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	纳米BaTiO_3陶瓷的Raman光谱研究
	肖长江 ; 靳常青 ; 王晓惠 ; XIAO Chang-jiang ; JIN Chang-qing ; WANG Xiao-hui
	2010-05-12 ; 2010-05-12
关键词	BaTiO3 纳米陶瓷 Raman光谱 多相共存 BaTiO3 Nanocrystalline ceramics Raman spectra Multiphase coexistence TB383.1
其他题名	Raman Studies of Nanocrystalline BaTiO_3 Ceramics
中文摘要	高压能增加陶瓷烧结的致密驱动力和抑制陶瓷晶粒的长大。用高压辅助烧结的方法得到了晶粒尺寸约为60和30 nm的致密纳米BaTiO3陶瓷。BaTiO3陶瓷的晶体结构随温度的变化由变温Raman光谱来研究。在温度范围-190℃到200℃内,与粗晶的BaTiO3陶瓷相比,纳米BaTiO3陶瓷Raman散射结果表明,随着晶粒尺寸的减小,Raman峰的强度变弱,相变越来越弥散,出现了相变峰的消失;而且随着温度的升高,在纳米BaTiO3陶瓷甚至在30 nm BaTiO3陶瓷中都有与粗晶相同的从三方相到正交相到四方相到立方相的连续相变。变温Raman散射也表明,当晶粒大小减小到纳米尺寸时,纳米BaTiO3陶瓷表现出与粗晶不同的新颖性质。在一定的温度范围内,存在多种铁电相的共存。; High pressure can significantly increase the densification.Further,during the high pressure assisted sintering,the nucleation rate is increased due to reduced energy barrier and the growth rate is suppressed due to the decreased diffusivity.Thus high pressure enables the specimen to be fabricated with relatively lower temperature and shorter sintering period that assures to obtain dense nanocrystalline ceramics.Dense nanocrystalline BaTiO3 ceramics with uniform grain sizes of 60 and 30 nm,respectively,were obtained by pressure assisted sintering.The crystal structure and phase transitions were investigated by Raman scattering at temperatures ranging from-190 to 200 ℃.The Raman results indicated that the evolution of Raman spectrum with grain size is characterized by an intensity decrease,a broadening of the line width,a frequency shift,and the disappearance of the Raman mode.With increasing temperature,similar to 3 mm BaTiO3 normal ceramics,the successive phase transitions from rhombohedral to orthorhombic,orthorhombic to tetragonal,and tetragonal to cubic were also observed in nanocrystalline BaTiO3 ceramics.In addition,when particle size is reduced to the nanoscale,one will find some unusual physical properties in nanocrystalline ceramics,compared with those of coarse-grained BaTiO3 ceramics.The different coexistences of multiphase were found at different temperature.Especially,the ferroelectric tetragonal and orthorhombic phase can coexist at room temperature in nanocrystalline BaTiO3 ceramics.The phenomenon can be explained by the internal stress.The coexistences of different ferroelectric phases at room temperature indicate that the critical grain size for the disappearance of ferroelectricity in nanocrystalline BaTiO3 ceramics fabricated by pressure assisted sintering is below 30 nm.
语种	中文 ; 中文
内容类型	期刊论文
源URL	[http://hdl.handle.net/123456789/28926]
专题	清华大学
推荐引用方式 GB/T 7714	肖长江,靳常青,王晓惠,等. 纳米BaTiO_3陶瓷的Raman光谱研究[J],2010, 2010.
APA	肖长江,靳常青,王晓惠,XIAO Chang-jiang,JIN Chang-qing,&WANG Xiao-hui.(2010).纳米BaTiO_3陶瓷的Raman光谱研究..
MLA	肖长江,et al."纳米BaTiO_3陶瓷的Raman光谱研究".(2010).

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