应用于高温条件下的新型压电复合材料超声换能器研究

This project is to research on high performance ferroelectric single crystal/polymer composite ultrasonic transducers for high temperature applications. Starting from accurate characterization and analysis of piezoelectric materials, the acoustic and electrical characteristics of ferroelectric single crystal/polymer composite ultrasonic transducers under high temperature conditions will be studied with theoretical analysis and practical testing, based upon the variation and mechanism of piezoelectric material properties with elevated temperature. Four aspects are especially to be focused on in this project. Firstly, accurate characterization method of piezoelectric materials based on double objective function optimization with fast iteration computing is to be investigated. Sencondly, effects of high temperature on piezoelectric composite ultrasonic transducers will be studied. Thirdly, research is to be carried out on effects of self-heating on piezoelectric composite ultrasonic transducers. And finally, design optimization of ferroelectric single crystal/polymer composite ultrasonic transducers for high temperature applications is to be summarized. The achievement of this project will offer the theoretical foundation and technical support to design optimization of high temperature ultrasonic transducers, improvement of their efficiency and frequency response, and their applications in the areas of industry nondestructive testing, underwater sonar, biomedical, and industry process.

本项目将开展应用于高温条件下基于新型铁电单晶/聚合物复合材料高性能超声换能器的研究。通过理论分析和实际测试，本项目将从压电材料特性精确表征和分析入手，以研究压电材料在高温条件下特性的变化及其机理为基础，进而开展采用铁电单晶/聚合物复合材料超声换能器在高温条件下的声学和电学特性研究。本项目将重点开展基于双目标函数全局优化快速迭代算法的新型压电材料参数精确表征方法研究；高温环境对压电复合材料超声换能器特性影响的研究；大功率条件下自发热对于压电复合材料超声换能器特性影响的研究；以及铁电单晶/聚合物复合材料换能器的高温特性优化设计方法研究。本项目的研究成果将为优化高性能高温超声换能器设计，提高超声换能器的工作效率和频率响应等特性，拓展在工业无损检测、水下声纳、生物医学以及工业处理等领域的应用，提供理论基础和技术支持。

本项目开展了应用于高温条件下基于新型铁电单晶/聚合物复合材料高性能超声换能器的研究。通过采用基于模拟退火优化算法的压电材料精确表征方法，计算铁电单晶及其复合材料在不同温度下的参数变化，并且将计算结果与商业软件PRAP的计算结果进行比较分析和研究，同时研究了在广泛频率内双层换能器的电气和声学特性。基于KLM等效电路理论与复合压电常数，建立了具有双反向极化的铌镁酸铅陶瓷层的换能器的理论模型。通过对材料电阻抗共振特性的拟合，获得压电单晶复合材料的常数，包括与频率有关的材料损耗特性常数等。项目还研究了温度对铁电单晶复合材料性能影响，通过制备1-3型复合材料，分析了升温过程中复合材料的参数（介电、弹性、压电、损耗特性）变化情况与温度对复合材料参数的影响机理。本项目的成果为优化高性能高温超声换能器设计，提高超声换能器的工作效率和频率响应等特性，拓展在工业无损检测、水下声纳、生物医学以及工业处理等领域的应用，提供了理论基础和技术支持。