Production of anisotropic Nd-Fe-B type magnets, using the HDDR process by Carolyn Lesley Short

Cover of: Production of anisotropic Nd-Fe-B type magnets, using the HDDR process | Carolyn Lesley Short

Published by University of Birmingham in Birmingham .

Written in English

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Thesis (Ph.D) - University of Birmingham, School of Metallurgy and Materials, Faculty of Engineering, 1996.

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Statementby Carolyn Lesley Short.
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Open LibraryOL17325528M

Download Production of anisotropic Nd-Fe-B type magnets, using the HDDR process

Previous methods of producing anisotropic Nd-Fe-B magnets or magnet powders are the field-orientation of magnet powder (sintered mag- nets) and the hot-forming of solid bodies (hot-formed magnets).

It is to be noted that the present HDDR process can only produce anisotropic Nd-Fe-B mag- netic powders by a kind of heat by: Anisotropic Nd–Fe–B magnet powders can be produced by the hydrogenationdecomposition‐desorption‐recombination (HDDR) process from Nd–Fe–B–Co–M (M=Ga, Zr, Nb, Hf, and Ta) by: High-coercivity Nd-Fe-B magnet powders were produced by the HDDR process.

The substitution of Fe with Co and the addition of elements such as Ga, Zr, Nb, Hf and Ta was found to be very effective for enhancing magnetic anisotropy of HDDR magnet Ryoji Nakayama, Takuo Takeshita.

Most previous work undertaken on HDDR processing of sintered NdFeB magnets has led to the production of magnetically isotropic powder, which leads to a significant reduction in the remanence of the powder. The production of anisotropic HDDR powder from cast starting material has been reported from many sources.

However, this has been achieved mostly by introducing additions of cobalt, gallium, zirconium or niobium to alter the kinetics of the HDDR Cited by: Mar 10,  · The anisotropic Nd–Fe–B HDDR powder prepared from the annealed SC alloy flakes exhibits a more uniform microstructure, and possesses higher B r and (BH) max as compared to the powder made using the conventional BMC ingots.

They would be related to the complete elimination of α-Fe phase before the HDDR by: Nd–Fe–B powders produced using the Hydrogenation Disproportionation Desorption Recombination (HDDR) process are useful for the production of high-performance anisotropic bonded by: The production of a Nd-Fe-B permanent magnet by a hydrogen decrepitation/attritor milling route.

Journal of Materials Science,21, p. [10]-Sheridan RS, Williams AJ, Harris IR, Walton A. Improved HDDR processing route for production of anisotropic powder from sintered NdFeB type magnets. Journal of Magnetism. ► Production of anisotropic permanent magnet powder from scrap NdFeB magnets by HDDR. ► Reaction pressure increases with increasing processing temperature.

► Best magnetic properties achieved by processing at ° by: The hydrogenation disproportionation desorption recombination (HDDR) process has been investigated as a possible means of producing bonded magnets from used NdFeB-type sintered magnets. Anisotropic Nd–Fe–B magnet powders can be produced by the hydrogenationdecomposition‐desorption‐recombination (HDDR) process from Nd–Fe–B–Co–M (M=Ga, Zr, Nb, Hf, and Ta) alloys.

In the current study, sintered ferrite magnets were replaced by Nd-Fe-B anisotropic bonded magnets in an effort to reduce the size and weight of the motor.

Abstract. The Hydrogenation Disproportionation Desorption Recombination (HDDR) process can yield anisotropic and highly coercive NdFeB-type powders with energy densities in excess of (BH) max = kJ/m elucidation of the very unusual phenomenon of texture inducement is of great scientific and technological by: 2.

Improved HDDR processing route for production of anisotropic powder from sintered NdFeB type magnets R.S. Sheridan, A.J. Williams, I.R. Harris, A.

Waltonn School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom. Hydrogen processing (HD + HDDR) is used to recycle Nd-Fe-B sintered magnets yielding anisotropic resin bonded magnets (RBM).

HD produces single-crystalline powders from the sintered magnets. Anisotropic resin bonded magnets have been produced by recycling Nd‐Fe‐B sintered magnets using a combined HD and d‐HDDR route. The route was shown to. The anisotropy constants K 1 and (K 2-K 3) of anisotropic Nd-Fe-B magnet powders prepared by the modified HDDR process were obtained from torque measurements in magnetic fields of up to MA/m.

