Piezoelectric Properties and Microstructure of (K,Na)NbO3– KTiNbO5 Composite Lead-Free Piezoelectric Ceramic

Abstract

We developed a (K,Na)NbO 3-based lead-free piezoelectric ceramic with a KTiNbO 5 system, (K 1−x Na x) 0.86 Ca 0.04 Li 0.02 Nb 0.85 O 3−δ-KTiNbO 5-BaZrO 3-Co 3 O 4-Fe 2 O 3-ZnO (KNN-NTK composite). This KNN-NTK composite exhibits a very dense microstructure, and k p = 0.52, ε 33 T /ε 0 = 1600, and d 33 = 252 pC/N. We found that a portion of the KTiNbO 5 converted into K 2 (Ti,Nb,Co,Zn) 6 O 13 and/or CoZnTiO 4. We were able to reproducibly prepare granulated powder of KNN-NTK in batches of 100 kg using a spray-dryer. In addition, we performed a detailed investigation of the microstructure of KNN-NTK composite. The results show that a tetragonal and an orthorhombic phase coexist in a main KNN phase over a wide range of 0.56 ≤ x ≤ 0.75. The granular nanodomains of the orthorhombic phase dispersed within the tetragonal matrix in the KNN phase. A maximum value of k p = 0.56 occurred for x = 0.56. The Na fraction x corresponding to maximum k p was also the minimum x required to generate the orthorhombic phase. We conclude that the KNN-NTK composite exhibits excellent piezoelectric properties because of the two-phase coexisting state. This gentle phase transition of KNN-NTK composite seems to be a relaxor, but the diffuseness degree γ = 1.07 suggests otherwise.

Electromechanical Performance of Biocompatible Piezoelectric Thin-Films

“…The present investigation aimed toward analyzing a computational model to determine the electromechanical characteristics of biocompatible thin films: AlN, BaTiO 3 , ZnO, PVDF, and KNN-NTK. The properties used in this study were derived from the COM-SOL material library primarily and were cross verified with the current literature for their accuracy [51][52][53][54][55]. For PMN-PT (PMN-32% PT Type B), the piezoelectric properties were provided by CTS Corp The material properties of PVDF (50 nm with aluminum electrode) were obtained through the specifications as mentioned by the vendor PolyK Technologies, LLC, as the simulation model has been physically validated.…”

Influence of Double Calcination-Milling Route on the Structural and Microstructural Properties of Lead-Free K0.5NA0.5NBO3 (Knn) Ceramics

“…It is important to achieve higher density since the lower density material through single calcination would possess higher pores that decreases the chemical stability and mechanical strength of the material. The dielectric breakdown would also occur during polarization causes by the concentrated electric field at the excessive pores [21]. By using the double calcination route method, improved piezoelectric properties can be obtained due to the improvement of densification through the elimination of the porosity in the samples [22] shape and increased density, both of which potentially help to increase piezoelectric property.…”

Progress in Piezoelectric Material Based Oceanic Wave Energy Conversion Technology

“…In case of ceramic type piezoelectric devices such as barium titanate (BaTiO3) and AlN, plethora of small scale quartzes are arbitrarily oriented and under the application of electric potential exhibit piezoelectric properties [47], [84]. The lead-free piezoelectric composite ceramic (K,Na)NbO3-KTiNbO5 is developed and its characteristics are discussed in [85] along with the microstructure. Alkaline niobate ceramics (K,Na)NbO3 offer mainly improved microstructure piezoelectric properties and a comparatively high Curie temperature.…”