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The oxidation kinetics in air of a commercial NdFeB magnet have been investigated over the temperature range 335–500°C. The oxide microstructure has been characterized by SEM, XRD and cross-sectional TEM. The results show that the external scale formed consists of an outer layer of Fe2O3 and an inner layer of Fe3O4 but that the principal degradation …Jan 1, 1991 · The subject of this paper is method (4) together with other aspects of the use of hydrogen in the processing of NdFeB-type magnets. 2. The hydrogen decrepitation process The manufacture of rare earth-transition metal magnets by the HD route was first proposed in a 1978 patent by Harris et al. [7]. Rare earth magnets based upon neodymium-iron-boron (NdFeB) are employed in many high tech applications, including h... Skip to main content. Sign In Create account . Journal Article OPEN ACCESS. THE USE OF THERMAL HYDROGEN DECREPITATION TO RECYCLE Nd-Fe-B MAGNETS FROM ELECTRONIC WASTE. Piotrowicz A; Pietrzyk S; …Sprecher, et al. [8] compared the environmental impact of producing virgin NdFeB magnets to producing recycled NdFeB magnets from waste computer hard disk drives (HDDs) using hydrogen decrepitation. The results showed that recycling in general was more favorable to the environment, and this was especially true for manual …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 (HD) is an effective and environmentally friendly technique for recycling of neodymium-iron-boron (NdFeB) magnets. During the HD process, the …The subject of this paper is method (4) together with other aspects of the use of hydrogen in the processing of NdFeB-type magnets. 2. The hydrogen decrepitation process The manufacture of rare earth-transition metal magnets by the HD route was first proposed in a 1978 patent by Harris et al. [7].The nature of hydrogen decrepitation when applied to a cast Nd-Fe-B permanent magnet alloy has been studied by following the microstructural changes on polished surfaces of the material exposed to hydrogen at a pressure of 4 bar. The milling of the material decrepitated at a pressure of 10 bar has also been studied by determining …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 thisJan 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 ... Keywords: Finite difference method; Kinetics; Hydrogen decrepitation; NdFeB alloys; Diffusion 1. Introduction Sv (V ) expansion due to decrepitation results in a five orders of magnitude higher rate of hydrogen diffusion into The most popular recent application of hydrogen in the Nd–Fe–B alloy than into a theoretical bulk sample of that ...Oct 1, 2015 · 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 sintered magnets ... These magnets were identical in every way apart from the orientation of the Nd 2 Fe 14 B grains. Each magnet was exposed to hydrogen and the decrepitation behaviour observed. The anisotropic samples were found to decrepitate exclusively from the ends of the rods whereas the isotropic magnets were attacked by the hydrogen at all …As starting materials, magnets of different grades were used, which were processed by hydrogen decrepitation and blending the powder with NdH x. Composition inhomogeneity in the Nd 2 Fe 14 B-based magnetic phase grains in the recycled magnets and the existence of a core-shell structure consisting of a Nd-rich (Dy-depleted) core and …Jan 1, 2022 · The SC alloy is converted into a fine powder by hydrogen decrepitation and then jet-milling (JM) to produce a fine powder consisting almost entirely of single crystal particles of the Nd 2 Fe 14 B phase. This powder is then filled into fills molds and pressed while a magnetic field is applied to orient the individual particles. The compacted ... 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 ...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 nature of hydrogen decrepitation when applied to a cast Nd-Fe-B permanent magnet alloy has been studied by following the microstructural changes on polished surfaces of the material exposed to hydrogen at a pressure of 4 bar. The milling of the material decrepitated at a pressure of 10 bar has also been studied by determining …The oxidation kinetics in air of a commercial NdFeB magnet have been investigated over the temperature range 335–500°C. The oxide microstructure has been characterized by SEM, XRD and cross-sectional TEM. The results show that the external scale formed consists of an outer layer of Fe2O3 and an inner layer of Fe3O4 but that the principal degradation …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 …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. A Hydrogen Decrepitation Press-Less Process (HD-PLP) recycling method for recycling of anisotropic NdFeB magnets is demonstrated. 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 graphite mold.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, …A high performance sintered NdFeB magnet with N52 was prepared by strip casting, hydrogen decrepitation, jet milling, rubber isostatic pressing with impulse magnetic field and vibrating. The structure of the magnet was investigated by XRD, optical microscope, TEM and SEM, and its demagnetization curve was tested by magnetograph. The results …As starting materials, magnets of different grades were used, which were processed by hydrogen decrepitation and blending the powder with NdH x. Composition inhomogeneity in the Nd 2 Fe 14 B-based magnetic phase grains in the recycled magnets and the existence of a core-shell structure consisting of a Nd-rich (Dy-depleted) core and …May 8, 2023 · 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 ... 