Provides in-depth knowledge on lead-free piezoelectrics - for state-of-the-art, environmentally friendly electrical and electronic devices!
Lead zirconate titanate ceramics have been market-dominating due to their excellent properties and flexibility in terms of compositional modifications. Driven by the Restriction of Hazardous Substances Directive, there is a growing concern on the toxicity of lead. Therefore, numerous research efforts were devoted to lead-free piezoelectrics from the beginning of this century. Great progress has been made in the development of high-performance lead-free piezoelectric ceramics which are already used, e.g., for power electronics applications.
Lead-Free Piezoelectric Materials provides an in-depth overview of principles, material systems, and applications of lead-free piezoelectric materials. It starts with the fundamentals of piezoelectricity and lead-free piezoelectrics. Then it discusses four representative lead-free piezoelectric material systems from background introduction to crystal structures and properties. Finally, it presents several applications of lead-free piezoelectrics including piezoelectric actuators, and transducers. The challenges for promoting applications will also be discussed.
- Highly attractive: Lead-free piezoelectrics address the growing concerns on exclusion of hazardous substances used in electrical and electronic devices in order to protect human health and the environment
- Thorough overview: Covers fundamentals, different classes of materials, processing and applications
- Unique: discusses fundamentals and recent advancements in the field of lead-free piezoelectrics
Lead-Free Piezoelectric Materials is of high interest for material scientists, electrical and chemical engineers, solid state chemists and physicists in academia and industry.
Table of Contents
About the Author ix
Foreword by Professor Longtu Li xi
Foreword by Professor Jürgen Rödel xiii
Preface xv
1 Fundamentals of Piezoelectricity 1
1.1 Introduction 1
1.2 Piezoelectric Effects and Related Equations 2
1.3 Ferroelectric Properties and Its Contribution to Piezoelectricity 3
1.4 Piezoelectric Parameters 7
1.4.1 Piezoelectric Constants 7
1.4.1.1 Piezoelectric Charge (Strain) Constant 7
1.4.1.2 Piezoelectric Voltage Coefficient (G-constant) 8
1.4.2 Piezoelectric Coupling Coefficient 8
1.4.3 Mechanical Quality Factor 9
1.5 Issues for Measuring Piezoelectric Properties 10
1.5.1 Measurement of Direct Piezoelectric Coefficient Using the Berlincourt Method 10
1.5.2 Measurement of Converse Piezoelectric Coefficient by Laser Interferometer 12
1.5.3 Resonance and Anti-resonance Method 14
References 16
2 High-Performance Lead-Free Piezoelectrics 19
2.1 Introduction 19
2.2 BaTiO3 21
2.3 (K,Na)NbO3 23
2.4 (Bi1/2Na1/2)TiO3 25
2.5 BiFeO3 27
2.6 Summary 28
References 28
3 (K,Na)NbO3 System 33
3.1 Introduction of (K,Na)NbO3 33
3.1.1 History of (K,Na)NbO3 33
3.1.2 Crystal Structure and Phase Diagram 33
3.1.3 Current Development of KNN-Based Materials 36
3.2 Synthesis 37
3.2.1 Calcination 37
3.2.2 Sintering 38
3.2.2.1 Normal Sintering 39
3.2.2.2 Hot Pressing, Spark Plasma Sintering, and Microwave Sintering 41
3.2.3 Texturing 43
3.3 Approaches to Piezoelectricity Enhancement 44
3.3.1 Phase Engineering 45
3.3.1.1 O-T Phase Boundary 45
