新型相变储能铁电陶瓷PZ-BMN相结构与性能研究

Ferroelectric pulsed power plays an important role in the military and high-tech fields. PbZrO3(PZ)-based ferroelectric ceramics with composition near the phase boundary of ferroelectric (FE) and antiferroelectric (AFE) phase are now the key materials for ferroelectric pulsed power applications. However, a bottleneck problem that the degradation of polarization arises from the phase transition from low-temperature-rhombohedral-ferroelectric (FRLT) phase to high-temperature-rhombohedral-ferroelectric (FRHT) phase, inhibits the application of ferroelectric pulsed powers, by decreasing the temperature stability of the energy output signals. .In this proposal, Ba(Mg1/3Nb2/3)O3 (BMN) will be incorporated into the PZ ceramics to tailor the FE/AFE and FRLT/FRHT phase boundaries, aiming at obtaining a novel PZ-BMN phase transition ferroelectric ceramic with excellent ferroelectric properties and temperature stability of energy storage. Neutron diffraction and electrical measurements will be employed to characterize the phase structure and dielectric, pyoelectric and ferroelectric properties, to map out the composition-temperature phase diagram of PZ-BMN systems near FE/AFE boundary, and to interpret the microscopic mechanism of composition on tailoring the phase structure and the temperature stability of energe storage. The mechanical-electrical energy conversion behavior under hydrostatic pressure and shock compression will be investigated for the purpose of application. Relationship and physical mechanism between the macroscopic response under the pressure and phase structure will also be proposed. .The forthcoming results of this proposal will benefit to understand the physics and phase transition behaviors of PZ-BMN ferroelectric ceramics and to develop a new ferroelectric candidate for the pulsed power supply applications.

铁电体高功率脉冲电源在国防和高新技术领域具有重要应用。组分处于铁电/反铁电相界附近的锆酸铅（PZ）基铁电陶瓷是铁电体脉冲电源的核心储能材料。但PZ基铁电陶瓷仍面临高/低温铁电相变引起剩余极化强度降低的技术瓶颈，影响铁电体脉冲电源能量输出的温度稳定性。本项目拟引入铌镁酸钡（BMN）调控PZ基铁电陶瓷的相界，设计出储能特性优异的PZ-BMN铁电陶瓷。利用中子衍射研究PZ-BMN铁电陶瓷相结构及相结构演化，利用电学测试技术研究PZ-BMN铁电陶瓷介电、铁电、热释电性能，构建PZ-BMN陶瓷组成-温度相图，揭示组成调控其相结构及储能特性温度稳定性的微观机理。研究等静压和冲击波加载下PZ-BMN铁电陶瓷的能量转化行为，揭示应力加载条件下PZ-BMN铁电陶瓷力-电换能机制。本项目的实施有助于加深PZ-BMN铁电陶瓷的相变行为及能量转换机制的认识，发展出一种新型的相变储能铁电陶瓷体系。

本项目按照任务书规定的研究任务和目标，针对铁电体脉冲电源用PZ基铁电陶瓷在工程应用中存在的储能特性温度稳定性问题，通过BMN调控PZ基铁电陶瓷相界，制备出了综合性能优异的PZ-BMN相变铁电陶瓷；研究了组分以及外场对于PZ-BMN相变铁电陶瓷结构及性能的影响规律，构建了PZ-BMN铁电陶瓷组成-温度相图，揭示储能特性温度稳定性的增强机制；提升了铁电体脉冲电源在服役环境下储能特性温度稳定性问题。较好地完成了任务书的研究内容和研究目标， 对研发铁电体脉冲功率技术用新一代铁电陶瓷材料，具有重要的科学意义和实用价值。主要研究内容和研究结果如下：.（1）通过前驱体法和固相烧结法制备出四种组分PZ-BMN陶瓷，获得了优异的铁电性能。不同的烧结温度带来不同的晶粒尺寸，随着晶粒尺寸的增大，铁电性能增强。TEM研究发现这主要是由于大晶粒尺寸90°畴宽度变窄，畴壁运动增强，极化强度增强。.（2）通过中子衍射、TEM以及电学性能测试对其畴结构和相结构进行了深入系统的研究，发现随着BMN组分的增加，（1-x）PZ-xBMN陶瓷由反铁电相变为铁电相，再转变为驰豫铁电相。极化后衍射的位置没有发生明显变化，衍射峰的相对强度发生变化，说明铁电畴的翻转影响了衍射峰的强度。根据结构表征和电性能测试结果，构建了（1-x）PZ-xBMN陶瓷温度-组成相图。变温研究发现，PZ-xBMN铁电陶瓷不具有高低温铁电相变，从而具有优异的储能特性温度稳定性。.（3）等静压下退极化测试结果表明，在较低的压力下发生铁电-反铁电相变退极化；并且压力下的退极化是一种不可逆过程。等静压力和强电场下出现的双电滞回线测试结果表明，此退极化过程与PZT95/5铁电陶瓷类似，发生了铁电-反铁电（FE-AFE）相变。PZ-BMN不存在高低温相变温度，具有较好的储能温度稳定性。.（4）发表相关学术论文2篇，授权专利1项，培养参研青年1名，研究生4名。