-用固相反应法制备了B位空位补偿型钐掺杂非准同型相界组分PZT(54/46)陶瓷.通过正电子湮没寿命谱(PALS)和符合多普勒展宽能谱(CDBS)对陶瓷中的缺陷结构进行综合表征,结合常规表征手段如X射线衍射(XRD),电子扫描显微镜(SEM),介电、铁电...-用固相反应法制备了B位空位补偿型钐掺杂非准同型相界组分PZT(54/46)陶瓷.通过正电子湮没寿命谱(PALS)和符合多普勒展宽能谱(CDBS)对陶瓷中的缺陷结构进行综合表征,结合常规表征手段如X射线衍射(XRD),电子扫描显微镜(SEM),介电、铁电和压电性能测量,研究缺陷对陶瓷压电性能的影响.XRD结果显示所有陶瓷均为纯钙钛矿相,掺杂诱导了菱方-四方(R-T)相变,准同型相界位于Sm掺杂量x=0.010.02.电学测量结果反映:介电、铁电和压电性能均先增强后减弱,MPB附近两个样品都有优异的介电和铁电性能,但其压电性能差别很大.x=0.01给出最优压电性能d_(33)=572 p C/N,较未掺杂样品增强了一倍.PALS结果表明掺杂使陶瓷中缺陷类型发生变化,x≤0.01,样品中同时含有A位空位与B位空位;x≥0.02,样品中以A位相关缺陷为主,B位空位浓度很低.CDBS结果进一步证实x=0.01和0.02中B位空位浓度分别是该体系中最高和最低的.由以上结果推断出:x=0.01获得的最优压电性能与其中较高浓度的B位空位有关,B位空位可稀释A位空位浓度,降低氧空位浓度,从而降低A位空位与氧空位形成缺陷偶极子的几率,促进畴壁运动,使压电性能增强.展开更多
The synergistic effect of triple ion beams is investigated by simultaneous and scquential irradiations of gold, hydrogen and helium ions on the low activation martensitie steel （CLAM） developed in China. The depth p...The synergistic effect of triple ion beams is investigated by simultaneous and scquential irradiations of gold, hydrogen and helium ions on the low activation martensitie steel （CLAM） developed in China. The depth profile measurements of the positron annihilation Doppler broadening S parameter are carried out as a function of slow- positron beam energy to examine the produced radiation damage. The synergistic effect of displacement damage and hydrogen and helium on the formation of radiation damage is clearly observed. In the preset case ,this effect suppresses the radiation damage in the CLAM steel due to the helium and/or hydrogen filling of vacancy clusters.展开更多
Evolutions of defects and helium contained defects produced by atomic displacement and helium deposition with helium implantation at different temperatures in novel high silicon （NHS） steel are investigated by a slo...Evolutions of defects and helium contained defects produced by atomic displacement and helium deposition with helium implantation at different temperatures in novel high silicon （NHS） steel are investigated by a slow positron beam. Differences of the defect information among samples implanted by helium to a fluence of 1×1017 ions/cm2 at room temperature, 300°C, 450°C and 750°C are discussed. It is found that the mobility of vacancies and vacancy clusters, a recombination of vacancy-type defects and the formation of the He-V complex lead to the occurrence of these differences. At high temperature irradiations, a change of the diffusion mechanism of He atoms/He bubbles might be one of the reasons for the change of the S-parameter.展开更多
文摘-用固相反应法制备了B位空位补偿型钐掺杂非准同型相界组分PZT(54/46)陶瓷.通过正电子湮没寿命谱(PALS)和符合多普勒展宽能谱(CDBS)对陶瓷中的缺陷结构进行综合表征,结合常规表征手段如X射线衍射(XRD),电子扫描显微镜(SEM),介电、铁电和压电性能测量,研究缺陷对陶瓷压电性能的影响.XRD结果显示所有陶瓷均为纯钙钛矿相,掺杂诱导了菱方-四方(R-T)相变,准同型相界位于Sm掺杂量x=0.010.02.电学测量结果反映:介电、铁电和压电性能均先增强后减弱,MPB附近两个样品都有优异的介电和铁电性能,但其压电性能差别很大.x=0.01给出最优压电性能d_(33)=572 p C/N,较未掺杂样品增强了一倍.PALS结果表明掺杂使陶瓷中缺陷类型发生变化,x≤0.01,样品中同时含有A位空位与B位空位;x≥0.02,样品中以A位相关缺陷为主,B位空位浓度很低.CDBS结果进一步证实x=0.01和0.02中B位空位浓度分别是该体系中最高和最低的.由以上结果推断出:x=0.01获得的最优压电性能与其中较高浓度的B位空位有关,B位空位可稀释A位空位浓度,降低氧空位浓度,从而降低A位空位与氧空位形成缺陷偶极子的几率,促进畴壁运动,使压电性能增强.
基金Supported by the National Natural Science Foundation of China under Grant Nos 91126002 and 11005158, the National Major Project of Science and Technology under Grant No 2012ZX06004-005-005, the State Major Basic Research Development Program of China under Grant No 2007CB209900, and the Fund of International Atomic Energy Agency under Grant No 15165/R0.
文摘The synergistic effect of triple ion beams is investigated by simultaneous and scquential irradiations of gold, hydrogen and helium ions on the low activation martensitie steel （CLAM） developed in China. The depth profile measurements of the positron annihilation Doppler broadening S parameter are carried out as a function of slow- positron beam energy to examine the produced radiation damage. The synergistic effect of displacement damage and hydrogen and helium on the formation of radiation damage is clearly observed. In the preset case ,this effect suppresses the radiation damage in the CLAM steel due to the helium and/or hydrogen filling of vacancy clusters.
基金Supported by the National Basic Research Program of China under Grant No 2010CB832902, and the National Natural Science Foundation of China under Grant Nos 91026002, 91126011 and 11275005.
文摘Evolutions of defects and helium contained defects produced by atomic displacement and helium deposition with helium implantation at different temperatures in novel high silicon （NHS） steel are investigated by a slow positron beam. Differences of the defect information among samples implanted by helium to a fluence of 1×1017 ions/cm2 at room temperature, 300°C, 450°C and 750°C are discussed. It is found that the mobility of vacancies and vacancy clusters, a recombination of vacancy-type defects and the formation of the He-V complex lead to the occurrence of these differences. At high temperature irradiations, a change of the diffusion mechanism of He atoms/He bubbles might be one of the reasons for the change of the S-parameter.
