Rapidly Solidified Neodymium-Iron-Boron Permanent Magnets PDF Download
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Author: John J. Croat
Publisher: Woodhead Publishing
ISBN: 0081022263
Category : Technology & Engineering
Languages : en
Pages : 384
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Book Description
Rapidly Solidified Neodymium-Iron-Boron Permanent Magnets details the basic properties of melt spun NdFeB materials and the entire manufacturing process for rapidly solidified NdFeB permanent magnets. It covers the manufacturing process from the commercial production of the melt spun or rapidly solidified powder, to the production and properties of both isotropic bonded Nd and hot deformed anisotropic NdFeB magnets. In addition, the book discusses the development and history of bonded rare earth transition metal magnets and the discovery of the NdFeB compound, also covering melt spun NdFeB alloys and detailing the magnetization process and spring exchange theory. The book goes over the production of melt spinning development, the operation of a melt spinner, the processing of melt spun powder, commercial grades of NdFeB magnetic powder and gas atomized NdFeB magnetic powders. Lastly, the book touches on the major application and design advantages of bonded Nd Magnets. Features a unique perspective as the author is not only the inventor of NdFeB magnetic powder, but also played a key role in developing many of the technologies covered Provides a comprehensive look at the history, fundamental properties, production processes, design and applications of bonded NdFeB magnets Includes discussion of the rare earth supply challenge, politics, and systems as it impacts bonded NdFeB magnets
Author: John J. Croat
Publisher: Woodhead Publishing
ISBN: 0081022263
Category : Technology & Engineering
Languages : en
Pages : 384
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Book Description
Rapidly Solidified Neodymium-Iron-Boron Permanent Magnets details the basic properties of melt spun NdFeB materials and the entire manufacturing process for rapidly solidified NdFeB permanent magnets. It covers the manufacturing process from the commercial production of the melt spun or rapidly solidified powder, to the production and properties of both isotropic bonded Nd and hot deformed anisotropic NdFeB magnets. In addition, the book discusses the development and history of bonded rare earth transition metal magnets and the discovery of the NdFeB compound, also covering melt spun NdFeB alloys and detailing the magnetization process and spring exchange theory. The book goes over the production of melt spinning development, the operation of a melt spinner, the processing of melt spun powder, commercial grades of NdFeB magnetic powder and gas atomized NdFeB magnetic powders. Lastly, the book touches on the major application and design advantages of bonded Nd Magnets. Features a unique perspective as the author is not only the inventor of NdFeB magnetic powder, but also played a key role in developing many of the technologies covered Provides a comprehensive look at the history, fundamental properties, production processes, design and applications of bonded NdFeB magnets Includes discussion of the rare earth supply challenge, politics, and systems as it impacts bonded NdFeB magnets
Author: Ruel Anthony Overfelt
Publisher:
ISBN:
Category : Alloys
Languages : en
Pages : 290
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Book Description
Author: G. C. Hadjipanayis
Publisher:
ISBN:
Category :
Languages : en
Pages : 5
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Book Description
In early in 1985 the potential of FeNd (Pr) B (SI) alloys for permanent magnet development was demonstrated. The progress under consideration was initiated in April 1983, to study the properties of these materials in more details and in particular to understand the origin of magnetic hardening by correlating the magnetic properties with the microstructure determined by transmission electron microscopy. The magnetic properties of melt-spun Fe-R-B alloys have been examined in the whole rare-earth series. The tetragonal Fe14R2B phase occurs in all alloys studied except in Eu and Yb containing alloys. The Curie temperature of this phase increases from about 170C in Fe14CeB to 375 for Fe14Gd2B and then decreases for the heavier rare-earths and is only 320 C in Fe14Ho2B. In heavy rare-earths, a second phase with a higher Curie temperature approx.(470 C) has also been observed. The nature of this phase is not yet known. The magnetic hysteresis properties of melt-spun Fe-light rare-earth-boron alloys were examined and maximum coercivities were found to scale with the anisotropy fields.