Piezoelectric properties of (K0.5Na0.5)(Nb1−xTax)O3−K5.4CuTa10O29 ceramics

Abstract

( K 0.5 Na 0.5 ) ( Nb 1 − x Ta x ) O 3 ( K N N T ) -based ceramics have been synthesized via a solid-state reaction. In this study, KNNT-based ceramics were sintered at atmospheric pressure by adding small amounts of sintering aid [ 0.38 mol % K 5.4 Cu 1.3 Ta 10 O 29 ]. The ( K 0.5 Na 0.5 ) Nb O 3 (KNN) ceramics which synthesized by using the K 5.4 Cu 1.3 Ta 10 O 29 showed “hard” piezoelectriccharacteristics such as a high mechanical quality factor ( Q m = 1300 ) and low tan δ (0.4%). The quantitative effects of Ta on the electrical properties of ( K 0.5 Na 0.5 ) ( Nb 1 − x Ta x ) O 3 – K 5.4 Cu 1.3 Ta 10 O 29 ceramics were also examined. Ta substitution provides “soft” piezoelectriccharacteristics and a large electrostrictive effect for KNN, which resulted in an improvement in k p , ε r , strain, and d 33 of KNNT ceramics depending upon the Ta content. Especially, ( K 0.5 Na 0.5 ) ( Nb 0.7 Ta 0.3 ) O 3 showed the maximum strain and d 33 values of 0.11% (at 40 kV ∕ cm ) and 270 pm ∕ V (at 30 – 40 kV ∕ cm ), respectively. This strain level is comparable to that of hard Pb ( Zr , Ti ) O 3 ceramics.