HANDBOOK OF ELECTRICAL STEEL 1122000077__99778899881111222266991155__TTPP..iinndddd 11 2211//99//2211 88::1177 AAMM B1948 Governing Asia TTTThhhhiiiissss ppppaaaaggggeeee iiiinnnntttteeeennnnttttiiiioooonnnnaaaallllllllyyyy lllleeeefffftttt bbbbllllaaaannnnkkkk BB11994488__11--AAookkii..iinndddd 66 99//2222//22001144 44::2244::5577 PPMM HANDBOOK OF ELECTRICAL STEEL Göran Engdahl The KTH Royal Institute of Technology, Sweden NEW JERSEY • LONDON • SINGAPORE • BEIJING • SHANGHAI • HONG KONG • TAIPEI • CHENNAI • TOKYO 1122000077__99778899881111222266991155__TTPP..iinndddd 22 2211//99//2211 88::1177 AAMM Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. HANDBOOK OF ELECTRICAL STEEL Copyright © 2022 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN 978-981-122-691-5 (hardcover) ISBN 978-981-122-692-2 (ebook for institutions) ISBN 978-981-122-693-9 (ebook for individuals) For any available supplementary material, please visit https://www.worldscientific.com/worldscibooks/10.1142/12007#t=suppl Typeset by Stallion Press Email: [email protected] Printed in Singapore LLaakksshhmmii -- 1122000077 -- HHaannddbbooookk ooff EElleeccttrriiccaall SStteeeell..iinndddd 11 1177//99//22002211 1122::1155::5577 ppmm September17,2021 13:33 HandbookofElectricalSteel-9inx6in b3998-fm pagev Contents Preface xvii Concluding Remarks xxiii Acknowledgements xxv Chapter 1. A Brief Introduction to Magnetism and Magnetic and Electric Fields 1 1.1 History of Magnetism . . . . . . . . . . . . . . . . . . . 1 1.2 Some Basic Electromagnetism . . . . . . . . . . . . . 3 1.2.1 The magnetic induction field. . . . . . . . . 3 1.2.2 The electric field . . . . . . . . . . . . . . . . 8 1.2.3 The electric dipole moment and the displacement field . . . . . . . . . . . . . . . . 10 1.2.4 Magnetic moments . . . . . . . . . . . . . . . 12 1.2.5 Magnetic moments and the magnetizing field . . . . . . . . . . . . . . . . . . . . . . . . . 12 1.2.6 The magnetization field . . . . . . . . . . . . 17 1.2.7 The demagnetizing field . . . . . . . . . . . . 19 1.2.8 The Maxwell’s equations . . . . . . . . . . . 24 1.2.9 Magnetic field calculations . . . . . . . . . . 25 1.2.10 Material laws . . . . . . . . . . . . . . . . . . . 28 1.2.11 Electric and magnetic potentials . . . . . . 30 1.2.12 Electromotive and magnetomotive forces . . . . . . . . . . . . . . . . . . . . . . . . 33 v September17,2021 13:33 HandbookofElectricalSteel-9inx6in b3998-fm pagevi vi Handbook of Electrical Steel 1.2.13 Dielectric and magnetic media boundaries . . . . . . . . . . . . . . . . . . . . 37 1.2.14 The magnetic field outside and inside magnetic materials . . . . . . . . . . . . . . . 42 1.2.15 Magnetic forces and magnetic energy . . . 45 1.2.16 Some thermodynamics of magnetic materials . . . . . . . . . . . . . . . . . . . . . 56 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Chapter 2. The Quantum Mechanical Nature of Magnetic Material 61 2.1 Some Basic Quantum Mechanics . . . . . . . . . . . 67 2.2 Electron Spin and Orbitals . . . . . . . . . . . . . . . 72 2.3 The Free-Electron Model . . . . . . . . . . . . . . . . 82 2.4 Atomic Magnetism . . . . . . . . . . . . . . . . . . . . 89 2.4.1 The one-electron atom . . . . . . . . . . . . . 89 2.4.2 Addition of angular momenta of the electrons . . . . . . . . . . . . . . . . . 95 2.4.3 Curie law of paramagnetism . . . . . . . . . 97 2.4.4 Pauli susceptibility . . . . . . . . . . . . . . . 