hydrogen crused ndfeb powder

High-Thermostability Nd-Fe-B Magnet Formed by …

2021-7-30 · NdFeB powder would form coarse crystals with the grain size exceeding 10 μm. In general, coercivity increases with decreasing crystal grain size. In the aforementioned coarse condition, the product will lose its magnetic functionality at around 100°C. However, by heating the NdFeB powder in a hydrogen gas atmosphere at 700°C to 900°C, Nd

Hydrogen decrepitation of sintered NdFeB magnets …

1994-3-1 · 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 {approximately} 1000{degrees}C.

[PDF] Recycling of Nd-FeB magnets by hydrogen …

Corpus ID: 172131688. Recycling of Nd-FeB magnets by hydrogen processing and re-sintering @inproceedings{Herriz2016RecyclingON, title={Recycling of Nd-FeB magnets by hydrogen processing and re-sintering}, author={E. Herr{''a}iz and M. Degri and A. Bradshaw and R. Sheridan and V. Mann and I. R. Harris and A. and Lixandru and I. Poenaru and K. Guth and R. Gauss and O. Gutfleisch and A. …

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Bonded Neo Powder NdFeB Powder magnetic powder compound rare earth Yuhong Magnetic Materials Co., Ltd.

Intermediate phases in the hydrogen disproportionated ...

Transmission electron microscopy studies have been carried out on partially disproportionated NdFeB-type alloys. A new intermediate magnetic (NIM) phase has been identified. Moreover, the lamella structure which subsequently develops from the tetragonal NIM phase comprises a tetragonal NdFe-containing (IL) phase and α-Fe. The experimental data show strong evidence of a well-defined ...

The processing and characterisation of recycled NdFeB …

2014-11-13 · Synopsis A study of the processing and characterisation of sintered NdFeB magnets made from recycled feed stock was undertaken. Initially the hydrogen decrepitated (HD) powder was

Development of NdFeB Magnet through Hydrogen …

After melting and casting, the NdFeB alloy is subject to hydrogen atmosphere. Hydrogen slowly absorbs into the solid alloy and makes it brittle, which upon milling becomes fine powder. Hydrogen is ...

Neodymium Iron Boron (NdFeB)

2021-5-6 · •Hydrogen can be used to efficiently extract NdFeB magnets from electrical devices. •Hydrogen decrepitation reduces the magnets to a demagnetized hydrogenated powder. •The hydrogenated powder can be re-processed into new NdFeB magnets. •Re-processing includes re-sintering, HDDR, re-casting, or refining the alloy powder. Abstract

Fabrication of NdFeB-based permanent rare-earth ...

2014-9-25 · The permanent NdFeB isotropic rare earth magnetic powder was first dispersed in an organic solvent, heptane, via high frequency ultrasonics (24 kHz), employing a horn tip probe in pulse mode (10 s on and 15 s off) for a total time of 2 min. Figure 1 shows SEM micrographs of NdFeB based isotropic magnetic powder that was acquired from Molycorp ...

The use of hydrogen to separate and recycle neodymium …

2021-7-15 · is used extensively to reduce bulk (or strip) cast NdFeB ingots to friable, hydrogenated NdFeB granules/powder, prior to the pro-duction of jet milled powder which is then aligned, compressed and sintered to form fully dense sintered magnets (McGuiness et al., 1986). The hydrogen is then removed during the vacuum sintering process.

The magnetic properties of Nd-Fe-B powders produced by ...

The structures and magnetic properties of Nd-Fe-B and Nd-Fe-Zr-B powders produced by mechanical grinding in hydrogen atmosphere were studied. These powders absorbed hydrogen and the Nd 2 Fe 14 B phase disproportionated into Nd-hydride and α-Fe during the mechanical grinding in hydrogen atmosphere. Heat treatment of the hydrogenated powders in vacuum resulted in desorption of the hydrogen …

Hydrogen Decrepitation Press-Less Process 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. Coercivities up to 534 kA/m were obtained in porous samples based on powder size d < 100 m. Adding a ball milling ...

