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Fully dense, sintered NdFeB-type magnets have been subjected to the hydrogen decrepitation (HD) process. The resultant powder has been subsequently …A combination of hydrogen decrepitation (HD) and jet milling (JM) has been used to produce powder for the processing of permanent magnets. ... The procedure has proved to be very successful for both NdFeB (Neomax) alloys and the NdDyFeNbB high coercivity alloys. The magnets produced by the HD/JM process showed excellent …Jan 1, 2006 · 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 (HD) process. The resultant powder has been subsequently processed in one of two ways in order to produce permanent magnets. NdFeB magnets are used in wind turbines and hybrid electric vehicles and are instrumental in progression toward a low-carbon economy. Recycling rare-earth elements (REEs) from NdFeB magnet waste is an important step toward building a sustainable REE supply chain. In this study, we describe an electrochemical process to selectively extract REEs from NdFeB magnet waste at room temperature. First ...

NdFeB magnets are used in wind turbines and hybrid electric vehicles and are instrumental in progression toward a low-carbon economy. Recycling rare-earth elements (REEs) from NdFeB magnet waste is an important step toward building a sustainable REE supply chain. In this study, we describe an electrochemical process to selectively extract REEs from NdFeB magnet waste at room temperature. First ... Jan 1, 2006 · 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 (HD) process. The resultant powder has been subsequently processed in one of two ways in order to produce permanent magnets.

Semantic Scholar extracted view of "A study of the effects of the addition of various amounts of Cu to sintered NdFeB magnets" by O. Ragg et al. ... from an Nd/sub 17/-Fe/sub 76.5/-B/sub 5/-Cu/sub 1.5/ alloy by a two-step heat treatment at 1370 K and 870 K following hydrogen decrepitation (HD)-processing. …

May 5, 2023 · The first is the hydrogen decrepitation (HD) process, which is already used in the primary production of NdFeB magnets to convert the alloy into powder form before further comminution. 46 The second process, named HDDR, which consists of two different steps, namely hydrogenation–disproportionation (HD) and desorption–recombination (DR), was ... Abstract. Some fully dense, sintered NdFeB-type magnets (employed in VCM disc drives) have been subjected to a recycling process using the hydrogen decrepitation (HD) process. After a brief milling treatment, the powder was aligned, pressed and re-sintered and this procedure was repeated four times with a progressive fall in the density …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 (HD) process. 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 …

Anisotropic powder was prepared with precursor (NdDy)-(FeCoNbCu)-B sintered magnets by hydrogen decrepitation, desorption, and subsequent annealing treatment. The hydrogen desorption was performed in magnetic fields of 0, 1, 3, and 5 T. The orientation of tetragonal phase grains of the powder was evaluated from the …

Investigating the properties of recycled NdFeB magnets. We report investigations on the processing by Spark Plasma Sintering (SPS) of RE Fe B (RE Abstract 2 14 = Nd, Pr. . . ) powders obtained by hydrogen decrepitation of decommissioned magnets and the magnetic properties of the consolidated magnets.

Anisotropic powder was prepared with precursor (NdDy)-(FeCoNbCu)-B sintered magnets by hydrogen decrepitation, desorption, and subsequent annealing treatment. The hydrogen desorption was performed in magnetic fields of 0, 1, 3, and 5 T. The orientation of tetragonal phase grains of the powder was evaluated from the …The basic compound for most Neodymium magnets is Nd2Fe14B. In practice, the actual chemical reaction used can be more complicated. A commonly used reaction is: 57 Fe + 8 B + 10 Fe2O3 + 7.5 Nd2O3 ...NdFeB permanent magnets have different life cycles, depending on the applications: from as short as 2–3 years in consumer electronics to 20–30 years in wind turbines. The size of the magnets ranges from less than 1 g in small consumer electronics to about 1 kg in electric vehicles (EVs) and hybrid and electric vehicles (HEVs), and can be …Due to the high strength and very compact structure of sintered NdFeB magnets, hydrogen decrepitation is a necessary step to break down the magnet mass. On the other hand, the resin-bonded NdFeB magnets have very low strength and can be easily crushed by heating and removing the resin and epoxy used in their fabrication. 39. 3.During the hydrogenation process, a volume expansion takes place, which promotes the formation of transgranular and intergranular cracks, causing the breakup of the material [29].Fig. 1 shows the different types of fracture that can occur during the hydrogen decrepitation process. The hydrogenation of the grain boundary phase can lead to an …Aug 4, 2022 · Here, we describe a room temperature, electrolytic decrepitation process applied to sintered Nd 2 Fe 14 B magnet fragments taken from end-of-life computer hard disk drives. In this process, fine grain, Nd-magnet-hydride powder is rapidly produced by atomic hydrogen in a 2 M KOH electrolyte.

