Title Page

Abstract

Contents

Motivation 33

1. Introduction 35

1.1. General background: Piezoelectric ceramics 35

1.1.1. Historical introduction of piezoelectricity 35

1.1.2. Principles of piezoelectric materials 37

1.1.3. Perovskite ferroelectrics 41

1.1.4. Piezoelectric lead zirconate titanate (PZT) system 44

1.1.5. The phase diagram of Pb(Zr,Ti)O₃ system 46

1.1.6. The terminology of piezoceramics: Definitions, symbols and notations 49

1.1.7. Curie temperature (Tc)(이미지참조) 59

1.1.8. Dielectric hysteresis 59

1.1.9. Ferroelectric domains 62

1.1.10. Piezoelectric poling 64

1.1.11. Current approach to improve piezoelectric properties of PZT 66

1.2. Introduction to piezoelectric energy harvesting 75

1.2.1. Energy harvesting 75

1.2.2. Necessity of energy harvesting 76

1.2.3. Available energy sources 78

1.2.4. Vibration energy harvesting techniques 80

1.2.5. Electrostatic (capacitive) power conversion 81

1.2.6. Electromagnetic (inductive) power conversion 82

1.2.7. Piezoelectric generator to harvest energy from vibration 82

1.2.8. Principal of piezoelectric conversion 85

1.2.9. Types of vibrations considered 89

1.2.10. Selection of piezoelectric materials for energy harvesting 91

1.3. Literature review and dissertation objectives 95

1.3.1. Literature review and current approach: Vibration energy harvesting using piezoelectric materials 95

1.3.2. Specific dissertation objectives 100

2. Experimental procedure 103

2.1. Bulk ceramic processing 103

2.1.1. Fabrication of (1-x)PZT-xBiYO₃ by conventional ball milling process 106

2.1.2. Fabrication of 0.99PZT-0.01BiYO₃ by HEM process 107

2.1.3. Fabrication of 0.99PZT-0.01Bi[Y1-xFex]O₃ by conventional ball milling process(이미지참조) 109

2.1.4. Fabrication of (1-x)PZT-xBi[Y0.7Fe0.3]O₃ by conventional ball milling process(이미지참조) 109

2.1.5. Fabrication of 0.99PZT-0.01Bi[Y1-xSbx]O₃ by conventional ball milling process(이미지참조) 110

2.2. Sintering 110

2.3. Poling 113

2.4. Basic characterization 113

2.4.1. Density 113

2.4.2. Piezoelectric and dielectric properties measurement 114

2.5. X-ray diffraction 116

2.6. Thermogravimetry and differential scanning calorimetry 117

2.7. Particle size analysis 117

2.8. Microstructure 117

2.9. Ferroelectric hysteresis loop 117

2.10. Electromechanical properties measurement under various alternating electric field 118

2.11. Piezoelectric displacement measurement 118

3. Results and discussion 121

3.1. Phase-formation, microstructure, and piezoelectric/dielectric properties of BiYO₃ and Pb(Zr0.53Ti0.47)O₃ solid solution for piezoelectric energy harvesting devices(이미지참조) 121

3.1.1. Synopsis 121

3.1.2. Effects of pre-synthesized BiYO₃ doping on the crystal structure and microstructure 122

3.1.3. Effects of pre-synthesized BiYO₃ doping on the piezoelectric and the dielectric properties 129

3.1.4. Chapter summary 147

3.2. Effect of high energy milling process on microstructure and piezoelectric/dielectric properties of 0.99Pb(Zr0.53Ti0.47)O₃-0.01BiYO₃ ceramic for piezoelectric energy harvesting devices(이미지참조) 148

3.2.1. Synopsis 148

3.2.2. Effects of nano-sized particles on the reaction temperature 149

3.2.3. Effects of the nano-sized PZT-BY powder on the microstructure and the piezoelectric/ dielectric properties 153

3.2.4. Chapter summary 164

3.3. Effects of Fe₂O₃ addition on the piezoelectric and the dielectric properties of 0.99Pb(Zr0.53Ti0.47)O₃-0.01Bi(Y1-xFex)O₃ ceramics for energy harvesting devices(이미지참조) 165