3.3.1.2 R-T Phase Boundary 47
3.3.2 Thermal Stability 49
3.3.3 Multiscale Heterogeneity 53
3.3.4 Poling Techniques 57
3.4 Fatigue and Mechanical Properties 57
3.4.1 Fatigue 57
3.4.2 Mechanical Properties 60
3.5 KNN Thin Films 62
3.5.1 Sol-Gel-Processed Films 63
3.5.2 KNN Films Prepared by Physical Methods 65
3.6 Single Crystals 67
3.7 Summary 68
References 69
4 (Bi1/2Na1/2)TiO3 System 85
4.1 Introduction of BNT System 85
4.2 Extensive Research on Phase Diagram of (Bi1/2Na1/2)TiO3 -BaTiO3 System 86
4.2.1 Relaxor or Antiferroelectric? 86
4.2.2 MPB and Complex Phase Structure 90
4.3 High Converse Piezoelectricity 93
4.3.1 Electric-Field-Induced Phase Transition 95
4.3.2 Ergodic and Nonergodic Relaxor 98
4.3.3 Modulation of Depolarization Temperature 103
4.3.3.1 Compositional Modification Approach 103
4.3.3.2 Composite Approach 104
4.3.3.3 Stress Approach 105
4.4 Thin Films 106
4.5 Single Crystals 109
4.6 High-Power Application 110
4.7 Summary and Outlook 112
References 112
5 BaTiO3 System 123
5.1 Brief Introduction of History 123
5.2 BaTiO3-Based Ceramics and Single Crystals 125
5.2.1 Ceramics 125
5.2.2 Single Crystal 128
5.3 BaTiO3-Based Solid Solution Ceramics 129
5.3.1 (Ba,Ca)(Ti,Zr)O3 130
5.3.2 (Ba,Ca)(Ti,Sn)O3 132
5.3.3 (Ba,Ca)(Ti,Hf)O3 134
5.4 Piezoelectricity Enhancement 135
5.4.1 Phase Engineering 135
5.4.2 Domain Engineering 137
5.4.3 Texturing 139
5.5 Key Issues of Sintering Processes 139
5.5.1 Li-containing Sintering Additives 140
5.5.2 Glass Compositions 141
5.6 Mechanical Property 142
5.7 Summary and Outlook 144
References 145
6 BiFeO3 System 157
6.1 Introduction 157
6.2 Brief Introduction to Multiferroic Materials 157
6.3 Multiferroicity of BiFeO3 159
6.3.1 Ferroelectricity 159
6.3.2 Antiferromagnetism and Weak Ferromagnetism 159
6.3.3 Magnetoelectric Coupling 161
6.3.3.1 Antiferromagnetic Switching on Electric Field 161
6.3.3.2 Ferroelectricity on Magnetic Field 162
6.4 Phase Diagram of BiFeO3 163
6.4.1 High Curie Temperature and Processing Issues 163
6.4.2 Influence of Pressure on Phase Diagram 165
6.4.3 Thin Film and Strain Effect on Phase Structure 166
6.5 Dielectric Permittivity, Electrical Conductivity, and Domain Wall Conductivity of BiFeO3 169
6.5.1 Dielectric Permittivity 169
6.5.2 Electrical Conductivity and Defects 170
6.5.3 Domain Wall Conductivity 172
6.6 Ion Substitutions in BiFeO3 174
6.6.1 On Ferroelectricity (Pr) and Piezoelectricity (d33) 175
6.6.2 On Phase Transformation 177
6.6.3 On Magnetic Properties 177
6.7 BiFeO3-Based Solid Solutions 178
6.7.1 BiFeO3-BaTiO3 178
6.7.2 Other Solid Solutions 180
6.8 Application of BiFeO3: Potentials and Status 180
6.8.1 Ferroelectricity and Electronics 181
6.8.2 Magnetoelectric Coupling and Spintronics 182
6.8.3 Domain Wall Based Electronics 184
6.9 Summary 184
References 185
7 Applications 197
7.1 Introduction 197
7.2 Representative Applications of Lead-Free Piezoelectric Ceramics 199
7.2.1 Piezoelectric Multilayer Actuators 199
7.2.2 KNN-Based Actuation Structure in Inkjet Printhead 201
7.2.3 Ultrasonic Transducers 202
7.2.4 KNN-Based Knocking Sensors 205
7.3 Other Potential Applications 206
7.3.1 Energy Harvesting 206
7.3.2 High-Frequency Medical Imaging Transducers Using 1-3 Composites 208
7.3.3 High-Temperature Piezoelectrics and Applications 210
7.4 Summary and Outlooks 210
References 211
Index 217