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. Originated by Professor Rex Harris, the hydrogen decrepitation method, which is used to reduce NdFeB alloys to a powder, is now ubiquitously employed in worldwide magnet processing.Absorption and desorption of hydrogen by the permanent magnet material Nd 2 Fe 1 4 B have been studied using a microcomputer‐controlled, thermomanometric analyzer with an initial hydrogen pressure of approximately 1 bar. Primary absorption occurs in the range 200–300 °C and results in the formation of a stable hydride with …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 …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 ... 0.5% -1%. Dysprosium (Dy) 0.8% -1.2%. The method of manufacture of Neodymium Iron Boron magnets is as follows: The Neodymium metal element is initially separated from refined Rare Earth oxides in an electrolytic furnace. The “Rare Earth” elements are lanthanoids (also called lanthanides) and the term arises from the uncommon oxide …Feb 5, 2009 · 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 and in ... 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 ... The extracted NdFeB powder is of a purity whereby it can be re-processed into new magnetic materials or rare earth alloys. HyProMag Ltd will be targeting a wide range of end of life applications. Illustration of the HPMS process applied to the voice coil assembly of a hard disk drive. Pilot HPMS reactor capable of processing 5kg of NdFeB.Jul 15, 2015 · The obtained strips were pulverized and further milled into ∼5 μm powder using hydrogen decrepitation and jet milling, respectively. These powders were pressed in a magnetic field of 1.8 T under a pressure of 8.0 MPa. Afterward, the green compacts were sintered at 1070°C for 3 h in vacuum, cooled by Ar quenching. Hydrogen decrepitation and recycling of NdFeB-type sintered magnets. M Zakotnik, E Devlin, IR Harris, AJ Williams. Journal of iron and steel research, international 13, 289-295, 2006. 57: 2006: Life cycle assessment of emerging technologies on value recovery from hard disk drives.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 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 behavior of hydrogen absorption and release in hydrogen decrepitation (HD) process of Nd-Fe-B alloys were investigated. The results reveal that the reactivity and the amount of hydrogen absorption in HD process are related to the surface activity of the alloy so that the fresh and active surface has a higher efficiency. The presence of Nd-rich phase at the …The room temperature hydrogenation causes decrepitation of the material, where the Nd-rich material forms NdH 2.7 and the Nd 2 Fe 14 B matrix grains form an interstitial hydrogen solution. The material expands by ∼5% and because of its brittle nature and differential expansion, undergoes decrepitation [16].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 ... 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. Hydrogen decrepitation and recycling of NdFeB-type Fig. 1. Illustration of the Hydrogen DecrepitationAbstract. This paper reports the desorption of hydrogen fro
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Jan 1, 2022 · The SC alloy is converted into a fine powder by hydrogen decrepitation and then jet-milling (JM) to produce a fine powder consisting almost entirely of single crystal particles of the Nd 2 Fe 14 B phase. This powder is then filled into fills molds and pressed while a magnetic field is applied to orient the individual particles. The compacted ... 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.(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... Hydrogen Decrepitation is a known process for breaking rare earth alloys such as NdFeB into powder, as described by Zakotnik et al. (“Hydrogen Decrepitation and Recycling of Sintered NdFeB-type Sintered Magnets”, Proceedings of 19 th International Workshop on Rare Earth Permanent Magnets & Their Applications; pp 289-295).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 …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 ... Abstract. This paper reports the desorption of hydrogen from NdFeB powder, and unmilled material, produced using hydrogen decrepitation as a pre-milling technique, 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 …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 ... 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 …Permanent magnets produce magnetic fields and maintain the field even in the presence of an opposing magnetic field. They are widely used in electric machines, electronics, and medical devices. Part I reviews the conventional manufacturing processes for commercial magnets, including Nd-Fe-B, Sm-Co, alnico, and ferrite in cast and …Keywords: Finite difference method; Kinetics; Hydrogen decrepitation; NdFeB alloys; Diffusion 1. Introduction Sv (V ) expansion due to decrepitation results in a five orders of magnitude higher rate of hydrogen diffusion into The most popular recent application of hydrogen in the Nd–Fe–B alloy than into a theoretical bulk sample of that ...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 Nd 2 Fe 14 B phase is the main component of sintered NdFeB magnets. The ternary NdFeB phase diagram (Fig. 5.1(a)) shows that there are five phases in addition to the Nd 2 Fe 14 B (T1) phase: Fe, Nd 2 Fe 17, Nd 5 Fe 17, Nd 1.1 Fe 4 B 4 (T2), and Nd.Sintered NdFeB magnets are produced by the liquid phase sintering process and the …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 …In recent years, under the background of global low-carbon development, the production of NdFeB magnets has increased dramatically. With the end of magnet life, a large number of discarded products will be produced in the future. At the same time, 6–73% of industrial waste will be produced in the manufacturing process of magnets. The rare …Hydrogen decrepitation as a highly efficient and excellent crushing method is widely used in the preparation of NdFeB magnets. ... Expand. 