Fabrication of textured ferroelectric ceramics by magnetic alignment via gelcasting
Fabrication of textured ferroelectric ceramics by magnetic alignment via gelcasting
复制标题
通过凝胶注模磁对准制造织构化铁电陶瓷
DOI：
10.1016/j.jeurceramsoc.2006.04.087
复制
发表时间：
2007
影响因子：
5.7
通讯作者：
K. Watari
中科院分区：
文献类型：
--
作者：
Weiwu Chen;Y. Kinemuchi;T. Tamura;K. Miwa;K. Watari
晶粒取向的铁电陶瓷由于具有接近单晶的性能而受到人们的广泛关注。本研究探索了一种结合磁性取向和凝胶注模成型的新工艺，制备了具有不同晶体结构的晶粒取向铁电陶瓷。在强磁场中，陶瓷颗粒在浆料中通过磁力排列，然后通过凝胶注模技术通过聚合锁定在原位。发现该工艺对于具有铋层状结构（Bi4Ti3O12）和钨青铜结构（Sr0.5Ba0.5Nb2O6）的铁电陶瓷是有效的。烧结样品显示出高度的各向异性结构和增强的物理性能。而对于钙钛矿结构的BaTiO_3铁电陶瓷，绿色压坯呈现晶粒取向，烧结后样品又变得无规。因此，对于使用常规陶瓷工艺的某些材料，即，使用常规的起始粉末、在强磁场（10T）下的凝胶注模和无压烧结，可以制备致密晶粒取向的陶瓷材料。
Grain-oriented ferroelectric ceramics have attracted more interest recently because they may provide near single crystal properties. In the present study, a novel process combining magnetic alignment and gelcasting was explored to prepare grain-oriented ferroelectric ceramics with different crystal structures. In a strong magnetic field, ceramic particles in slurry were aligned by the magnetic force and then locked in situ by polymerization via a gelcasting technique. This process was found effective for ferroelectric ceramics with a bismuth layer structure (Bi4Ti3O12) and tungsten bronze structure (Sr0.5Ba0.5Nb2O6). The sintered samples show highly anisotropic structure and enhanced physical properties. However for perovskite structured ferroelectric ceramics (BaTiO3), the green compact shows grain orientation, while after sintering the sample become random again. Thus for certain materials using the conventional ceramic processes, i.e., using conventional starting powders, gelcasting under strong magnetic fields (10T) and pressure-less sintering, the preparation of dense grain-oriented ceramic materials is possible.