摘要
采用坩埚下降法成功生长出尺寸达φ15mm×50mm的0.94Na1/2Bi1/2TiO3-06BaTiO3(NBBT94/6)无铅压电单晶。利用X射线荧光沿纵向对晶体棒成分分析表明:Na+、Bi3+、Ti3+离子的含量沿纵向波动较小,而Ba2+离子的含量却波动较大。XRD结构分析表明,晶体棒的中、下部分属于三方相钙钛矿结构,而上部转变为四方相钙钛矿结构。详细研究晶体棒中部0.952Na1/2Bi1/2TiO3-0.048BaTiO3(NBBT95.2/4.8)的介电及压电行为表明:非自发极化方向[001]、[110]样品的退极化温度乃分别为200℃和150℃,具有明显的结晶学方向依赖性,且在Td附近表现出典型的介电弛豫行为;在3~5kV/mm电压极化下,[001]、[110]方向样品的最大压电系数d33分别为165pC/N、110pC/N,机电耦合系数k1分别为49.8%、45.0%。
Lead-free piezoelectric crystal of 0. 94Na1/2 Bi1/2 TiO3-0. 06BaTiO3 ( NBBT94/6 ) with a dimension of φ15 mm ×50 mm has been successfully grown by Bridgman technique. X-ray fluorescence analysis reveals that the concentrations of Na+ , Bi3+ and Ti4+ vary slightly along the growth direction, while the concentration of Ba2+ varies greatly. XRD shows that the grown crystals are of pure perovskite structure with a rhombohedral symmetry in the bottom and middle parts, while the upper part belongs to tetragonal symmetry. The dielectric and piezoelectric properties for 0. 952Na1/2Bi1/2TiO3-0. 048BaTiO3 (NBBT95.2/4.8) crystals were mainly investigated in detail. The results show that the [001 ], [ 110] samples possess relaxor dielectric behavior and Td of [001 ],[110] samples are 200℃, 150℃ respectively, obviously depending on crystallographic direction. Moreover, maximum d33 of 165 pC/N,110 pC/N and kt of 49.8% , 45.0% are obtained for the [001 ] , [ 110] samples poled under 3-5 kV/ mm, respectively.
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2008年第4期881-885,共5页
Journal of Synthetic Crystals
基金
国家自然科学基金(No.50562002,50602047)
教育部新世纪优秀人才计划(NCET-06-0576)
江西省自然科学基金(0650074,2007GZC1258)
上海硅酸盐研究所高性能陶瓷国家重点实验室开放课题(SKL200610SIC)
关键词
钛酸铋钠
无铅
晶体生长
介电弛豫
压电性能
sodium bismuth titanate
lead-free
crystal growth
dielectric relaxor
piezoelectric properties