Giant piezoelectricity, rhombohedral-orthorhombic-tetragonal phase coexistence and domain configurations of (K,Na)(Nb,Sb)O3–BiFeO3–(Bi, Na)ZrO3 ceramics

Emerging new phase boundary in potassium sodium-niobate based ceramics

“…72 In the same way, they also observed the R-O-T multi-phase coexistence in (0.994 À x)(K 0.40 Na 0.60 )(Nb 0.955 Sb 0.045 )O 3 -0.006BiFeO 3 -x(Bi 0.50 Na 0.50 )ZrO 3 (x = 0.01-0.04). 73 Secondly, the diffused T R-O may also manifest the existence of the R phase. As we know, the phase transitions of piezoceramics are gradual, not as rapid as in single crystals due to the grain size distribution and intragranular stresses.…”

“…24,25 More importantly, other groups not only constructed the NPB successfully, but also achieved enhanced performance (including d 33 values and strain temperature stability). 73,86,212,[221][222][223][224][225][226][227][228] For example, Zhang et al successfully constructed the NPB and even obtained higher d 33 values (e.g., 512 pC N À1 ) than our previously reported ones (e.g., 419-450 pC N À1 ), using the same additives (e.g., Sb 5+ , (Bi 0.5 Na 0.5 )ZrO 3 and (Bi 0.5 Na 0.5 )HfO 3 ), as marked by the red dashed line. 45,54,68,69,104 [221][222][223]226,227 More interestingly, Zhai et al achieved an ultra-high d 33 value of 700 pC N À1 in highly textured KNN-3T ceramics.…”

The Role of Adding Bi0.5A0.5ZrO3 in Affecting Orthorhombic-Tetragonal Phase Transition Temperature and Electrical Properties in Potassium Sodium Niobate Ceramics

“…Generally, an O phase has distinct {200}pc diffraction peaks, that is, the intensity of (202)O peak is twice higher than that of (020)O peak [27]. Therefore, all KNN-Zr ceramics possess an O phase at room temperature, irrespective of the content of Zr (Figure 1 To further reveal the alone effects of Zr4+ and Bi3+ on the phase structure, we fitted the XRD patterns in Figures 1(c, f) by using the Lorentz fitting and quantified their variations (Figures 2(a-h)) [30]. With increasing Zr4+ and Bi3+, 2θ of (202)O (abbreviated as 2θ202) slightly increases, and 2θ of (020)O (abbreviated as 2θ020) rapidly decreases, indicating the accelerated shifting between (202)O and (020)O peaks towards each other.…”

“…However, their synergetic effects are valid within a certain content because of the gradually destroyed LRO induced by the aliovalent substitutions [21,34]. Therefore, the ferroelectric-relaxor phase transition has been observed when the content of Bi0.5A0.5ZrO3 exceeded 5~6 molar percentage, and the relaxors have a PC phase and a single {200}pc diffraction peak [28][29][30]51]. Similarly, the ferroelectric-relaxor phase transition has also been reported in MZrO3-doped (K0.5Na0.5)NbO3 ceramics (M = Ba, Sr, and Ca) because of the aliovalent substitutions on both A-and B-sites [48,55].…”

Enhanced thermal and cycling reliabilities in (K,Na)(Nb,Sb)O3-CaZrO3-(Bi,Na)HfO3 ceramics

“…In particular, Xu et al [10] successfully fabricated non-textured KNN-based lead-free ceramics with ultrahigh piezoelectric property (d 33 ≈ 570 pC/N) by construction of rhombohedral-tetragonal (R-T) phase boundary at room temperature. Besides, the superior piezoelectric properties with d 33 ≈ 550 pC/N were achieved in KNN-based ceramics by adjusting phase structure and domain configurations [11,12]. However, inferior thermal stability and fatigue resistance of KNN-based ceramics tremendously restrain their industrialized application [13][14][15].…”