A value of K 1 =×10 6 J/m 3 was obtained by Fourier analysis of an unsaturated torque by: 2. The production process of HDDR anisotropic NdFeB powder The HDDR process is the most important step for anisotropic NdFeB powder.

The HDDR parameters of anisotropic NdFeB powder are much more accurate than the sintered NdFeB magnet. Sep 11,  · Conventional methods for the production of anisotropic (high remanence), nanoscale (high coercivity) Nd-Fe-B-based magnetic materials involve multiple processing steps and typically employ high temperatures, pressures and long processing times; leading to production costs that are several times that of the raw materials by: 6.

This paper reports a method of preparing axially oriented ring-shaped magnets for small motors from anisotropic HDDR powder.

To use this process, it is possible to product an anisotropic Nd-Fe-B-based flexible bonded magnet. These flexible bonded magnets are able to keep a high efficiency, like a radially oriented by: 2.

The HDDR process was then performed on scrap sintered NdFeB magnets, which were separated from HDD assemblies using hydrogen, on a large scale in order to produce anisotropic NdFeB alloy powder.

The HDDR powder was then used to produce injection moulded magnets on pilot scale equipment (5 kg load) at Kolektor Magnet Technology GmbH, by: 1. Anisotropic Nd-Fe-B resin bonded magnet MAGFINE Aichi Steel discovered the manufacturing principles for anisotropic magnetic powder (d-HDDR method) and succeeded in bringing anisotropic bonded magnets to market.

In the hydrogen release process, the Fe B phase is recrystallized and the orientation of the crystals is aligned. That is, the. Anisotropic Nd-Fe-B resin bonded MAGFINE Aichi Steel discovered the manufacturing principles for anisotropic magnetic powder (d-HDDR method) and brought anisotropic bonded magnets to market.

In we also launched our Dy Free products. Product information. Jul 01,  · The HDDR (hydrogenation-disproportionation-desorption-recombination) process is an established powder metallurgy route to obtain Nd–Fe–B nanocrystalline powders for bonded magnets manufacturing.

Therefore, both conventional (c-HDDR) and dynamic HDDR (d-HDDR) processes has been investigated to obtain Nd-Fe-B-based powders with different Juliano Assis Baron Engerroff, Frederico Orlandini Keller, Leonardo Ulian Lopes, Arthur Alvarez Masc.

Various anisotropic Nd-Fe-B magnetic powders were prepared by the dynamic hydrogenation disproportionation desorption recombination (d-HDDR) treatment with different hydrogenation disproportionation (HD) times (t HD).The resulting magnetic properties and microstructural changes were investigated.

The magnetic anisotropy was decreased with increasing t HD. Cited by: 4. Jul 20,  · Our results confirm that the anisotropic HDDR Nd-Fe-B magnetic powders prepared directly from the SC alloy flakes without homogenizing treatment can be obtained. Effects of the wheel speeds v and disproportionation time during the SC-HDDR process on the properties of Nd-Fe-B magnetic powders are by: 1.

Our d-HDDR technology evolved with the discovery of anisotropic mechanics giving additional performance to the magnetic powder.

InAichi Steel developed a new heat resistant Dy-free MAGFINE ® magnetic powder. These are our MF15P and MF18P products. Using this magnetic powder in compression molding are our MF14C, MF16C and MF18C products. Hydrogen decrepitation (HD) and Hydrogen decrepitation deabsorbation recombination (HDDR) process is widely used in preparation of powder for NdFeB magnet.

This process allow to crush strip casted material to powder ranging micron meter size. Abstract: Bulk anisotropic Nd−Fe−B magnets were prepared from hydrogen−disproportionation−desorption−recombination (HDDR) powders via spark plasma sintering (SPS) and subsequent hot deformation.

The influence of sintering temperature on the structure and magnetic properties of the spark plasma sintered Nd−Fe−B magnets were studied.

Improved HDDR processing route for production of anisotropic The HD process has also been used as a way of separating LUO Jianjun Development of anisotropic Nd-Fe-B powders from Mar 3, Hydrogen decrepitation and desorption furnace NdFeB-type magnets and with the growing environmental need to conserve both.