3.3.1. Synopsis 165

3.3.2. Phase analysis of pre-synthesized PZT and Bi[Y(1-x)Fex]O₃(이미지참조) 166

3.3.3. Crystal structure and microstructural change of PZT-BYF(x) due to the addition of Fe₂O₃ 168

3.3.4. Effect of Fe₂O₃ addition on the piezoelectric and the dielectric properties of PZT-BYF(x) ceramics 181

3.3.5. Ferroelectric properties of Fe₂O₃-doped PZT-BYF(x) ceramics 185

3.3.6. Temperature dependence of the relative dielectric constant 187

3.3.7. Evaluation of the energy harvesting parameters for the PZT-BYF(x) system 190

3.3.8. Chapter summary 196

3.4. Piezoelectric materials of (1-x)Pb(Zr0.53Ti0.47)O₃-xBi(Y0.7Fe0.3)O₃ for energy harvesting devices.(이미지참조) 198

3.4.1. Synopsis 198

3.4.2. Phase analysis of pre-synthesized Pb(Zr0.53Ti0.47)O₃ and Bi(Y0.7Fe0.3)O₃(이미지참조) 199

3.4.3. Effects of pre-synthesized BYF content on the microstructure and the densities of (1-x)PZT-xBYF ceramics 201

3.4.4. Effects of pre-synthesized BYF doping on the crystal structure and microstructure at optimum sintering temperature 205

3.4.5. Effects of pre-synthesized Bi(Y0.7Fe0.3)O₃ doping on the piezoelectric and the dielectric properties of (1-x)PZT-xBYF ceramics at optimum sintering temperature(이미지참조) 210

3.4.6. Effects of BYF content of (1-x)PZT-xBYF ceramics on the energy harvesting parameters 220

3.4.7. Chapter summary 225

3.5. Fabrication of Sb₂O₃ doped 0.99Pb(Zr0.53Ti0.47)O₃-0.01Bi(Y1-xSbx)O₃ ceramics for high energy density piezoelectric materials(이미지참조) 226

3.5.1. Synopsis 226

3.5.2. Phase analysis of pre-synthesized PZT and Bi[Y(1-x)Sbx]O₃(이미지참조) 227

3.5.3. Comparative study of Sb₂O₃ and Sb2O5 doping on PZT-BY system(이미지참조) 230

3.5.4. Effects of pre-synthesized BYS content on the densities of PZT-BYS(x) ceramics 234

3.5.5. Effects of pre-synthesized BYS(x) on the crystal structure and microstructure 236

3.5.6. Effects of Sb₂O₃ doping on the piezoelectric and the dielectric properties of PZT-BYS(x) ceramics at optimum sintering temperature 243

3.5.7. Effects of Sb₂O₃ content of PZT-BYS(x) ceramics on the energy harvesting parameters 252

3.5.8. Chapter summary 256

4. General summary 258

5. Conclusions 265

References 271

List of publications 293

Table 1.1. Properties of lead zirconate titanate ceramics 45

Table 1.2. Comparison of the characteristics of soft and hard... 70

Table 1.3. The energy sources commonly available in the environment. 79

Table 1.4. Comparison of different conversion techniques. 84

Table 1.5. List of vibration sources with their maximum acceleration... 90

Table 1.6. Typical properties of some commercially available piezoelectric materials 93

Table 2.1. Component oxides used in this study. 105

Table 3.1.1. The comparative parameters of PZT-BY(0.01) obtained... 140

Table 3.1.2. Calculated values of g₃₃ and (d₃₃ × g₃₃) at different moles... 141

Table 3.1.3. Longitudinal and transverse piezoelectric coefficients and... 145

Table 3.1.4. Properties of some PZT based energy harvesting materials 146

Table 3.2.1. The comparative parameters of PZT-BY obtained with... 157

Table 3.3.1. c/a ratio of Fe₂O₃ doped PZT-BYF(x) ceramics sintered at... 173

Table 3.3.2. Ferroelectric, dielectric and piezoelectric characteristics of the PZT-BYF(x) ceramics... 184

