High-performance KNN-based piezoelectric ceramics for buzzer application

Abstract Piezoelectric ceramic materials are important components of piezoelectric buzzers, where the parameter of inverse piezoelectric coefficient ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi>d</mml:mi> <mml:mrow> <mml:mn>33</mml:mn> </mml:mrow> <mml:mo>∗</mml:mo> </mml:msubsup> </mml:mrow> </mml:math> ) plays a decisive role in the performance of the buzzer. Here, we report the manufacture and performance of a lead-free ceramic-based (0.96(K 0.5 Na 0.5 )(Nb 0.96 Sb 0.04 )O 3 –0.04(Bi 0.5 Na 0.5 )ZrO 3 –1 mol% Al 2 O 3 , abbreviated as KNNS-BNZ-1 mol% Al 2 O 3 ) piezoelectric buzzer and compare it with commercial (PbZr 0.5 Ti 0.5 O 3 , abbreviated as PZT) ceramics. Briefly, KNN-based ceramics have a typical perovskite structure and piezoelectric properties of d 33 = 480 pC/N, k p = 0.62 and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi>d</mml:mi> <mml:mrow> <mml:mn>33</mml:mn> </mml:mrow> <mml:mo>∗</mml:mo> </mml:msubsup> <mml:mo>=</mml:mo> <mml:mn>830</mml:mn> </mml:mrow> </mml:math> pm/V, compared to d 33 = 500 pC/N, k p = 0.6 and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msubsup> <mml:mi>d</mml:mi> <mml:mrow> <mml:mn>33</mml:mn> </mml:mrow> <mml:mo>∗</mml:mo> </mml:msubsup> <mml:mo>=</mml:mo> <mml:mn>918</mml:mn> </mml:mrow> </mml:math> pm/V of the commercial PZT-4 ceramics. Our results show that the KNNS-BNZ-1 mol% Al 2 O 3 ceramics have a similar sound pressure level performance over the testing frequency range to commercial PZT ceramics (which is even better in the 3–4 kHz range). These findings highlight the great application potential of KNN-based piezoelectric ceramics.