1. Save. The processing and characterisation of recycled NdFeB based magnets. S. Adrwish. Materials Science, Engineering. 2013; The scrap magnets were turned into a powder using the HD process. …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 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 The nature of hydrogen decrepitation when applied to a cast Nd-Fe-B permanent magnet alloy has been studied by following the microstructural changes on polished surfaces of the material exposed to hydrogen at a pressure of 4 bar. The milling of the material decrepitated at a pressure of 10 bar has also been studied by determining …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 …Aug 4, 2022 · 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... 1. Introduction. 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], …Originated by Professor Rex Harris, the hydrogen decrepitation method, which is used to reduce NdFeB alloys to a powder, is now ubiquitously employed in worldwide magnet processing.Abstract: Hydrogen decrepitation (HD) is an effective and environmentally friendly technique for recycling of neodymium-iron-boron (NdFeB) magnets. During 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.Hydrogen decrepitation (HD) is an effective and environmentally friendly technique for recycling of neodymium-iron-boron (NdFeB) magnets. During the HD process, the …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 …The Nd 2 Fe 14 B phase is the main component of sintered NdFeB magnets. The ternary NdFeB phase diagram (Fig. 5.1(a)) shows that there are five phases in addition to the Nd 2 Fe 14 B (T1) phase: Fe, Nd 2 Fe 17, Nd 5 Fe 17, Nd 1.1 Fe 4 B 4 (T2), and Nd.Sintered NdFeB magnets are produced by the liquid phase sintering process and the …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 …hydrogen uptake (2043.76 μmol∙g-1) was received NdFeB permanent magnets have different life c
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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.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 …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 …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 …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) …Magnetic powders for sintered NdFeB magnets have been prepared by using an advanced processing method including strip casting, hydrogen decrepitation, jet milling and rubber isotropic press. The effects of Dy, Ga and Co addition on the microstructure and magnetic properties of sintered magnets have been investigated. By adopting a suitable …Step #5 Hydrogen Decrepitation While the grains are very small from strip casting, the material from strip casting comes out of the caster in sheets that must be reduced to powder in order to make magnets. The next step after this is Hydrogen Decrepitation –a process that introduces hydrogen to purposely disintegrate the magnet material. High-temperature oxidation resistance of Nd–Fe–B magnetic powder is of great importance for its application in bonded magnet fields. In this work, the refinement and surface modification of Nd–Fe–B magnetic powders were integrated and achieved simultaneously. The effects of phosphoric acid, isopropyl tris-(dioctyl pyrophosphate …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].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 …A Hydrogen Decrepitation Press-Less Process (HD-PLP) recycling method for recycling of anisotropic NdFeB magnets is demonstrated. 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 graphite mold.The Hydrogen Decrepitation process (HD) is used as an alternative method of powder preparation in the manufacturing process of sintered Nd Fe B magnets [ 1]. During the HD process a NdFeB-type material is hydrogenated by gaseous hydrogen at atmospheric (or elevated) pressure at room (or elevated) temperature.Jul 1, 2019 · Recycling of scrap sintered Nd–Fe–B magnets as anisotropic bonded magnets via hydrogen decrepitation process. 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…. So exposure at LOW temperature to hydrogen leads the NdFeB pieces to react via intergranular fracturation (decrepitation), the mass of Nd2Fe14B grains forminfg a metal hydride with max ...The Hydrogen Decrepitation process (HD) is used as an alternative method of powder preparation in the manufacturing process of sintered Nd Fe B magnets [ 1]. During the HD process a NdFeB-type material is hydrogenated by gaseous hydrogen at atmospheric (or elevated) pressure at room (or elevated) temperature.Another example of the coercivity recovery in crushed NdFeB-type sintered magnets was made by adding the DyF 3 salt [8]. Furthermore, the production of anisotropic RE–Fe–B–Cu powders have also been produced by hydrogen decrepitation of hot deformed ingots [9] followed by degassing.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. 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 Nd-Fe-B (Neomax) alloys and the ND-Dy-Fe-Nb-B high coercivity alloys. The magnets produced by the HD/JM process showed excellent coercivities when …Abstract. This paper reports the room temperature hydrogen decrepitation (HD) of fully dense, 2/17-type sintered magnets based on the composition, Sm (Co 0.69 Fe 0.21 Cu 0.068 Zr 0.019) 7.49. These magnets absorb significant amounts of hydrogen over an extended period (∼48 h) at room temperature and at a pressure of 10 bar to give a …Nov 15, 1988 · 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. Dec 25, 2017 · Recycling of Nd-Fe-B magnets