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Rapid solidification of novel mixed rare earth-iron-boron, MRE2Fe14B (MRE = Nd, Y, Dy; currently), magnet alloys via high pressure gas atomization (HPGA) have produced similar properties and structures as closely related alloys produced by melt spinning (MS) at low wheel speeds. Recent additions of titanium carbide and zirconium to the permanent magnet (PM) alloy design in HPGA powder (using He atomization gas) have made it possible to achieve highly refined microstructures with magnetic properties approaching melt spun particulate at cooling rates of 105-106K/s. By producing HPGA powders with the desirable qualities of melt spun ribbon, the need for crushing ribbon was eliminated in bonded magnet fabrication. The spherical geometry of HPGA powders is more ideal for processing of bonded permanent magnets since higher loading fractions can be obtained during compression and injection molding. This increased volume loading of spherical PM powder can be predicted to yield a higher maximum energy product (BH){sub max} for bonded magnets in high performance applications. Passivation of RE-containing powder is warranted for the large-scale manufacturing of bonded magnets in applications with increased temperature and exposure to humidity. Irreversible magnetic losses due to oxidation and corrosion of particulates is a known drawback of RE-Fe-B based alloys during further processing, e.g. injection molding, as well as during use as a bonded magnet. To counteract these effects, a modified gas atomization chamber allowed for a novel approach to in situ passivation of solidified particle surfaces through injection of a reactive gas, nitrogen trifluoride (NF3). The ability to control surface chemistry during atomization processing of fine spherical RE-Fe-B powders produced advantages over current processing methodologies. In particular, the capability to coat particles while 'in flight' may eliminate the need for post atomization treatment, otherwise a necessary step for oxidation and corrosion resistance. Stability of these thin films was attributed to the reduction of each RE's respective oxide during processing; recognizing that fluoride compounds exhibit a slightly higher (negative) free energy driving force for formation. Formation of RE-type fluorides on the surface was evidenced through x-ray photoelectron spectroscopy (XPS). Concurrent research with auger electron spectroscopy has been attempted to accurately quantify the depth of fluoride formation in order to grasp the extent of fluorination reactions with spherical and flake particulate. Gas fusion analysis on coated powders (dia.
Author: Shuming Pan
Publisher: Springer
ISBN: 3642363881
Category : Science
Languages : en
Pages : 290
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Book Description
The process of high temperature phase transition of rare earth permanent-magnet alloys is revealed by photographs taken by high voltage TEM. The relationship between the formation of nanocrystal and magnetic properties is discussed in detail, which effects alloys composition and preparation process. The experiment results verified some presumptions, and were valuable for subsequent scientific research and creating new permanent-magnet alloys. The publication is intended for researchers, engineers and managers in the field of material science, metallurgy, and physics. Prof. Shuming Pan is senior engineer of Beijing General Research Institute of Non-ferrous Metal.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
A method of making a permanent magnet wherein 1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and 2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries. The crystallized particulates are consolidated at an elevated temperature to form a shape. During elevated temperature consolidation, the primary and secondary precipitates act to pin the grain boundaries and minimize deleterious grain growth that is harmful to magnetic properties.
Author: Jane W. Lyman
Publisher:
ISBN:
Category : Mineral industries
Languages : en
Pages : 40
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Book Description
Author: G. C. Hadjipanayis
Publisher:
ISBN:
Category :
Languages : en
Pages : 16
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Book Description
The magnetic and structural properties of Fe-R-B magnets were studied in the melt-spun and sintered state. The formation of Fe14R2B phase including its magnetic properties (Curie temperature, magnetic moment and coercivity) and the effects of partial substitutions of iron, rare-earth and metalloid were studied in melt-spun samples. The magnetic properties of as-cast Fe-R-B powders were examined as a function of particle size. The fine powders were sintered into dense magnets and the properties of the magnets were examined over a range of temperatures. The magnetic properties of all samples (melt-spun, powders and sintered magnets) were correlated with the microstructure and magnetic domain structure in an attempt to elucidate the origin of magnetic hardening in these materials. The results of these studies indicate that the high coercivities are due to domain wall pinning at grain boundaries in ribbons and sintered magnets and at the surface of the particles in powders. Keywords: Permanent magnet materials; Iron; Rubidium; Boron; Magnetic hardening; Rare earth alloys. (jes).
Author: Steven A. Attanasio
Publisher:
ISBN:
Category :
Languages : en
Pages : 389
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Book Description
Author: Liebermann
Publisher: CRC Press
ISBN: 1482233991
Category : Technology & Engineering
Languages : en
Pages : 808
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Book Description
This volume details the principles underlying rapid solidification processing, material structure and properties, and their applications. This practical resource presents a manifold approach to both amorphous and crystalline rapidly solidified metallic alloys.;Written by over 30 internationally acclaimed specialists in their respective fields, Rapi