Recycling of bonded NdFeB permanent magnets using …

NdFeB powder and the ionic liquids was observed. A batch of PA6-bonded magnets was treated with an ionic liquid tributylethylphosphonium diethylphosphate, [P 4442][Et 2PO 4], to selectively remove the poly-meric portion. The PA-free magnet powder was found to retain >90% of its original magnetic properties.

Structure and Magnetic Properties of NdFeB Powder …

An ingot of NdFeB alloy was disintegrated by hydrogen decrepitation (HD). High-energy ball milling technique with hard metal milling elements and balls was employed to refine HD powders down to particle size optimum for magnet processing. The experiments were performed according to experimental plan to optimize the milling parameters regarding particle size, contamination and magnetic ...

(PDF) Residual Hydrogen in Nd-Fe-B HDDR Powder and Its ...

Residual hydrogen in the HDDR-treated Nd12.5Fe80.6B6.4Ga0.3Nb0.2 powder and its effect on the coercivity of consolidated compact of the powder were investigated.

Development of a Co-free NdFeB anisotropic bonded …

The anisotropy of the NdFeB magnetic powder is induced by the control of the reaction rate of the NdFeB alloy and hydrogen, by controlling the hydrogen pressure in the HDDR process. The serviceable temperature is increased by the addition of Dy after the application of the d-HDDR method. An increase in intrinsic coercivity, iHc, from 1.12 MA/m ...

Development of NdFeB Magnet through Hydrogen …

Neodymium based magnets are the powerful permanent magnet of today. This paper will discuss iron based rare earth magnets. NdFeB sintered magnet material has been developed. The magnets are produced by powder metallurgy route involving hydrogen decrepitation technique for making fine powder. After melting and casting, the NdFeB alloy is subject to hydrogen atmosphere.

Targeted hydrogen decrepitation of ndfeb magnets from ...

2013-11-22 · reduce NdFeB magnets to a soft magnetic hydrided powder which can be removed from electronic components (using the hydrogen decrepitation process – HD) [Walton et al, 2012]. The extracted material can be used to re-manufacture new NdFeB …

Magnetic properties and microstructures of the Nd-Fe-B ...

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: 4πI s =9.5 kG, B r =7.7 kG, i H c =9.4 kOe, and (BH) max =12.2 MG Oe. Microstructural studies of these powders showed that they are made of fine crystalline grains of ∼0.3 μm diameter and that these crystalline ...

[PDF] Recycling of Nd-FeB magnets by hydrogen …

Corpus ID: 172131688. Recycling of Nd-FeB magnets by hydrogen processing and re-sintering @inproceedings{Herraiz2016RecyclingON, title={Recycling of Nd-FeB magnets by hydrogen processing and re-sintering}, author={E. Herraiz and M. Degri and A. Bradshaw and R. Sheridan and V. S. Mann and I. Harris and A. and Lixandru and I. Poenaru and K. Guth and R. Gauss and O. Gutfleisch and A. …

Neodymium Iron Boron (NdFeB) in a Hydrogen …

The hydrogen molecule penetrates the basic molecular structure causing a "mechanical stress" inside the molecule. The molecule expands and internal cracking begins. The neodymium rich phase at the boundary absorbs the hydrogen. When the neodymium and hydrogen combine, the resultant material is a powder rather than a solid material.

Hydrogen Embrittlement Failure of NdFeB Magnet

2018-6-5 · Hydrogen gas has been widely used in powder making process of NdFeB magnet. The main phase and Nd-rich phase of NdFeB casting piece will generate lattice expansion after absorbed hydrogen, hence cause the integranular fracture and …

Thermal aging of melt-spun NdFeB magnetic powder in …

2016-11-1 · Our results strongly suggest that hydrogen is indeed a major contributor to thermal aging of melt-spun NdFeB powder. 2. Experimental details. Melt-spun NdFeB powder was injection molded by outside vendors to form 1 cm cubes or 1 cm diameter x 1 cm high cylinders using nylon or polyphenylene sulfide (PPS) as the binding agent. CM magnets were ...

Hydrogen Decrepitation Press-Less Process Recycling of ...

Anisotropic NdFeB powder was produced in all cases with the best magnetic properties achieved at a processing temperature of 880 °C, producing powder with a remanence of 1.10(±0.02) T and an ...

Fabrication of Sub-Micron Near Stoichiometric NdFeB ...