Table 3.3.3. Calculated value of g₃₃ and (d₃₃ × g₃₃) for PZT-BYF... 193

Table 3.3.4. A comparison between present work and recently reported piezoelectric ceramic materials for... 195

Table 3.4.1. The density, piezoelectric/dielectric and energy harvesting properties of (1-x)PZT-xBYF... 203

Table 3.4.2. Ferroelectric, dielectric and piezoelectric properties of the (1-x)PZT-xBYF ceramics at... 214

Table 3.4.3. The calculated value of g₃₃and (d₃₃ × g₃₃) for (1-x)PZT-xBYF ceramics as a function of BYF... 223

Table 3.4.4. A comparison between present work and recently reported piezoelectric ceramic materials for... 224

Table 3.5.1. The piezoelectric, dielectric and energy harvesting parameters of Sb₂O₃ and Sb2O5 doped PZT-...(이미지참조) 233

Table 3.5.2. Calculated lattice parameters of PZT-BYS(x) samples. 238

Table 3.5.3. The ferroelectric, dielectric and piezoelectric properties of the PZT-BYS(x) ceramics at... 251

Table 3.5.4. Calculated value of g₃₃ and (d₃₃ × g₃₃) for PZT-BYS(x) ceramics as a function of Sb₂O₃ content... 254

Table 3.5.5. A comparison between present work and recently reported piezoelectric ceramic materials for... 255

Table 4.1. Selected compositions with maximum g₃₃ and (d₃₃ × g₃₃). 260

Table 4.2. Transverse piezoelectric coefficients and their corresponding energy densitys. 264

Fig. 1.1. Tree diagram of 20 non-centrosymmetric point group belonging... 39

Fig. 1.2. Schematic representation of the crystalline structure and... 40

Fig. 1.3. Schematic representation of the ideal perovskite structure(ABO₃). 43

Fig. 1.4. Phase diagram of lead zirconate titanate (PZT) 48

Fig. 1.5. Designation of the direction. The direction of positive... 51

Fig. 1.6. A typical impedance curve of the equivalent circuit for... 56

Fig. 1.7. A typical hysteresis loop showing remnant polarization (Pr),...(이미지참조) 61

Fig. 1.8. Illustration of the formation of 180˚ and 90˚ ferroelectric domain... 63

Fig. 1.9. Poling process in piezoelectric ceramics 65

Fig. 1.10. Effects of doping in PZT system 68

Fig. 1.11. A photograph of a high energy milling equipment. 74

Fig. 1.12. Circuit representation of a piezoelectric element. 87

Fig. 1.13. Schematic representation of the components of a piezoelectric... 88

Fig. 2.1. Processing block diagram for PZT-BY(x) preparation (process I:... 108

Fig. 2.2. Photos of enclosed alumina crucible method for the sintering of... 112

Fig. 2.3. An experimental set-up for displacement measurement 120

Fig. 3.1.1. XRD patterns of (a) BiYO₃ (b) Pb(Zr0.53Ti0.47)O₃ powders...(이미지참조) 124

Fig. 3.1.2. (a) XRD multi plot patterns of PZT-BY(x) (0≤ x≤0.05) system... 125

Fig. 3.1.3. SEM images of fracture surface of PZT-BY(x) (0≤x≤0.05)... 126

Fig. 3.1.4. Density of PZT-BY(x) ceramics sintered at 1,160 ℃ for 2 h... 128

Fig. 3.1.5. Variation of piezoelectric and dielectric properties as a function... 131

Fig. 3.1.6. The temperature dependence of relative dielectric constant for... 135

Fig. 3.1.7. (a) Room temperature P-E hysteresis of PZT-BY(x) ternary... 136

Fig. 3.1.8. SEM images of fracture surface of PZT-BY(0.01) prepared by... 139

Fig. 3.1.9. Variations of the g₃₃ and (d₃₃ × g₃₃) values of PZT-BY(x)... 144

Fig. 3.2.1. SEM micrographs of high energy milled and conventional ball... 151

Fig. 3.2.2. X-ray diffraction patterns of calcined powders (a) BY and (b)... 152

Fig. 3.2.3. SEM micrographs of nano-sized PZT-BY sintered at (a)... 155

Fig. 3.2.4. Variations of sintered density as a function of temperature. The... 156

