固结压强对纳米PbF_2的相变和离子电导率的影响  

INFLUENCE OF CONSOLIDATED PRESSURE UPON PHASE TRANSITION AND IONIC CONDUCTIVITY OF NANOPHASE PbF_2

作　　者：刘金芳[1] 吴希俊[1] 许国良[1] 周宇松[1] 李冰寒 

机构地区：[1]浙江大学材料科学与工程系,杭州310027

出　　处：《高压物理学报》2000年第1期16-21,共6页Chinese Journal of High Pressure Physics

基　　金：国家自然科学基金资助!( 5 9872 0 31);教育部博士学科点基金资助! ( 94335 10 );浙江大学华为教育科研发展基金资助

摘　　要：用惰性气体蒸发 真空原位固结法制备了直径为 10mm、厚度为 1～ 2mm的具有清洁界面的纳米PbF2 块体材料 ,原位固结压强为 0 .3～ 1.8GPa。采用X射线衍射和复阻抗谱方法 ,研究了固结压强对纳米PbF2 物相组成、晶粒度和离子电导率的影响。结果表明 ,相同压强下 ,纳米 β PbF2比粗晶 β PbF2 更易于向α PbF2 转化 ;随着压强增大 ,样品中低电导率的α PbF2 相不断增加 ,导致离子电导率下降。压强引起的连续相变使晶粒度缓慢长大。由于晶粒细小 ,纳米α PbF2 的离子电导率比粗晶α PbF2 提高约一个数量级 ,与粗晶 β PbF2 相当。The bulk samples with a diameter of 10mm and thickness of 1 to 2mm of nanophase PbF 2 were prepared by using an inert gas evaporation and in situ consolidating method under the pressure range from 0 3GPa to 1.8GPa.The average grain size and phase identification were studied by X ray diffraction.The ionic conductivity was measured precisely by means of the complex impedance spectra.The results show that the phase content of α PbF 2 enhances from 21.6% to 94.5% when the consolidated pressure increases from 0.3GPa to 1.8GPa.The ionic conductivity of nanophase PbF 2 is about one order of magnitude higher than that of coarse grain α PbF 2,and is approximately equal to that of coarse grain β PbF 2.

关 键 词：纳米氟化物 固结压强 结构相变 离子电导率 

分 类 号：TB383[一般工业技术—材料科学与工程]