MQ) magnets.Hydrogen (H) content and x‐ray diffraction …The hydrogen-absorbing NdFeB powder absorbs heat in the plasma and rapidly decomposes and dehydrogenates. At the same time, in the dehydrogenation process, the particles are cracked and broken to form fine NdFeB powder due to rapid heat absorption and release of a large amount of hydrogen, and the NdFeB powder is at a high …T D ACCEPTED MANUSCRIPT The Use of Hydrogen to Separate and Recycle Neodymium-Iron-Boron-type Magnets from Electronic Waste A. Walton a, Han Yi , N.A. Rowson b, J.D. Speight , V.S.J. Mann a, R.S. Sheridan , A. Bradshaw a, I.R. Harris a, A.J. Williams School of Metallurgy and Materials a and School of Chemical Engineering b, …Michihide Nakamura, Masashi Matsuura, Nobuki Tezuka, Satoshi Sugimoto, Yasuhiro Une, Hirokazu Kubo, Masato Sagawa; Preparation of ultrafine jet-milled powders for Nd-Fe-B sintered magnets using hydrogenation–disproportionation–desorption–recombination and hydrogen …(2020) Piotrowicz et al. Journal of Mining and Metallurgy, Section B: Metallurgy. Rare earth magnets based upon neodymium-iron-boron (NdFeB) are employed in many high tech applications, including hard disk drives (HDDs). The key elements in manufacturing NdFeB magnets are rare earth elements (REE... The HD-process converts the magnets possible to recover the hard magnetic powder from a to a powder due to the expansion of the material on particular device (e.g. hard disk drive or electric motor) hydrogen absorption. Recycling of NdFeB magnets by by simply exposing the complete system to a hydrogen this means has been proposed by Rivoirard ...calcium [12] and hydrogen decrepitation [1,13-19]. Many of these are under current development. Hydrogen decrepitation (HD) is based on the selective synthesis of …The initial step for manufacturing NdFeB plated permanent magnets in this unit process is NdFeB alloying and strip casting. NdFeB alloy is composed of 72% iron, 27% neodymium, and 1% boron from boron carbide (Sprecher et al., 2014). In order to stop free iron from forming, a small amount of iron formed between NdFeB crystals, the alloy is ...Jan 1, 2007 · The rapid cooling of the strip flakes suppresses the growth of soft α-Fe branch crystal grains. The thickness of the strip flakes was about 0.25–0.35 mm. Hydrogen decrepitation (HD), which uses the expansion of hydrogen to break up the flakes, was followed by milling in a jet mill (JM). The particles were then accelerated to supersonic ... Sep 7, 2022 · We report investigations on the processing by Spark Plasma Sintering (SPS) of RE2Fe14B (RE = Nd, Pr…) powders obtained by hydrogen decrepitation of decommissioned magnets and the magnetic properties of the consolidated magnets. First experiments have been carried out with a commercial powder to make clear the mechanisms occurring during the powder densification. The magnetic properties of ... This means that NdFeB magnets are prone to galvanic corrosion, in particular, intergranular corrosion attack. The corrosion mechanism as well as the hydrogen decrepitation behaviour of microcrystalline (i.e. sintered) magnets has been studied extensively [11], [12], [13], [14].The scrap sintered Nd–Fe–B magnets were recycled as the raw materials for bonded magnets using the hydrogen decrepitation (HD) process. The HD powders have the lowest oxygen and hydrogen content by hydrogenation at 150 °C with 1 bar H2 pressure and dehydrogenation at 600 °C. The powders with the largest particle size (>380 μm) …For the second type, three popular techniques, hydrogen decrepitation (HD), HDDR, and MS are applied to produce magnetic powders with the waste magnets. Note that the resultant powders prepared from the three techniques are single crystal powders, textured polycrystalline powders, and random aligned polycrystalline powders, respectively. ...Oct 25, 2015 · End-of-life NdFeB magnets are important secondary RE sources. Several recycling methods for NdFeB magnets have been developed, such as direct reuse,4 hydrogen decrepitation (HD) and regeneration of new NdFeB,5–7 pyrometallurgical methods,8,9 hydrometallurgical methods,10–13 gas-phase extraction. Received 21st February 2020, Accepted 5th March 2020. meric portion. The PA-free magnet powder was found to retain >90% of its original magnetic properties. Two epoxy-bonded magnets produced with this recycled magnet powder showed magnetic properties. DOI: 10.1039/d0gc00647e. Hydrogen decrepitation and recycling of NdFeB-type sintered magnets Zakotnik M, Devlin E, Harris IR, Williams AJ ... Environmental degradation of NdFeB magnets Yan GL, McGuiness PJ, Farr JPG, Harris IR Journal of Alloys and Compounds 2009;478:188-92 Oxidation of NdFeB-type magnets modified with additions of Co, Dy, Zr and V ...Electrolytic Hydrogen Decrepitation of NdFeB Magnets Under Ambient Conditions. V. Kaplan, Y. Feldman, …, I. Lubomirsky. Journal of Sustainable Metallurgy • Volume 8, Issue 3 • 1 September 2022. 