Phase boundary, poling conditions, and piezoelectric activity and their relationships in (K_0.42Na_0.58)(Nb_0.96Sb_0.04)O₃–(Bi_0.5K_0.5)_0.90Zn_0.10ZrO₃lead-free ceramics

Structure, dielectric, and piezoelectric properties of K0.5Na0.5NbO3-based lead-free ceramics

“…6,8,[10][11][12][13] Recently, a number of manpower and nancial resources are invested into the study of KNN-based piezoelectrics, and some signicant developments have been achieved. [9][10][11][12][13][14][15][16][17][18] KNN is a solid solution of ferroelectric compound KNbO 3 having space group Cm2m and antiferroelectric NaNbO 3 having space group Pbma with an orthorhombic perovskite structure at room temperature. 16 The composition near x ¼ 0.5 is of the great interest because of the superior ferroelectric and piezoelectric properties.…”

Modification of strain and piezoelectricity in (K,Na)NbO3–(Bi,Na)HfO3 lead-free ceramics with high Curie temperature

“…As seen in it, the d 33 rises first and then drops with the changed temperatures from 10 C to 140 C, reaching a peak value of~385 pC/N at 40 C. The previous studies show that the phase boundary is one of the most important reasons for enhancing d 33. [3,16,17]. Fig.…”

“…As known to all, d 33 of the ceramics is related to not only the compositions but also polarization conditions (e.g., poling temperatures, poling electric fields, and dwell time) [3,16,17]. For KNN ceramics, the poling temperature (T p ) becomes very important due to the intrinsic characteristics of OeT phase boundary with a PPT [3,16,17]. Therefore, we plot the curves of d 33 and k p against T p in the ceramics with x ¼ 0.05, as shown in the inset of Fig.…”

“…In the past, we have observed a high d 33 (~419 pC/N) in (1-x) K 0.45 Na 0.55 Nb 0.96 Sb 0.04 O 3 exBi 0.5 Na 0.5 HfO 3 ceramics [21], and unfortunately a low T C (~242 C) can be only attained due to the involvement of antimony [3,17]. In addition, antimony (Sb) is considered as toxic material.…”

Simultaneous realization of high transparency and piezoelectricity in low symmetry KNN‐based ceramics

“…The d 33 value was measured at room temperature after annealing for 2 hours at a chosen temperature. When T a goes up to 100°C, the d 33 value declines slightly from 101 to 88 pC/N due to the presence of O phase; then d 33 drops dramatically across the suppressed O‐T phase boundary in the tetragonal phase zone . At last, the d 33 value reduces gradually culminating in a significant drop as T a is close to the Curie temperature (~280°C).…”