Disclosed are an Nd-Fe-B based magnet and a manufacturing method thereof. According to one aspect of the present invention, the Nd-Fe-B based magnet including crystal grains and crystal grain boundaries has the diameter of the crystal grain about μm, and an aspect ratio of the crystal grain is greater than and less than 이정구, 차희령, 김영국, 백연경.

In this paper it is shown that anisotropic NdFeB-magnets can also be achieved by hot extrusion of cast samples.

This procedure is similar to the process used for the production of high grade anisotropic MnAlC-magnets. Such a process avoids the pulverisation operation Cited by: 1. sub-micron grain structure.

Most often HDDR processing produces an isotropic magnet powder, but through elemental additions it is possible to produce an anisotropic powder. It is the HDDR process that is being used to produce anisotropic Nd 2Fe 14B powders for use in polymer bonded magnets. A neodymium magnet (also known as NdFeB, NIB or Neo magnet) is the most widely used type of rare-earth magnet.

It is a permanent magnet made from an alloy of neodymium, iron, and boron to form the Nd 2 Fe 14 B tetragonal crystalline structure. Abstract. The study on the preparation of anisotropic powders from hot-extruded Pr-Fe-B-Cu alloys has been carried out.

It is shown that the method of equal channel angular pressing allows producing Pr-Fe-B-Cu alloys as fine-grain bulk precursors with high coercivity and the radial orientation of the Pr 2 Fe 14 B easy axes.

The precursors were pulverized by both mechanical grinding and Cited by: 1. It is reported that Nd‐Fe‐B magnetic powders prepared by utilizing the HDDR (hydrogenation, disproportionation, desorption, and recombination) phenomena exhibit high coercivity, and the addition of Co, Ga, and Zr induces magnetic anisotropy in these powders.

HDDR phenomena are caused by the heat treatment in hydrogen (H treatment) and subsequently in vacuum (V treatment).Cited by: The recovery of neodymium from Nd-Fe-B magnets, pertaining to the industry of magnets or hard magnetic objects made of inorganic materials containing elements belonging to the lanthanide group in the form of microparticles consisting of nanoscale grains, relates to recycling Nd-Fe-B magnets for recovering neodymium, more specifically by reacting hydridated magnet powder, consisting of NdHy Cited by: 1.

Feb 01,  · Abstract: Pr14FebalCoxB6Nb magnets have been produced using the hidrogenation disproportionation desorption recombination (HDDR) process. The effect of the Co content (x= 0, 4, 8, 10, 12, 16) and the reaction temperature ( °C) on the microstructure and magnetic properties of the HDDR material have been by: 3.

A historical survey, the basic magnetic properties of Nd 2 Fe 14 B and isomorphous compounds, a phase diagram for the ternary Nd–Fe–B system, processing techniques and magnetic properties of sintered Nd–Fe–B magnets, and the future directions for improvements of this type of permanent magnet are by: Abstract: Rare earth iron boron magnets based on Nd 2 Fe 14 B type is the most powerful permanent magnets, which have outstanding magnetic properties in the vicinity of room temperature.

Production of NdFeB is carried out by two distinctly different processes. These include the conventional powder - sintering process and consolidation of rapidly solidified powders. A Review of Nd-Fe-B Permanent Magnets and their use in Maglev Inductrack System Darrell R Montonera Illinois Institute of Technology October 15, INTRODUCTION Transportation is of increasing importance as the worlds countries try to diminish pollution and travel time.

1. Introduction. Neodymium- and praseodymium-based bonded magnets can be successfully prepared by the HDDR process Isotropic magnets are prepared using the basic alloy without additions and anisotropic with the additions of cobalt, gallium, zirconium and niobium.Specific features of the interaction of alloys of the didymium-iron-boron system with hydrogen “The use of hydrogen in the production of Nd–Fe–B-type magnets and in the assessment of Nd–Fe–B H.

Mitarai, and Y. Honkura, “Enhancement of heat resistance of Nd–Fe–B anisotropic magnet by Dy addition in HDDR process,” in Cited by: 1.Nd-Fe-B as-cast alloys in the form of small ingots mm thick and with composition Nd{sub }Fe{sub 14}B were transformed into high coercivity magnets using the hydrogenation disproportionation desorption (HDD) process without decrepitation of the blocks taking place.

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