2020-3-25 · Index Terms-Near Stoichiometry NdFeB, HDDR, isotropic powder I. INTRODUCTION The hydrogenation dispr portionation desorption and recombination (HDDR) process is a promising new processing route for the production ofNdFeB powder. When NdFeB-type alloys are heated in hydrogen to above 650°C, the

Hydrogen Compared with Other Fuels | Hydrogen Tools

Hydrogen''s flammability range (between 4% and 75% in air) is very wide compared to other fuels, as shown in Figure 3. Under the optimal combustion condition (a 29% hydrogen-to-air volume ratio), the energy required to initiate hydrogen combustion is much lower than that required for other common fuels (e.g., a small spark will ignite it), as shown in Figure 4.

Critical hydrogen pressure for HDDR-formed NdFeB …

2020-12-11 · Critical hydrogen pressure for HDDR-formed NdFeB powder. H2 pressure dependence degree of anisotropy DOA (black circle) and coercivity Hci, (red square) in HDDR Nd14Fe77.9B7Al1Cu0.1 magnetic powder. DOA is defined as the normalized difference between the remanence at aligned state and that at non-aligned state for the same sample. CMI ...

HYDROGEN''S EFFECTS ON THE PROCESS OF PRODUCING …

Hydrogen is a useful assistant in NdFeB industry. This article studied hydrogen''s effects on the Nd-Dy-Fe-B magnets, with the Nd-rich composition. It showed that hydrogen accelerated the oxidation rate of the coarse Nd-Dy-Fe-B powder after HD process and dropped the sinter

Hydrogen Decrepitation Press-Less Process recycling of ...

2017-11-1 · 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.

Wiki Element:PTNM

Hydrogen reactions. There is a class of reactions that occur when both HYGN and another element are nearby. + -> +. + -> + + 5C, PTNM is sparked. Two at greater than 500C have a 1/1000 chance to perform Cold fusion. This spawns one NBLE, one NEUT, and one PHOT and rarely (1/10) one ELEC. This also generates 1000C and 10 pressure.

Sintered NdFeB Magnets as Anisotropic Bonded Magnets …

2019-3-17 · Sintered NdFeB Magnets as Anisotropic Bonded Magnets via Hydrogen Decrepitation Process. Abstract ... The hydrogen content of powder is more than 2500 ppm when the dehydrogenation temperature is at 550°C. As the dehydrogenation temperature increases to 600°C, the hydrogen content of powder decreases sharply to 66 ppm, which demonstrates that ...

GKN Hydrogen

Hydrogen is generated from electrical energy by electrolysis and fed into storage tanks filled with metal powder. The hydrogen bonds to the metal particles to form metal hydride, a stable and safe compound. With simple adjustments of the temperature, the …

Hydrocyclone Separation of Hydrogen Decrepitated NdFeB

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 …

Compression molding of anisotropic NdFeB bonded …

2021-7-28 · NdFeB magnets are classified into two broad categories of sintered and bonded magnets. Until late 1990''s, sintered magnets were produced through powder metallurgy. More recently, strip casting techniques is dominating higher grade NdFeB magnets.[9, 10] This is followed by sintering and heat treatment. The precursor for sintering involves ...

Thermal aging of melt-spun NdFeB magnetic powder in …

Here we report aging studies of rapidly quenched NdFeB powder in air, ATF, and H 2 gas. Expansion of the NdFeB crystal lattice in both ATF and H 2 identified hydrogen dissociated from the ATF during aging and diffused into the primary NdFeB phase as the probable cause of …

POWDER TECHNOLOGY

2021-6-4 · -SCI:、,8000+ SCI,、。"", ...

Hydrogen Decrepitation and Recycling of NdFeB-type ...

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.

Enhancement of Coercivity of Nd-Fe-B Ultrafine Powders ...

2015-5-18 · Abstract: We describe the enhancement of coercivity of Nd-Fe-B ultrafine powders by the grain boundary diffusion (GBD) process. An effective method for increasing coercivity in Nd-Fe-B sintered magnets is the refinement of the Nd 2 Fe 14 B grains. We decreased the powder size of the grains to ;1 μm m by combining hydrogenation-disproportionation-desorption-recombination, hydrogen ...