98 2.4.5 Several electron atoms . . . . . . . . . . . . . 100 2.4.6 Spin–orbit coupling . . . . . . . . . . . . . . . 115 2.4.7 Theory of electronic magnetism . . . . . . . 117 2.5 Magnetism and Relativity . . . . . . . . . . . . . . . . 119 2.6 Zeeman Interaction . . . . . . . . . . . . . . . . . . . . 121 2.7 Paramagnetism . . . . . . . . . . . . . . . . . . . . . . . 124 2.8 Molecules. . . . . . . . . . . . . . . . . . . . . . . . . . . 130 2.8.1 Solid materials . . . . . . . . . . . . . . . . . . 140 2.9 Covalent solids . . . . . . . . . . . . . . . . . . . . . . . 141 2.9.1 Ionic crystals . . . . . . . . . . . . . . . . . . . 142 2.9.2 Hydrogen-bond solids . . . . . . . . . . . . . 143 2.9.3 Molecular solids . . . . . . . . . . . . . . . . . 143 2.9.4 Metals . . . . . . . . . . . . . . . . . . . . . . . 144 2.10 Magnetism of Electrons in Solids . . . . . . . . . . . 146 2.11 Some Basic Solid State Physics . . . . . . . . . . . . 147 2.11.1 Crystal lattices. . . . . . . . . . . . . . . . . . 147 September17,2021 13:33 HandbookofElectricalSteel-9inx6in b3998-fm pagevii Contents vii 2.11.2 Miller indices and crystal directions . . . . 152 2.11.2.1 Some simple closed-packed structures . . . . . . . . . . . . . . 156 2.11.3 Reciprocal space. . . . . . . . . . . . . . . . . 157 2.11.4 Brillouin zones . . . . . . . . . . . . . . . . . . 161 2.11.5 Band theory of solids . . . . . . . . . . . . . 163 2.11.5.1 General features of energy band of electrons . . . . . . . . . . . . . 163 2.11.6 Electron motion in periodic structures . . 167 2.11.6.1 Energy band gaps and overlap . . . . . . . . . . . . . 177 2.12 Electrical Conductivity . . . . . . . . . . . . . . . . . . 180 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 Chapter 3. Ferromagnetism 187 3.1 Mean Field Theory . . . . . . . . . . . . . . . . . . . . 188 3.2 The Landau Theory . . . . . . . . . . . . . . . . . . . . 192 3.3 The Stoner Criterion . . . . . . . . . . . . . . . . . . . 194 3.4 Exchange Interactions . . . . . . . . . . . . . . . . . . 196 3.5 Other Ordered Magnetism. . . . . . . . . . . . . . . . 202 3.5.1 Antiferromagnetism . . . . . . . . . . . . . . 203 3.5.2 Ferrimagnetism . . . . . . . . . . . . . . . . . 205 3.5.3 Miscellaneous ordering. . . . . . . . . . . . . 208 3.5.3.1 Frustration. . . . . . . . . . . . . . 208 3.5.3.2 Amorphous magnets . . . . . . . 209 3.5.3.3 Spin glass . . . . . . . . . . . . . . 211 3.6 Crystal-field Interaction . . . . . . . . . . . . . . . . . 215 3.7 Magnetic Anisotropy . . . . . . . . . . . . . . . . . . . 217 3.7.1 Crystalline magnetic anisotropy . . . . . . . 217 3.7.2 Shape anisotropy . . . . . . . . . . . . . . . . 223 3.7.3 Induced anisotropy . . . . . . . . . . . . . . . 224 3.8 Magnetostriction . . . . . . . . . . . . . . . . . . . . . . 224 3.8.1 Other magnetoelastic effects . . . . . . . . . 226 3.9 Ferromagnetic Domains . . . . . . . . . . . . . . . . . 227 3.9.1 Introduction . . . . . . . . . . . . . . . . . . . 227 3.9.2 Micromagnetic energies . . . . . . . . . . . . 231 September17,2021 13:33 HandbookofElectricalSteel-9inx6in b3998-fm pageviii viii Handbook of Electrical Steel 3.9.2.1 Exchange energy . . . . . . . . . . 232 3.9.2.2 Anisotropy energy . . . . . . . . . 234 3.9.2.3 Demagnetizing energy . . . . . . 235 3.9.2.4 Strain energy . . . . . . . . . . . . 236 3.9.2.5 Magnetostriction energy . . . . . 237 3.9.2.6 Minimization of the micromagnetic energy. . . . . . . 