NdFeB ingot exposed to hydrogen atmosphere due to the changes of hydride lattice parameters cracks. The process called HDDR (Hydrogenation - Decrepitation -D...Hydrogen is already used to process cast NdFeB in the Hydrogen Decrepitation (HD) process. The HD process is used extensively to reduce bulk (or strip) cast NdFeB ingots to friable, hydrogenated NdFeB granules/powder, prior to the production of jet milled powder which is then aligned, compressed and sintered to form fully dense …The high- and standard-grade material can be processed using either an HD/HDDR process or a sintering process, both of which are being tested in the course of this project. HD/HDDR stands for hydrogen decrepitation (HD) and hydrogen-disproportionation decomposition-recombination (HDDR). The HD/HDDR pulverised …May 11, 2020 · Metallurgical simulation and evaluation of the resource efficiency of whole production processes are of key importance for sound environmental impact assessments. Exergy dissipation analysis is suitable to quantify the theoretical limits of a process and pinpoint hotspots for improvements along the value chain. Production of NdFeB permanent magnets is evaluated herein using a simulation-based ... 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, are using the hydrogen-enabled process in efforts to commercialize it. At the center of both efforts is HyProMag Limited, closely tied to the University of Birmingham and an ...

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 The basic compound for most Neodymium magnets is Nd2Fe14B. In practice, the actual chemical reaction used can be more complicated. A commonly used reaction is: 57 Fe + 8 B + 10 Fe2O3 + 7.5 Nd2O3 ...

Step 3: Hydrogen Decrepitation. Rare earth elements have hydrogen absorption effect. NdFeB magnet alloy sheets are placed in a vacuum tube rotary furnace. As hydrogen gas is filled, rare earth-rich phase in the grain boundary of NdFeB magnet alloy absorbs hydrogen gas. After hydrogen absorption saturated, the rare earth-rich phase turns to ...big drive towards recycling of NdFeB magnets due to supply constraints for rare earth metals. Workers at the University of Birmingham have previously shown that hydrogen …Jun 27, 2014 · 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) bear the best magnetic properties (B r = 110.59 emu/g, H cj ... The ultrafine magnet waste (particle size < 1 µm) contained around 50% rare earths mainly in the form of hydroxides as they are generated from the hydrogen decrepitation. The major phases in ultrafine NdFeB waste were Nd(OH) 3, Fe 2 O 3 and Fe phases. When ultrafine magnet waste was leached with hydrofluoric acid, all the iron …The behavior of hydrogen absorption in the NdFeB Hydrogen Decrepitation process is affected by the shape of the NdFeB alloy, pressure and temperature curves of the reaction process, which makes the reaction process with characteristics of nonlinear, time-varying parameters and coupling. In this study, we proposed a state space modeling method to …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 ...Broadening the knowledge about the hydrogen decrepitation of the NdFeB type materials is needed to better service the process e.g. for recycling (at room temperature only 4 out of 10 scrap magnets undergo decrepitation which is likely to be the result of the number and character of pin holes in the electroplated coatings and/or to possible ...In this paper, the hydrogen processing of scrap magnets has been demonstrated as an extraction method for NdFeB from automotive rotors for the first time, with the aim to …

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 (HD)/hydrogenation disproportionation desorption recombination (HDDR) is a process used in manufacturing REPM and carried out as pretreatment before green body sintering. During hydrogenation, the Nd-rich grain boundary phase in NdFeB magnets initially absorbs hydrogen forming Nd hydride: [ 49 ].