Fig. 3.2.5. Variation of piezoelectric and dielectric properties as a function... 159

Fig. 3.2.6. Room temperature P-E curves for nano-sized PZT-BY and... 161

Fig. 3.2.7. Variations of the g₃₃ and (d₃₃ × g₃₃) values of nano PZT-BY... 163

Fig. 3.3.1. X-ray diffraction patterns of (a) Bi[Y(1-x)Fex]O₃ [BYF(x)]...(이미지참조) 167

Fig. 3.3.2. (a) X-ray diffraction patterns of Fe₂O₃ doped PZT-BYF(x)... 169

Fig. 3.3.3. Variations of lattice constant ratio (c/a) as a function of... 172

Fig. 3.3.4. SEM images of fracture surface of Fe₂O₃ doped PZT-BYF(x)... 176

Fig. 3.3.5. SEM images of sintered surface of Fe₂O₃ doped PZT-BYF(x)... 177

Fig. 3.3.6. Differential scanning calorimetry and thermogravimetric... 178

Fig. 3.3.7. Density of PZT-BYF(x) specimens for various amounts of... 180

Fig. 3.3.8. Variations of piezoelectric and dielectric properties of PZT-... 183

Fig. 3.3.9. (a) P-E hysteresis curves for PZT-BYF(x) ceramics sintered at... 186

Fig. 3.3.10. Dielectric constant as a function of temperature and different... 189

Fig. 3.3.11. Effect of Fe₂O₃ addition on the piezoelectric voltage constant... 192

Fig. 3.4.1. X-ray diffraction patterns of (a) Pb(Zr0.53Ti0.47)O₃ calcined at...(이미지참조) 200

Fig. 3.4.2. SEM images of fracture surface of BYF doped (1-x)PZT-xBYF... 202

Fig. 3.4.3. Density of (1-x)PZT-xBYF specimens with various amounts of... 204

Fig. 3.4.4. (a) XRD patterns of BYF doped (1-x)PZT-xBYF... 208

Fig. 3.4.5. SEM images of fracture surface of (1-x)PZT-xBYF... 209

Fig. 3.4.6. Variation of piezoelectric and dielectric properties of (1-... 213

Fig. 3.4.7. (a) P-E hysteresis of (1-x)PZT-xBYF ceramics sintered at... 216

Fig. 3.4.8. Temperature dependence of dielectric constant for different... 219

Fig. 3.4.9. Effect of BYF addition on g₃₃ and (d₃₃ × g₃₃) for (1-x)PZT-... 222

Fig. 3.5.1. X-ray diffraction patterns of (a) Sb₂O₃ doped Bi[Y1-xSbx]O₃...(이미지참조) 229

Fig. 3.5.2. SEM images of the fracture surface of Sb₂O₃ and Sb2O5 doped...(이미지참조) 232

Fig. 3.5.3. Density of PZT-BYS(x) specimens with various amounts of... 235

Fig. 3.5.4. (a) X-ray diffraction patterns of Sb₂O₃ doped PZT-BYS(x)... 237

Fig. 3.5.5. Dependence of c/a ratios on amount of Sb₂O₃ content in PZT... 239

Fig. 3.5.6. SEM images of fracture surface of Sb₂O₃ doped PZT-BYS... 242

Fig. 3.5.7. Variation of the piezoelectric and the dielectric properties of... 246

Fig. 3.5.8. Pr and Ec measured from their corresponding hysteresis loops...(이미지참조) 248

Fig. 3.5.9. Temperature dependence of dielectric constant for different... 250

Fig. 3.5.10. Effect of Sb₂O₃ addition on g₃₃ and (d₃₃ × g₃₃) for PZT-... 253

Fig. 4.1. (a) Plot of displacement as a function of applied voltage, and (b)... 261

Fig. 4.2. Frequency response analysis of PZT-BYF(0.2) specimen as a... 262