深海热液喷口探测用低温烧结超高温压电陶瓷新体系设计及机理研究

The temperatures of seafloor hydrothermal vents may be as high as 350~450℃. It requires that the detection equipment and key material must both meet the low-frequency high-power and high temperature characteristic. The array or multi-layer structure ceramic transducers are the effective ways to improve the power output of acoustic detection equipment. Low temperature co-firing ceramic technology provide a new way to solve the limitations of the traditional Array and Multi-layer transducer process, and improve the flexibility of the transducer design. The project intends to design new glass-free low-temperature sintering high Curie temperature high depolarization temperature piezoelectric ceramics based on the basic principle of the piezoelectric effect and solid-state sintering, and combined with first-principles calculation. Meanwhile, by analyzing the XRD and vibration spectrum, investigated the relationship between micro-structural factors (such as bond structure, packing fraction and molecular vibration) and the Curie temperature, depolarization temperature, dielectric/piezoelectric properties, and understood the mechanisms about performance modification of doping or composite systems. Moreover, in order to accommodate the low temperature firing properties and performance modification, the low temperature firing characteristics and performance modification regulation laws were investigated by sintering kinetics researching such as calculation of oxygen ion diffusion coefficient and solid-state sintering diffusion activation energy. And also, the matching on electrode and co-fire material, and the digital control of synthesis and molding were investigated. It can provide the theoretical basis and technical support for low temperature co-firing array and multilayer piezoelectric ceramic structure researching with the application of seafloor hydrothermal vents detection. It is of great importance from both theoretical and application points of view.

深海热液垂直喷口温度高达350~450℃，要求探测设备及关键材料同时满足低频大功率及耐高温特性。阵列及多层结构陶瓷换能器是提高声学探测设备输出功率的有效途径。低温共烧陶瓷相关工艺理念可突破阵列及多层结构陶瓷换能器传统工艺局限，为提高换能器设计的灵活性提供新思路。本项目拟从压电效应基本原理及固相烧结相关原理出发，结合第一性原理计算，设计无玻璃相低温烧结超高温压电陶瓷新材料。通过XRD、振动光谱分析研究化学键结构、原子堆积密度及分子振动等微结构因素与居里温度、退极化温度及介电压电性能的关系，探索新体系及掺杂复合体系性能调控规律；通过氧离子扩散系数及固相烧结扩散活化能等烧结动力学研究揭示体系低烧特性及性能调控规律；并全面研究电极与材料共烧匹配性、合成及成型工艺的数字化控制，为深海热液喷口探测用低温共烧阵列及多层结构压电陶瓷的研究提供理论依据及技术支撑。本项目研究兼具重要理论意义与实用价值。

深海热液垂直喷口温度高达350~400℃，要求探测及关键材料同时满足低频大功率及耐高温特性。阵列及多层结构陶瓷换能器是提高声学探测设备输出功率的有效途径。低温共烧陶瓷相关工艺理念可突破阵列及多层结构陶瓷换能器传统工艺局限，为提高换能器设计的灵活性提供新思路。本项目从压电效应基本原理及固要上烧结相关原理出发，结合第一性原理计算，设计制备了系列化无玻璃相低温烧结超高温压电陶瓷新材料Bi2（1-x）BxWO6 (B=La, Mn, Cr等)。其中：Bi1.98La0.02WO6材料综合性能如下：Tc =905℃，Td =880℃，Qm=1642.3，d33=17pC/N，ε=82.01，tanδ=0.19×10-2；Bi1.94Mn0.06WO6材料综合性能如下：Tc =890℃，Td =825℃，Qm=439.2，d33=15pC/N，ε=92，tanδ=0.17×10-2；Bi1.92Cr0.08WO6材料综合性能如下：Tc =750℃，Td =480℃，Qm=808，d33=30pC/N，ε=420，tanδ=0.20×10-2。选择代表性压电陶瓷体系，通过XRD等微观分析手段探索了退极化机理。为研究低温共烧多层陶瓷，研制了配套低温导电银胶。其中：Ag-80环氧树脂/乙二胺固化纳米导电银胶综合性能：固化温度：100℃，固化时间：30分钟，体积电阻率：1.973×10-4Ω·cm，焊点粘接强度：7.93MPa；铝粉氧化锌粉末掺杂纳米导电银胶综合性能：固化温度：100℃，固化时间：30分钟，体积电阻率：1.119×10-4Ω·cm，焊点剪切强度：34.84MPa，焊点粘接强度：17.00MPa；E51环氧树脂/双氰胺导电银胶综合性能：固化温度：100℃，固化时间：30分钟，体积电阻率：0.421×10-4Ω·cm，剪切强度：14.03MPa；锌白铜掺杂纳米导电银胶综合性能：固化温度：100℃，固化时间：30分钟，体积电阻率：1.68×10–4Ω•cm，温度系数：0.0057/℃。本项目的研究成果可应用于深海探测定位系统、水下通信、移动通信、无线互联网、无线传感网络以及医学诊断等各领域，具有强大的工业生产潜力，可带来良好的经济效益。项目完成将为信息、医疗、材料产业发展提供技术基础，为科技、经济和社会发展做贡献。