1 citation; Scopus record. Article. 2D Pb-Halide Perovskites Can Self-Heal Photodamage Better than 3D Ones.Semantic Scholar extracted view of "Possible methods of recycling NdFeB-type sintered magnets using the HD/degassing process" by M. Zakotnik et al. ... The purpose of this thesis was to study the Hydrogen Decrepitation (HD) process as a way to recycle waste scraps of Nd-Fe-B sintered magnets into highly coercitive and anisotropic …Mar 1, 1985 · The hydrogen decrepitation (HD) process are studied in detail based on these results. The hydrogen absorption mechanism of Sm(CoFeCuZr) 7.6 alloy can be regarded as a hydrogen dissolution process without phase transformation. In addition, the existence of a large amount of fine grains in the SC has an adverse effect on the alignment, which can ... Unfortunately, the contained NdFeB magnets break up into a friable magnetized powder which then sticks to the ferrous scrap and the shredder itself. A production-scale plant in Germany planned to go onstream in 2024 and a pilot plant launched a few months ago in the UK, expected to graduate to production-scale in 2023, …Apr 15, 2022 · An effective and complete processing route for the recycling of sintered Nd-Fe-B scrap magnets was proposed. Sintered Nd-Fe-B magnets were subjected to the Hydrogen Decrepitation (HD) process at various temperatures in the range of 50–300 °C, at two different pressures, 50 kPa and 200 kPa, followed by vacuum dehydrogenation in the range of 720–820 °C. The hydrogen treatment of the Nd‐Fe‐B alloy ingots was found to produce magnet powders with good magnetic properties. Typical magnetic properties of these powders are as follows; 4πIs = 9.5 kG, Br = 7.7 kG, iHc = 9.4 kOe, and (BH)max = 12.2 MGOe. Microstructural studies of these powders showed that they are made of fine …hydrogen uptake (2043.76 μmol∙g-1) was received for conditions 4 bar and room temperature, while the lowest (925.27 μmol∙g -1 ) for 1 bar at 400 0 C (Figure 4). At room temperature (29Jan 1, 2020 · Hydrogen decrepitation (HD) can be used as a direct reuse approach and effective method of recycling process to turn solid sintered magnets into a demagnetised powder for further processing. calcium [12] and hydrogen decrepitation [1,13-19]. Many of these are under current development. Hydrogen decrepitation (HD) is based on the selective synthesis of …Sep 14, 2000 · This way of powdering known as hydrogen decrepitation (HD) is a well-established stage of manufacturing technologies of sintered [2], [3] and bonded [4] Nd–Fe–B magnets. The interstitial hydrogen in the ferromagnetic Nd 2 Fe 14 B phase reduces significantly its anisotropy field H A. That is why desorption of hydrogen is necessary in order ... Various efforts have been made in the past for direct recycling of spent NdFeB magnet using hydrogen decrepitation followed by resintering method (Zakotnik et al., 2009; Herraiz et al., 2016). In ...Sagawa obtained ultrafine NdFeB grain by innovative HD (hydrogen-decrepitation) + HDDR (hydrogenation-disproportionation-desorption-recombination) + helium jet milling process. It should be noted that the helium gas is more suitable than nitrogen gas to fabricate ultrafine powder due to its lighter mass fraction, and will also … In this paper, the hydrogen processing of scrap magnets has been demMay 5, 2017 · Typically, alloys are processed using the Hydr We ascribe the volume expansion during ATF aging to the incorporation of hydrogen dissociated from the organic liquid ATF into the melt-spun NdFeB powder. Hydrogen is known to diffuse into the Nd2Fe14B crystal structure [2–4] and occupy interstitial sites to form the isomorphic hydride Nd2Fe14BHx with up to x=5 H per formula …There are many major production steps –plus numerous sub steps- in the manufacture of high-quality, high-tech Neodymium magnets. Each step is highly important, and each step is an essential part of a highly refined … Jun 27, 2014 · The scrap sintered Nd–Fe–B magnets were recy Hydrogen Decrepitation is a process step used in the production of Neodymium magnets to create extremely small grains in the material. Neodymium magnets must have very small grains averaging about 5 micrometers in order to have the best magnetic properties. But the grain sizes after casting are much larger than that, so they must be ground down ... Hydrogen decrepitation as a highly efficient and excel...