Rhombohedral-Tetragonal Phase Coexistence and Piezoelectric Properties of (NaK)(NbSb)O3-LiTaO3-BaZrO3 Lead-Free Ceramics

Abstract

The phase transitional behavior and composition‐dependent piezoelectric properties of (NaK)(NbSb)O3–LiTaO3–BaZrO3 (NKNS–LT–BZ) pseudo‐ternary system were investigated. A composition–temperature phase diagram was generalized within a certain range of BZ content in which a rhombohedral–tetragonal (R–T ) ferroelectric phase boundary connecting orthorhombic and cubic phase zones is formed near room temperature between two trifurcate points. Piezoelectric and electromechanical properties of NKNS–LT–BZ ceramics exhibit optimum values of d33=365 pC/N and kp=45% in the vicinity of the R–T phase coexistence zone. The dielectric and ferroelectric properties and the phase transition of NKNS–LT–BZ ceramics were discussed from a crystallographic point of view.

Enhanced bipolar fatigue resistance in CaZrO3-modified (K,Na)NbO3 lead-free piezoceramics

“…It is therefore reasonable to conclude that CZ0 ceramics are highly susceptible to bipolar cycling by the time of the 10 7 cycles. However, there is also no discernable degradation of various properties for CZ5 when cycles were within 10 6 . In other words, the CZ5 ceramics are insensitive to electric cycling during the initial cycling stages.…”

“…Consequently, it has triggered worldwide interest, [1][2][3][4] through which significant resources were devoted to strengthening their piezoelectricity through compositional optimization or domain engineering. [5][6][7][8][9] However, the essential requirements enabling piezoceramics to be appropriate for applications comprise not only reproducibly outstanding piezoelectric properties but also long term stability of these properties, e.g., good fatigue resistance. 10 Bipolar piezoelectric fatigue is manifested by the loss of switchable polarization and the decrease of strain and piezoelectric coefficient of piezoceramics after being exposed to millions of electric field cycles.…”

Development of KNN-Based Piezoelectric Materials

“…A large number of dopants on both A and B sites as well as different solid solutions are studied in order to improve the piezoelectric properties of KNN [67][68][69][70][71][72][73][74][75][76][77][78][79]. To understand the structure -property correlation in KNN-based ceramics Ahn et al studied the interdependence of piezoelectric coefficient d 33 , tetragonal to orthorhombic transition temperature (T oÀt ) and fraction of tetragonality [80].…”

(K,Na)NbO3-based Lead-free Piezoelectric Materials: An Encounter with Scanning Probe Microscopy

“…As a result, designing a PZT-like MPB in KNN systems seems more practical. The success of constructing a tricritical triple point in BaTiO 3 system [74,75], as well as similar attempt in KNN-based ceramics [54], could probably offer fresh and innovative ideas for the future.…”

“…As a result, the development of KNN-based ceramics is retarded for the time being, the situation of which has been encountered before by many great scientific innovations. Fortunately, several tentative ideas have already been brought out to further exploiting the potential of KNN-based materials as next generation lead-free piezoceramics [52][53][54].…”