Dielectric and Piezoelectric Properties of KNbO₃–NaNbO₃–LiNbO₃–SrTiO₃ Ceramics

Abstract

For the purpose of the developing Pb-free piezoelectric ceramics, the dielectric and piezoelectric properties of two series of KNbO 3 -NaNbO 3 -LiNbO 3 -SrTiO 3 (KN-NN-LN-ST) perovskite ceramics, namely 0.47KN-0.47NN-(0:06 À x)LN-xST (0 x 0:06) and 0.45KN-0.45NN-(0:10 À y)LN-yST (0:02 y 0:10) were investigated as functions of composition. In both series, the orthorhombic perovskite phase formed at lower temperatures, and was transformed to tetragonal form and then cubic form with increasing temperature. The orthorhombic-tetragonal transition temperature (T ot ) and tetragonal-cubic transition temperature (Curie temperature, T c ) gradually shifted toward lower temperatures with increasing ST content. For the 0.47KN-0.47NN-(0:06 À x)LN-xST series, the T ot ¼ 100 C and T c ¼ 500 C for x ¼ 0, and the T ot ¼ À20 C and T c ¼ 220 C for x ¼ 0:06. For the 0.45KN-0.45NN-(0:10 À y)LN-yST series, T ot ¼ À30 C and T c ¼ 450 C for y ¼ 0:02, and T ot ¼ À60 C and T c ¼ 330 C for y ¼ 0:05. Among the ceramics obtained, the 0.45KN-0.45NN-0.06LN-0.04ST composition showed relatively good piezoelectric properties, k p ¼ 0:33 and d 33 ¼ 120 pC/N, which are comparable to those of Pb-free piezoelectric ceramics previously reported.

New Synthesis of Nanosized Niobium Oxides and Lithium Niobate Particles and Their Characterization by XPS Analysis

“…[2][3][4][5][6] LN particles were also studied for their photo-catalytic activity, 7 8 their strong non-linear optics properties, 9 and their high electro-optical coefficient. 10 The lithium niobate was then included in thin films, 11 12 gels, 13 or as microfillers.…”

Mitigation of thermal and fatigue behavior in K0.5Na0.5NbO3-based lead free piezoceramics

“…1 Recently, high piezoelectric coefficients d 33 Ͼ 200 pC/ N have been reported for modified KNN using LiNbO 3 ͑LN͒, LiSbO 3 ͑LS͒, LiTaO 3 ͑LT͒, BaTiO 3 , SrTiO 3 , etc., with the added advantage of improved processibility. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] However, the enhanced properties are the result of compositionally shifting the orthorhombic to tetragonal polymorphic phase transition ͑PPT͒ downward from ϳ200°C to near room temperature. [6][7][8]19 Associated with a PPT are strong temperature dependent properties and degradation associated with domain instability during thermal cycling between the two distinct different ferroelectric domain states, making them impractical for various applications.…”

Vertical morphotropic phase boundary in lead-free piezoelectric ceramics (K,Na,Li)NbO3–BaZrO3–(La,Na)TiO3 system

“…In particular, lead-free BaTiO 3 -based, (Bi,Na)TiO 3 -based, and (K,Na)NbO 3 -based piezoelectric ceramics have been considered as replacement candidates for the PZT ceramics. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] The BaTiO 3 -based, (Bi, Na)TiO 3 -based, and (K,Na)NbO 3 -based system ceramics have the same perovskite structure as the PZT, and the MPB compositions were also formed/discovered in those systems. In our early work, one of the lead-free piezoceramics with vertical MPB has been successfully developed by adjusting the MPB slope of (K 0:45 Na 0:5 Li 0:05 ÞNbO 3 -BaZrO 3 (KNLN-BZ) binary system using the rhombohedral (Bi,Na)TiO 3 (BNT) as a third component.…”