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E-book

Title Modern permanent magnets / edited by John Croat and John Ormerod
Published Cambridge : Woodhead Publishing, 2022

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Description 1 online resource
Series Woodhead Publishing series in electronic and optical materials
Woodhead Publishing series in electronic and optical materials.
Contents Front cover -- Half title -- Full title -- Copyright -- Contents -- Contributors -- 1 -- The history of permanent ­magnets -- 1.1 Introduction -- 1.2 Lodestones: the first permanent magnets -- 1.3 Early permanent magnet studies -- 1.4 The era of steel permanent magnets -- 1.5 The discovery of alnico permanent magnets -- 1.6 The discovery of hard ferrite magnets -- 1.7 The discovery of Sm-Co permanent magnets -- 1.8 The discovery of NdFeB permanent magnets -- 1.9 The discovery of Sm-Fe-N permanent magnets -- 1.10 Future permanent magnet materials -- 1.11 Summary -- References -- 2 -- Fundamental properties of permanent magnets -- 2.1 Introduction -- 2.2 The different families and types of permanent magnets -- 2.3 Key magnetic parameters -- 2.4 On the origin of magnetism -- 2.5 The different types of magnetism -- 2.6 The origin of anisotropy in permanent magnets -- 2.7 Magnetic domains and domain walls -- 2.8 Magnetic hysteresis -- 2.9 Coercivity mechanism in modern permanent magnets -- 2.10 Stability of permanent magnets -- References -- 3 -- Recent advances in hard ­ferrite magnets -- 3.1 Introduction -- 3.2 Historical overview of M-type Sr- and Ba- Hexaferrites -- 3.3 Crystal structure, intrinsic magnetic properties, microstructure and morphology -- 3.4 Advances towards the improvement of intrinsic magnetic properties -- 3.5 Industrial fabrication routes -- 3.5.1 Fabrication of hexaferrites -- 3.5.2 Bonded magnets -- 3.5.3 Sintered magnets -- 3.5.4 Additive manufacturing -- 3.6 Recycling efforts, recovery, and reusability in production line -- 3.7 Applications of hexaferrites: present and perspectives -- References -- 4 -- Modern Sm-Co permanent magnets -- 4.1 Introduction -- 4.2 Manufacturing process of Sm-Co magnets -- 4.3 High (BH) max Sm 2 Co 17 type permanent magnets
4.4 Temperature compensated Sm-Co magnets -- 4.5 Ultra-high temperature Sm-Co magnets with small reversible temperature coefficient of B r -- 4.6 Performance of Sm-Co magnets in special environments -- 4.7 Laminated Sm-Co magnets -- 4.8 Additive manufacturing -- 4.9 Small magnets -- 4.10 Sm-Co nanoparticles and nanoflakes for nanocomposite magnets -- 4.11 Summary -- References -- 5 -- The status of sintered NdFeB magnets -- 5.1 Introduction -- 5.2 History of the development of Nd-Fe-B -- 5.2.1 How did the idea of NdFeB sintered magnets come about? -- 5.2.2 How were the NdFeB sintered magnets developed? -- 5.2.3 How was the discovery of NdFeB sintered magnets presented? -- 5.3 Compositions of the NdFeB sintered magnets and their magnetic properties -- 5.4 Production process for sintered NdFeB magnets -- 5.4.1 Preparation of raw material alloys (strip-casting method) -- 5.4.2 Hydrogen decrepitation (HD) -- 5.4.3 Jet milling -- 5.4.4 Application of lubricant to the powder surface -- 5.4.5 Magnetic field pressing -- 5.4.6 Sintering -- 5.4.7 Heat treatment -- 5.4.8 Machining -- 5.4.9 Surface treatment -- 5.4.10 Magnetization -- 5.5 Progress in the microstructure investigation -- 5.6 Development of HRE-Free and reduced HRE magnets -- 5.6.1 Development of the powder-blend method -- 5.6.2 Development of grain boundary diffusion process -- 5.6.3 Ga-doped NdFeB sintered magnets -- 5.6.4 Grain size refinement -- 5.7 Ultimate NdFeB sintered magnets for EV traction motors -- References -- 6 -- Compression bonded NdFeB permanent magnets -- 6.1 Introduction -- 6.2 The compression molding process -- 6.3 Isotropic compression bonded NdFeB permanent magnets -- 6.4 Anisotropic hot deformed NdFeB compression bonded magnets -- 6.5 Compression molded HDDR permanent magnets -- References -- 7 -- Injection molded permanent magnets
7.1 Introduction -- 7.2 Overview of applications, basic parameters and materials -- 7.3 Manufacturing -- 7.4 Polarization patterns -- 7.5 Design of in-mold magnetized magnets -- 7.6 Design of pulse magnetized magnets -- 7.7 Applications -- Sensors -- 7.8 Applications -- Electrical machines -- 7.9 Summary -- Acknowledgments -- References -- 8 -- Hot formed NdFeB magnets -- 8.1 Introduction -- 8.2 Development of hot-formed Nd-Fe-B magnets -- 8.2.1 Previous examples of magnets made by plastic deformation -- 8.2.2 Invention of rapidly quenched Nd-Fe-B and application of hot deformation -- 8.2.3 Early studies and commercialization efforts -- 8.2.3.1 MQ2 and MQ3 (die-upset) commercialization efforts -- 8.2.3.2 Mode of deformation and alignment directions -- 8.2.3.3 Cast and rolled Pr-Fe-B -- 8.2.4 Commercialization of hot-deformed Nd-Fe-B magnets -- 8.2.4.1 Starting powders -- 8.2.4.2 Densification of rapidly quenched powders -- 8.2.4.3 Hot workability -- 8.2.4.4 Development of radially oriented rings -- 8.2.4.5 Rare-earth crisis and need for HREE-free magnets -- 8.2.4.6 Development of axially oriented plates -- 8.3 Characteristics of hot-deformed Nd-Fe-B magnets -- 8.3.1 Basic properties -- 8.3.2 Comparison with sintered Nd-Fe-B -- 8.3.2.1 Microstructure -- 8.3.2.2 Coercivity and thermal stability -- 8.3.2.3 Initial magnetization and minor loops -- 8.3.2.4 Corrosion resistance -- 8.3.2.5 Producibility -- 8.4 Fundamental research -- 8.4.1 Alignment mechanism -- 8.4.2 Coercivity mechanism -- 8.4.3 Grain boundary analyses and modification -- 8.4.4 Other notable research -- 8.5 Applications -- 8.5.1 Radially oriented rings -- 8.5.1.1 FA (Factory automation) servo motors -- 8.5.1.2 EPS (Electric power steering) -- 8.5.1.3 Assembly, magnetizing, banding -- 8.5.2 Axially oriented plates -- 8.5.2.1 EV/HEV traction motors
8.6 Future outlook -- 8.6.1 Addressing resource and cost issues -- 8.6.2 Higher magnetic properties -- 8.6.3 Improvement of electrical resistance -- 8.6.4 Flexible shape extrusions -- 8.7 Concluding remarks -- Acknowledgments -- References -- 9 -- Bonded Sm-Fe-N permanent magnets -- 9.1 Introduction -- 9.2 Interstitial modification -- 9.3 Basic characteristics of Sm-Fe-N compounds -- 9.3.1 Crystal structure -- 9.3.2 Intrinsic magnetic properties -- 9.3.3 Dense Sm-Fe-N magnets -- 9.4 Magnet processing -- 9.4.1 Sm-Fe-N powder -- 9.4.1.1 Anisotropic Sm 2 Fe 17 N 3 powder -- 9.4.1.2 Isotropic SmFe 7-9 N powder -- 9.4.2 Production processes for bonded magnets -- 9.4.3 Magnetic properties of bonded magnets -- 9.5 Applications -- 9.5.1 Features of bonded Sm-Fe-N magnets -- 9.5.2 Application examples -- 9.6 Conclusion -- Acknowledgments -- References -- 10 -- Critical materials for permanent magnets -- 10.1 Introduction -- 10.2 What is a critical material? -- 10.3 Critical materials in permanent magnets -- 10.3.1 Growth of the market -- 10.3.2 The rare earth elements: a general introduction to their science and technology -- 10.3.3 Samarium-Cobalt -- 10.3.3.1 Criticality of samarium -- 10.3.3.2 Criticality of cobalt -- 10.3.4 Neodymium-Iron-Boron -- 10.3.4.1 Criticality of neodymium and praseodymium -- 10.3.4.2 Criticality of dysprosium, terbium and holmium -- 10.4 Effects of criticality on technology evolution, and vice versa -- 10.4.1 Conventional vehicles -- 10.4.2 Electric vehicles -- 10.4.3 Wind power -- 10.5 Source diversification -- 10.5.1 Samarium -- 10.5.2 Cobalt -- 10.5.3 Neodymium and praseodymium -- 10.5.4 Dysprosium, terbium and holmium -- 10.6 Substitution -- 10.6.1 Technology substitutions -- 10.6.1.1 LEDs vs fluorescent lamps, and their impact on magnet materials -- 10.6.2 Material substitutions
10.6.2.1 Using Nd-Fe-B in place of Sm-Co after the cobalt crisis -- 10.6.2.2 Element substitutions within Nd-Fe-B -- 10.6.2.3 Praseodymium and neodymium -- 10.6.2.4 Terbium, dysprosium and holmium -- 10.6.2.5 Substitutes for the Nd-Fe-B family of alloys -- 10.6.2.6 Superconducting magnets -- 10.6.2.7 Gap magnets -- 10.6.2.8 Using Sm-Co in place of Nd-Fe-B -- 10.6.2.9 3-D printing of magnets -- 10.7 Summary -- Acknowledgments -- References -- 11 -- Permanent magnet coatings and testing procedures -- 11.1 Introduction -- 11.2 Magnet characteristics relevant to coating -- 11.2.1 Alnico -- 11.2.2 Ferrite -- 11.2.3 Samarium cobalt -- 11.2.4 Neodymium iron boron -- 11.2.5 Samarium iron nitride (SmFeN) -- 11.2.6 Bonded magnets -- 11.3 Coating permanent magnets -- 11.3.1 Surface preparation -- 11.3.2 Conversion coatings -- 11.3.3 Organic coatings -- 11.3.4 Parylene -- 11.3.5 Metallic plating -- 11.3.6 Aluminum ion vapor deposition (IVD) -- 11.3.7 Combination coatings -- 11.4 Coating test and evaluation -- 11.4.1 Temperatuire and humidity test -- 11.4.2 Autoclave (hygrothermal) test -- 11.4.3 Salt spray (fog) test -- 11.4.4 Other tests -- 11.5 Summary -- References -- 12 -- Permanent magnet markets and applications -- 12.1 Introduction -- 12.2 Permanent magnet materials -- 12.3 Applications and markets -- 12.4 Price/Performance ratio for permanent magnet types -- niche and mass market magnet materials -- 12.5 Current and future major applications and devices ( Constantinides, 2021 -- Benecki et al., 2021 ) -- 12.5.1 Permanent magnet motors -- 12.5.2 Types of motors -- 12.5.3 Motor efficiency -- 12.5.4 Motor size and diversity -- 12.5.5 Information storage: computer hard disk and optical storage drives -- 12.5.6 Industrial and general use motors -- 12.5.7 Permanent magnets in transportation
Bibliography Includes bibliographical references and index
Subject Permanent magnets.
Permanent magnets
Form Electronic book
Author Croat, John J., editor.
Ormerod, J. G. (John G.), editor.
ISBN 9780323886406
032388640X