The high- and standard-grade material can be processed using either an HD/HDDR process or a sintering process, both of which are being tested in the course of this project. HD/HDDR stands for hydrogen decrepitation (HD) and hydrogen-disproportionation decomposition-recombination (HDDR). The HD/HDDR pulverised …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 desorption of hydrogen from NdFeB powder and unmilled material produced using hydrogen decrepitation as a premilling technique was investigated using a mass spectrometer to monitor the hydrogen partial pressure in the system as the sample was heated under vacuum from room temperature to approximately 1000 degrees C. A …Hydrogen decrepitation (HD) is an effective and environmentally friendly technique for recycling of neodymium-iron-boron (NdFeB) magnets. During the HD process, the NdFeB breaks down into a matrix phase (Nd2Fe14BHx) and RE-rich grain boundary phase. The grain boundary phase in the HD powder is <2 μm in size. Recycled NdFeB material has …Jun 27, 2014 · 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) bear the best magnetic properties (B r = 110.59 emu/g, H cj ... Hydrogen decrepitation (HD) of Nd-Fe-B cast alloys is widely used in the processing of sintered magnets. The oxidation resistance under air of alloy powder …Various anti-corrosion coatings used on commercially available NdFeB-type magnets were comparatively examined for their durability and suitability for magnet reprocessing by hydrogen-assisted recycling (HPMS). Layer thickness and structure were determined by systematic microstructural analysis, and a standardized corrosion test …In this paper, the hydrogen processing of scrap magnets has been demonstrated as an extraction method for NdFeB from automotive rotors for the first time, with the aim to …Jul 1, 2002 · The effective diffusivity of hydrogen in NdFeB magnets is reduced with Co and Ga additions and as a result of the texture induced in the microstructure via die-upsetting process. In addition to the results shown in Fig. 8 , the thermal desorption behaviour related to the hydrogenation of a die-upset MQU-G magnet is different for the two ... Hydrogen decrepitation (HD) process and re-sintering NdFeB magnet scrap recycling by processing it in hydrogen, then milling, aligning, pressing and re-sintering it [38–40] Although different methods for NdFeB magnet recycling have been reported in the literature, only one piece of technology has been applied in practice by the Urban MiningOct 1, 2013 · The behavior of hydrogen absorption in the NdFeB Hydrogen Decrepitation process is affected by the shape of the NdFeB alloy, pressure and temperature curves of the reaction process, which makes the reaction process with characteristics of nonlinear, time-varying parameters and coupling. In this study, we proposed a state space modeling method to describe the dynamic mechanism model of the ... The method combines hydrogen decrepitation (HD) disintegration of the initial magnet, powder sieving and the Press-Less Process (PLP), where hydride powder is sintered in a …

big drive towards recycling of NdFeB magnets due to supply constraints for rare earth metals. Workers at the University of Birmingham have previously shown that hydrogen …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 …This paper studied the corrosion behavior of c ∥ and c ⊥ surfaces in sintered (Ce 0.15 Nd 0.85) 30 Fe bal B magnets. The conclusions are as follows: (1) The distribution of RE-rich phase is improved after Ce substitution compared with the sintered Nd-Fe-B magnets, and the value of A0 / A1 is approximate for both c ∥ and c ⊥ surfaces.Instagram:https://instagram. the listenerfc2ppv 3264420opercent27reillypercent27s choctawmanana como va a estar el clima The application of hydrogen decrepitation (HD) as a process for recycling Nd-Fe-B sintered magnets was reported in [ 6 ], in which the essential role of hydrogen in the recycling process was demonstrated. The obtained magnetic properties of the recycled magnet were ( BH) max = 290 kJ/m 3 (±5 kJ/m 3 ), Br = 1240 mT (±50 mT) and jHc = …It should be noted that hydrogen already plays a vital role in the production of sintered NdFeB-type magnets [1].The bulk alloy absorbs around 0.4 wt.% of hydrogen during the initial decrepitation stage and this hydrogen is desorbed during the subsequent vacuum sintering.Every tonne of alloy produces around 40 cubic meters of hydrogen … tammypercent27s pizzaconseitnsfw dva gets expelled The hydrogen decrepitation (HD) process for cast NdFeB alloys [1] has also been shown to be a technically and economically effective method for breaking down scrap sintered NdFeB magnets into a powder [2] and hence, for instance, for the separation of NdFeB-based magnets from end-of-life hard disk drive assemblies [3], [4].Hydrogen decrepitation (HD) is an effective and environmentally friendly technique for recycling of neodymium-iron-boron (NdFeB) magnets. During the HD process, the … proxy 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. …Mar 1, 2019 · Fig. 1 shows the hydrogen decrepitation curves of Nd-Fe-B SC and SM at 288 K with different initial hydrogen pressure. Under the initial hydrogen pressure of 0.1–1 Mpa, the HD process composes of four stages of magnets surface activation, slow hydrogenation of Nd-rich grain boundary phase, quick hydrogenation of Nd 2 Fe 14 B main phase grains, and slow hydrogenation of inner part of the magnets.