The effect of template morphologies on microstructure and properties of textured K<inf>0.5</inf>Na<inf>0.5</inf>NbO<inf>3</inf> ceramics by RTGG method

Abstract

Lead free textured K 0.5 Na 0.5 NbO 3 piezoelectric ceramics have been prepared by reactive-templated grain growth method by using NaNbO 3 with different morphologies as templates. The NaNbO 3 template particles with different edge length (10-20 μm) and thickness (0.5-2.5 μm) was synthesized through controlling Bi 1.5 Na x-1.5 Nb x O 3x+3 precursor's layer numbers x from 2 to 6 by two-step molten salt methods. The crystalline phases and microstructure of textured K 0.5 Na 0.5 NbO 3 were characterized by X-ray diffraction and scanning electron microscopy, respectively. It shows that all the K 0.5 Na 0.5 NbO 3 ceramics are orthorhombic perovskite structure with {0 0 l} orientation. By using the template particles with a ratio of edge length to thickness (l/h) =~10, the textured ceramics with optimized piezoelectric properties was prepared. The results indicate that the enhanced properties of textured ceramics are concerned with the template morphology.

Synthesis of [10Ῑ]‐Oriented (Na1−xKx)NbO3 Platelets by Using Hydrothermally Produced (K8−8xNa8x)Nb6O19·nH2O Precursor

“…Perovskite platelets have attracted increased interest because they can be used as seed crystals in template grain growth (TGG). BaTiO 3 platelets have been used to fabricate [001]‐textured Pb(Mg 1/3 Nb 2/3 )‐PbTiO 3 ceramics, while NaNbO 3 and KNbO 3 platelets have been used to produce textured (N 1− x K x )NbO 3 (NKN)‐based ceramics . Highly textured ceramics that are produced by the TGG process generally have high piezoelectric and dielectric properties similar to those of the single crystals.…”

“…BaTiO 3 platelets have been used to fabricate [001]-textured Pb(Mg 1/3 Nb 2/3 )-PbTiO 3 ceramics, [1][2][3][4][5][6][7][8] while NaNbO 3 and KNbO 3 platelets have been used to produce textured (N 1Àx K x )NbO 3 (NKN)-based ceramics. [9][10][11][12][13][14] Highly textured ceramics that are produced by the TGG process generally have high piezoelectric and dielectric properties similar to those of the single crystals. Moreover, perovskite platelets can be mixed with a polymer system for the synthesis of piezoelectric nanogenerators because they can be preferentially aligned within the polymer and produce highoutput electrical energy.…”