Includes bibliographical references and index.

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.