多维协同效应诱导的高压电性及可靠性的KNN压电陶瓷应用于高频超声换能器  

Multidimensional synergy-induced high piezoelectricity and reliability KNN piezoceramics for high-frequency ultrasonic transducers

作　　者：李睿琛 曾禹舜 孙茜茜 李崇阳 李润泽 郑婷 蒋来明 吴家刚 Ruichen Li;Yushun Zeng;Xi-xi Sun;Chongyang Li;Runze Li;Ting Zheng;Laiming Jiang;Jiagang Wu(Department of Materials Science,Sichuan University,Chengdu 610064,China;Department of Biomedical Engineering,Viterbi School of Engineering,University of Southern California,Los Angeles,CA 90089,USA)

机构地区：[1]Department of Materials Science,Sichuan University,Chengdu 610064,China [2]Department of Biomedical Engineering,Viterbi School of Engineering,University of Southern California,Los Angeles,CA 90089,USA

出　　处：《Science China Materials》2023年第2期686-695,共10页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China(NSFC 52202144,52061130216 and 52032007);the Key-Area Research and Development Program of Guangdong Province(2020B0109380001);the Central Funds Guiding the Local Science and Technology Development of Sichuan Province(2021ZYD0022);the Fundamental Research Funds for the Central Universities,Sichuan University(YJ2021153);the Newton Advanced Fellowship award(NAFR1201126)from the Royal Society。

摘　　要：高频超声换能器已成为现代医学诊断和治疗的有力工具.目前,大多数超声换能器使用压电陶瓷进行机电耦合,在高频(>20 MHz)下会发生周期性的电声转换,因此对材料可靠性要求较高.本文提出了一种结构调控策略,以提高铌酸钾钠(KNN)基无铅陶瓷的压电性与可靠性,并用于高频超声成像.该KNN基陶瓷具有增强的压电性(d33~550±20 pC N^(-1))及抗疲劳特性,同时针对其良好性能,我们从涉及宏观到微观的多项共存、完好微观结构与灵活畴翻转的多维度协同效应阐述其机理.该多维度协同效应抑制了疲劳过程中性能恶化裂纹的出现及空间电荷的聚集,从而减少了畴壁的钉扎,增强了抗疲劳性.此外,基于该高性能压电陶瓷制备的超声换能器具有高可靠性及温度稳定性(从室温到80℃,频带宽度几乎不变).我们利用该超声换能器扫描罗非鱼眼球结构测试了器件成像效果.相信通过结构策略实现性能提升的新方法可以促进KNN基超声器件在生物医学方面的应用.High-frequency ultrasonic transducers have been implemented as a powerful tool for modern medical diagnosis and therapy.Most current transducers use piezoelectric ceramics for electromechanical couplings,which will undergo periodic electro-acoustic transitions at high frequencies(≥20 MHz),thereby requiring high reliability.This work presents a structural engineering strategy to improve the piezoelectricity and reliability of potassium sodium niobate(KNN)-based ceramics with potential high-frequency ultrasonic imaging transducers.The KNN-based ceramics exhibit fatigue-free behavior with enhanced piezoelectricity(d33~550±20 pC N^(-1)),and the mechanisms are discussed in view of multi-dimensions from macroscopy to microscopy.Considering the synergistic effect of multi-phase coexistence,well-kept microstructure,and flexible domain rotation,propertyworsening cracks during fatigue are restrained;furthermore,the aggregation of space charges is hindered,thereby reducing the pinned domain and improving the fatigue resistance.Based on the high-performance piezoceramics,the fabricated ultrasonic transducer has high reliability with a steady sensitivity and an unchanged broad bandwidth(~76%)from room temperature to 80℃.In addition,images of a tilapia eyeball are scanned to confirm the imaging capability of transducers.We expect that the novel approach to achieving high performance through the structural strategy promotes KNN-based ultrasonic devices for biomedical imaging.

关 键 词：KNN 超声换能器 压电陶瓷 抗疲劳特性 频带宽度 抗疲劳性 压电性 机电耦合 

分 类 号：TM282[一般工业技术—材料科学与工程]