摘要
采用烧结时在陶瓷坯体上施加一个较小的轴向压力方法实现了铋层结构Na0.5Bi4.5Ti4O15铁电陶瓷的织构化。实验表明,随压力增加,陶瓷的横向延伸率上升,材料密度略有降低。同时,XRD分析表明,轴向压力提高了平行压力方向和垂直压力方向上晶粒取向度的差异,表明施加压力有助于提高陶瓷的织构化程度。同时,电学性能测试表明,随着压力增加,压力方向上的陶瓷介电常数和损耗均随之下降。在NBT体系的烧结过程中,低熔点的Bi2O3等低熔点物质会首先熔融,形成局部液态;NBT晶粒具有片状结构,在外力和高温熔体的共同作用下,发生倾斜和滑移,产生定向排列的趋势;随后,这些局部定向的大晶粒作为模板,促进了NBT陶瓷的晶粒定向和织构化。
Grain oriented bismuth layer-structured ferroelectric (BLSF) Na0.5Bi4.5Ti4O15 ceramics were obtained by imposing small axial pressure during sintering process. Experiments reveal that the horizontal elongation of the ceramics is increased while the density is decreased by the axial pressure. Meanwhile, XRD analyses show that the axial pressure enhances the difference of the orientation degree between the direction parallel and perpendicular to pressure. Besides, electrical measurements show that with increase of the pressure, the dielectric loss and dielectric constant are both decreased in the pressure direction. These results demonstrate that axial pressure during sintering is favorable to the enhancement of grain orientation. During the sintering process, the low melting point materials including Bi2O3 would melt and form a local liquid, which is favorable to the lamellar grains in NBT ceramics tilting and sliding under the pressure, and leads to grains oriented. The local orientated grains are taken as templates, and promote grain orientation and texture of NBT ceramics.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2011年第S1期371-374,共4页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51072008)
北京市自然科学基金(2102006)