237 3.9.3 Domain walls . . . . . . . . . . . . . . . . . . . 240 3.9.3.1 The Bloch wall . . . . . . . . . . . 240 3.9.3.2 The N´eel wall . . . . . . . . . . . . 243 3.10 The Stoner–Wohlfarth Model. . . . . . . . . . . . . . 251 3.11 The Nucleation Field . . . . . . . . . . . . . . . . . . . 258 3.12 Domain-Wall Motion . . . . . . . . . . . . . . . . . . . 258 3.13 Examples of Real Hysteresis Loops . . . . . . . . . . 263 3.14 Long-Term Magnetization Features . . . . . . . . . . 268 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269 Chapter 4. Magnetic Materials 271 4.1 Soft Magnetic Materials . . . . . . . . . . . . . . . . . 273 4.1.1 Soft magnetic material characterizing quantities . . . . . . . . . . . . . . . . . . . . . 273 4.1.1.1 Coercivity . . . . . . . . . . . . . . 275 4.1.1.2 Permeability. . . . . . . . . . . . . 275 4.1.1.3 Remanence . . . . . . . . . . . . . 278 4.1.1.4 Linearity and hysteresis . . . . . 279 4.1.1.5 Losses . . . . . . . . . . . . . . . . . 280 4.2 Available Materials . . . . . . . . . . . . . . . . . . . . 280 4.2.1 Soft magnetic material classification . . . . 280 4.2.2 Pure iron . . . . . . . . . . . . . . . . . . . . . 284 4.2.3 Conventional grain-oriented (CGO) SiFe steel. . . . . . . . . . . . . . . . . . . . . . . . . 287 4.2.4 High permeability grain-oriented electrical steel HiB . . . . . . . . . . . . . . . . . . . . . 291 4.2.5 Non-oriented electrical steel NO . . . . . . 294 4.2.6 Special iron-based alloys . . . . . . . . . . . 297 4.2.6.1 Rapid solidification . . . . . . . . 297 September17,2021 13:33 HandbookofElectricalSteel-9inx6in b3998-fm pageix Contents ix 4.2.6.2 The CVD process . . . . . . . . . 297 4.2.6.3 Alternative texture . . . . . . . . 299 4.2.6.4 Alternative to silicon . . . . . . . 300 4.2.7 Nickel and Cobalt-based alloys . . . . . . . 301 4.2.7.1 NiFe alloys . . . . . . . . . . . . . . 301 4.2.7.2 Permendur and Perminvar. . . . 304 4.2.8 Amorphous magnetic materials . . . . . . . 305 4.2.9 Nanocrystalline materials . . . . . . . . . . . 310 4.2.10 Soft ferrites . . . . . . . . . . . . . . . . . . . . 312 4.3 Hard Magnetic Materials . . . . . . . . . . . . . . . . 315 4.3.1 Hard magnetic material characterizing quantities . . . . . . . . . . . . . . . . . . . . . 315 4.3.1.1 Remanent magnetization. . . . . 316 4.3.1.2 Saturation magnetization . . . . 316 4.3.1.3 Coercivity . . . . . . . . . . . . . . 316 4.3.1.4 The maximum energy product . . . . . . . . . . . . . . . . 316 4.3.1.5 Squareness coefficient . . . . . . . 318 4.3.1.6 Orientation coefficient . . . . . . 320 4.3.1.7 Recoil curves and maximum working field . . . . . . . . . . . . 320 4.3.1.8 The Curie temperature and temperature coefficients . . . . . 321 4.4 Available Materials . . . . . . . . . . . . . . . . . . . . 322 4.4.1 Hard magnet classification . . . . . . . . . . 322 4.4.2 Alnico magnet alloys . . . . . . . . . . . . . . 327 4.4.3 Hard magnetic ferrites . . . . . . . . . . . . . 328 4.4.4 SmCo magnets . . . . . . . . . . . . . . . . . . 331 4.4.5 NdFeB magnets . . . . . . . . . . . . . . . . . 332 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335 Chapter 5. Characterization Methods 339 5.1 General Overview . . . . . . . . . . . . . . . . . . . . . 339 5.2 Material Characterization Approaches . . . . . . . . 343 5.2.1 Sheet characterization methods . . . . . . . 345 5.2.2 Ring core measurements . . . . . . . . . . . 347