高压烧结纳米钛酸钡陶瓷的结构和铁电性  

CRYSTAL STRUCTURE AND FERROELECTRICITY OF NANOCRYSTALLINE BARIUM TITANATE CERAMICS FABRICATED BY THE HIGH PRESSURE SINTERING

作　　者：肖长江[1] 靳常青[2] 王晓慧[3] 

机构地区：[1]河南工业大学材料科学与工程学院,郑州450007 [2]中国科学院物理研究所,北京100080 [3]清华大学材料科学与工程系新型陶瓷和精细工艺国家重点实验室,北京100084

出　　处：《硅酸盐学报》2008年第6期748-750,共3页Journal of The Chinese Ceramic Society

基　　金：国家“973”计划(2002CB613301)资助项目

摘　　要：在压力为6GPa和温度为1000℃的条件下烧结得到了钛酸钡(BaTiO3)陶瓷,其晶体的平均尺寸约为30nm,相对密度大于96%。在–190～200℃,用Raman光谱确定晶体的结构,用介电转变峰表征晶体的铁电性。结果表明:随温度升高,在30nm BaTiO3陶瓷中,发生从三方相→正交相→四方相→三方相的连续相变;在室温,晶体的正交相和四方相共存。当频率为1kHz时,在120℃附近有1个宽的介电转变峰,介电常数为1920。铁电性分析表明:高压烧结得到的BaTiO3陶瓷的铁电性消失的临界尺寸小于30nm。Barium titanate （BaTiO3） ceramics were sintered at 6 GPa and 1 000 ℃. The average grain size of the crystalline was about 30 nm and the relative density was more than 96%. The crystal structure was investigated by Raman scattering at temperatures ranging from -190 ℃ to 200 ℃ and the ferroelectricity was characterized by the dielectric transition peak. With increasing temperature, the successive phase transitions from rhombohedral to orthorhombic, orthorhombic to tetragonal and tetragonal to cubic were also observed in 30 nm BaTiO3 ceramics. The coexistence of ferroelectric tetragonal and orthorbombic phases was found at room temperature. At about 120 ℃, there existed a broad dielectric peak and the relative dielectric constant was 1 920. The existence of ferroelectricity indicated that the critical grain size of the disappearance of ferroelectricity in nano-crystalline BaTiO3 ceramics fabricated by the pressure sintering is below 30 nm.

关 键 词：钛酸钡 纳米陶瓷 高压烧结 晶体结构 铁电性 

分 类 号：TB34[一般工业技术—材料科学与工程]