Dy在钛酸钡中与位占据相关的缺陷化学研究

发布时间：2018-02-03 03:22

  本文关键词： 镝掺杂钛酸钡 X射线衍射 介电性能 EPR SEM　出处：《东北师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：本实验主要通过在钛酸钡中添加稀土元素Dy进行单掺或双掺来改变陶瓷性能,研充相关缺陷化学。运用XRD、SEM、EDS、EPR、RS以及介电测试系统等微观分析手段,讨论了(Ba1-xDyx)(Ti1-xDyx)O3单掺和(Ba1-xLax)(Ti1-xDyx)O3、(Ba1-xDyx)(Ti1-x/2Cax/2)O3、 (Ba1-xRx)(Ti1-xDyx)03 (R= Eu、Gd、Tb)双掺系列陶瓷改性行为和微观补偿机理,并最终制得了符合高介电Y5V和介电温度稳定型的X8R规格介质材料。同时,还对不同烧结温度下(Ba1-xDyx)Ti1-x/4O3 (x=0.01)陶瓷的固溶度、位占据、相结构和表面形貌进行了研究。Dy在自补偿模式(Ba1-xDyx)(Ti1-xDyx) O3中的固溶度是x=0.07。随着x含量的增加,自补偿模式的介电行为从一级相变转变为扩散相变再转变为具有高介电常数的Y7R介电温度稳定型。一个非常强的g=1.974 EPR信号出现在有意设计的Ti-空位单相(Ba1-xDyx)Ti1-x/4O3陶瓷中。该信号被视为Ba-空位缺陷信号。(Ba1-xDyx)Ti1-x/4O3陶瓷的真实分子式可以表示为(Ba1-xDy3x/4)(Ti1-x/4Dyx/4)O3。在(Ba1-xLax)(Ti1-xDyx)O3 (0.03≤x≤0.20)陶瓷中,La3+-Dy3+缺陷复合体的固溶度为x=0.17。随着掺杂量x的增加,晶胞体积呈线性增大趋势并满足Vegard's定律。Tm随LaBa·-DYTi'含量的增加以-23℃/at.%的速度向低温方向移动。x=0.05和0.07的BLTD陶瓷满足介电Y5V规格。一个弱的g=2.004EPR信号出现在所有的BLTD陶瓷中,该信号被视为Ti空位缺陷信号。La3+离子在Ba位的排他性占据和Dy3+离子的自补偿模式倾向要为LaBa·-DYTi'缺陷复合体的形成,少量Ti空位的出现和DyB。-DyTi缺陷复合体的形成负责。(Ba1-xDyx)(Ti1-x/2Cax/2)O3 (0.04≤x≤0.30) (BDTC)陶瓷的固溶度是x=0.15。BDTC的单胞体积随着x的增加总体呈现增大趋势。x≤0.08时,Tm随掺杂含量的增加逐渐向低温移动。BDTC陶瓷在x=0.10和0.15时满足介电温度稳定型X8R规格。所有BDTC试样中均出现g=2.004的Ti空位缺陷信号。掺杂量x=0.06时,(Ba1-xRx)(Ti1-xDyx)O3(其中：R=Eu、Gd、Tb)系列陶瓷完全并入BaTiO3晶格形成相应固溶体。在Eu/Dy共掺杂的BaTiO3中Eu离子以混和价态Eu3+/Eu2+存在于BaTiO3的Ba位；部分Dy3+不可避免地进入Ba位。在Gd/Dy共掺杂的BaTiO3中观察到了Gd3+所特有的g=1.984信号。TD6陶瓷中部分Tb以Tb4+形式进入Ti位,并伴随着少量的Dy3+进入Ba位。随着烧结温度的增加,掺杂剂在(Ba1-xDyx)Ti1-x/4O3 (x=0.01)陶瓷中扩散程度增大；有利于Dy从钛酸钡陶瓷的Ba-位扩散进入Ti-位最终引起单胞体积变大。烧结温度没有对BD1AT的相结构造成影响。
[Abstract]:In this experiment, the properties of ceramics were changed by adding rare earth element Dy to barium titanate, and the related defect chemistry was studied. The microcosmic analysis methods such as RS and dielectric measurement system are used to discuss the monoincorporation of Ti1-xDyxO3 and Ti1-xDy xO3Ti1-xDy xO3.The results are as follows: (1) Ba _ (1) -x Dy _ (x) O _ (3). Ba1-xDyx / Ti1-x / 2Cax-2O3, Ba1-xRxTy / Ti1-xDyxc03 = EuGd. The modified behavior and microcosmic compensation mechanism of Tb- doped series ceramics were obtained. Finally, the X8R dielectric materials which accord with the high dielectric Y5V and dielectric temperature stability type were prepared. At the same time. The solid solubility and potential occupation of Ba1-xDyxTi1-xTi1-x / 4O3OXX 0.01) ceramics at different sintering temperatures were also investigated. The phase structure and surface morphology were studied. The solution degree of Dy in the self-compensated mode Ba1-xDyxTi1-xDyxO3 is x0. 07. With the increase of x content. The dielectric behavior of self-compensation mode is changed from first-order phase transition to diffusion phase transition to Y7R dielectric temperature stable type with high dielectric constant. A very strong gn 1.974. The EPR signal appears in the intentionally designed Ti-vacancy single phase (. In Ba1-xDyx)Ti1-x/4O3 ceramics. This signal is regarded as Ba-vacancy defect signal. Ba-Ba1-xDyx). The true molecular formula of Ti1-x/4O3 ceramics can be expressed as Ba1-xDy3x / 4x / 4Dyx / 4Dyx / 4Dy / O3. In Ti1-xDyx)O3 0.03 鈮，

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