PMN-PT基透明陶瓷的无压烧结制备与电光性能调控研究

(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (abbr. PMN-PT) based transparent ferroelectric ceramics exhibit large electro-optic coefficient, low half-wave voltage and fast response speed. They are particularly suitable for developing electro-optic modulation devices with low drive voltage and high modulation rate, and have a bright application prospect in optical communication fields. Recently, we fabricated highly transparent PMN-PT ceramics with 67% light transmittance at 1550 nm by pressureless sintering and observed its electro-optic effect. Pressureless sintering have several advantages over hot-pressed sintering, for example, low cost and low energy consumption since sintering furnaces used are simple and cheaper, convenient for sintering transparent ceramics with complex shape, as well as suitable for large scale production. . .In this work, we will prepare PMN-PT ultrafine powders of high quality through a modified sol-gel process using cheap inorganic salts as raw materials. Then, PMN-PT transparent ceramics will be fabricated by pressureless sintering using the ultrafine powders. By adjusting the solid solution proportion and doping rare-earth elements, transparent PMN-PT ceramics with transmittance of over 70% and quadratic electro-optic coefficient of over 60×10-16 m2/V2 will be obtained. The dependences of electro-optic performance in the transparent ceramics on the solid solution proportion and rare-earth-element doping will be found. Ferroelectric domain structures in the transparent ceramics will be studied by using transmission electron microscopy and then the regulation mechanism of their electro-optic performance will be discussed. The sintering curves and microstructural evolution of PMN-PT based ceramics in pressureless sintering process will be investigated and then the sintering kinetics and densification mechanism of PMN-PT transparent ceramic will be understood.

(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (简称PMN-PT)基透明铁电陶瓷的电光系数大、半波电压低、响应速度快，非常适合开发低压驱动的高速电光调制器件，在光通信等领域应用前景诱人。最近我们无压烧成了高度透明的PMN-PT基陶瓷，其透光率达67%@1550nm，初步观测到其电光效应。与热压烧结相比，无压烧结所需设备简单廉价，无需昂贵的SiC模具，成本低，便于烧结形状复杂的透明陶瓷，更适合大规模生产。本项申请拟进一步优化无压烧结工艺，将PMN-PT基透明陶瓷的透光率提高到70%。通过调整固溶体配比和稀土元素掺杂量，将透明陶瓷的电光系数提高到30×10-16 m2/V2以上。总结固溶配比和稀土元素掺杂调控透明陶瓷电光性能的规律，用透射电镜研究透明陶瓷中的铁电畴结构，揭示其电光性能调控机理。研究透明陶瓷的无压烧结曲线和显微结构演变，探讨其无压烧结致密化机理。

(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (简称PMN-PT)基透明陶瓷的电光系数大、半波电压低、响应速度快，非常适合开发低压驱动的高速电光调制器件，在光通信等领域应用前景诱人，但是制备工艺不成熟大大限制了PMN-PT基透明陶瓷的应用。目前世界上只有美国波士顿科技公司成功制备了可实用化的PMN-PT基透明陶瓷，并研发出一系列高性能电光器件。我们从事PMN-PT基材料制备与性能研究10余年，近几年用气氛烧结和热压烧结相结合的烧结工艺成功制备了透光率达70%的PMN-PT基陶瓷，已接近其理论透光率~71%，基本达到了实用要求，并且具有优异的电光性能，二次电光系数>50×10-16 m2/V2，低的半波电压~200V/mm。研究了稀土元素掺杂，制备工艺等因素对该材料的结构和性能的影响，并在此基础上开发出基于PMN-PT透明陶瓷的电光开关与调制器原型器件，为其实际应用打下一定基础。