High piezoelectricity in low-temperature sintering potassium–sodium niobate-based lead-free ceramics

Effect of CaZrO3 on phase structure and electrical properties of KNN-based lead-free ceramics

“…Therefore, there is a great need to develop lead free piezoelectric ceramics with good piezoelectric properties for replacing the lead-based ceramics in various applications. [3][4][5] Many lead free ferroelectric materials such as barium titanate (BT), 6,7 potassium niobate(KN), 8 potassium sodium niobate(KNN), [9][10][11][12][13][14][15][16][17][18][19][20][21] potassium tantalate niobate(KTN) [22][23][24][25] and bismuth sodium titanate(BNT), [26][27][28] have been investigated. Among all the lead free materials, K 0.5 Na 0.5 NbO 3 (KNN), the solid solution of ferroelectric KNbO 3 and antiferroelectric NaNbO 3 , has been studied extensively, considered one of the most promising candidates for lead-free piezoelectric ceramics for its high Curie temperature, outstanding piezoelectric and ferroelectric properties, and large electromechanical coupling coefficients as well as its better environmental compatibility than other lead-free piezoelectric ceramics, which superior piezoelectric attribute to orthorhombic-tetragonal polymorphic phase transition(PPT) around room temperature, and considered to be closely associated with phase coexistence in a way similar to that morphotropic phase boundary (MPB)-a phase boundary that a narrow composition region with orthorhombic or monoclinic phase separating rhombohedral and tetragonal phases in solid solutions-for widely used PZT-based ceramics.…”

Revealing the role of cationic displacement in potassium–sodium niobate lead-free piezoceramics by adding W6+ ions

“…Among the available lead-free ferroelectric ceramics, one promising candidate is the family of sodium potassium niobate (K,Na)NbO 3 (KNN), on account of its good electromechanical properties [3][4][5] . As for PZT, the sinterability of KNN-based materials can be improved by using different sintering aids and dopants [6][7][8][9] .…”

Balanced Development of Piezoelectricity and Curie Temperature in KNN-BC-xBNH Lead-Free Ceramics

“…5 In the past few years, potassium-sodium niobate (K,Na)NbO 3 (KNN) has been regarded as a potential candidate to replace lead-based piezoelectric materials because of its good electrical properties and a high Curie temperature (T c ). [6][7][8][9][10][11][12][13] However, the polymorphic phase transition (PPT) in KNN-based materials is different from the morphotropic phase boundaries (MPB) in PZT-based materials, and their electrical properties are related not only to composition but also to temperature. 14 16 More recently, some studies have shown that bismuth-based compounds substituted for PZT can simultaneously achieve good electrical properties and high Curie temperature.…”