【摘要】 针对声发射传感器在高温结构健康监测领域愈发迫切的需求,本项目旨在制备适用于高温领域的压电陶瓷及其声发射传感器。首先,通过固相反应制备了一系列的0.45(BiSc_xO₃-BiFe_1-xO₃)-0.48PbTiO₃-0.07BaTiO₃ (BSc_xFe_1-x-PT-BT,n（Sc）/n（Fe）=0.4/0.6～0.6/0.4)压电陶瓷,系统地研究了BSc_xFe_1-x-PT-BT陶瓷的微观结构和电学性能对n（Sc）/n（Fe）比例的依赖关系。所有陶瓷均呈现出典型的钙钛矿结构,且随着n（Sc）/n（Fe）的降低,晶相逐渐由菱方相向四方相转变。陶瓷的压电性能和介电性能随着n（Sc）/n（Fe）比例的降低先升高后降低。其中,BSc_0.5Fe_0.5-PT-BT和BSc_0.55Fe_0.45-PT-BT陶瓷展现了优异的压电性(d₃₃=250～281 pC/N)、高的居里温度（T_C=430～450℃）以及良好的温度稳定性。这些增强的性能是源于陶瓷准同型相界处菱方相和四方相之间的平衡以及致密的陶瓷微观结构。另外,基于BSc_0.5Fe_0.5-PTBT压电陶瓷设计、制备了声发射传感器,并对其进行了原位高温断铅测试。在200℃高温下,声发射传感器的噪声低于40 dB,声发射信号高于90 dB。因此,BSc_xFe_1-x-PT-BT压电陶瓷基声发射传感器有望被应用于高温结构健康监测中。更多还原

【Abstract】 Piezoelectric ceramic based high-temperature acoustic emission（AE） sensor is required urgently in the structural health monitoring of high-temperature fields.In this research,a series of 0.45(BiSc_xO₃-BiFe_1-xO₃)-0.48 PbTiO₃-0.07 BaTiO₃(BSc_xFe_1-x-PT-BT,n（Sc）/n（Fe）=0.4/0.6-0.6/0.4) ceramics with both high Curie temperature and large piezoelectric constant were presented.The structure and electrical properties of BSc_xFe1-_x-PT-BT ceramics as a function of n（Sc）/h（Fe） have been systematically investigated.All the ceramics possess a perovskite structure,and the phase approaches from the rhombohedral toward the tetragonal phase with the decrease of n（Sc）/n（Fe）.The BSc_0.5Fe_0.5-PT-BT and BSc_0.55Fe_0.45-PT-BT piezoelectric ceramics exhibit good piezoelectricity(d₃₃=250-281 pC/N),high Curie temperature（T_C=430-450 ℃） and excellent temperature stability.These improvements are greatly attributed to the balance between rhombohedral and tetragonal phase near morphotropic phase boundary with dense microstructure of ceramics.AE sensor based BSc_0.5Fe_0.5-PT-BT piezoelectric ceramic was designed,prepared and tested.The high-temperature stability of AE sensor was characterized through pencil-lead breaking with in situ high-temperature test.The noise of AE sensor is less than 40 dB,and the acoustic signal is up to 90 dB at 200 ℃.As a result,AE sensors based on BSc_xFe_1-x-PT-BT piezoelectric ceramics are expected to be applied into the structural health monitoring of high temperature fields.更多还原