High-temperature creep resistance in lanthanoid ion-doped polycrystalline Al2O3
High-temperature creep resistance in lanthanoid ion-doped polycrystalline Al2O3
复制标题
镧系离子掺杂多晶 Al2O3 的高温抗蠕变性能
DOI：
10.1080/095008399177318
复制
发表时间：
1999
影响因子：
1.2
通讯作者：
T. Sakuma
中科院分区：
文献类型：
--
作者：
H. Yoshida;Y. Ikuhara;T. Sakuma
用1250oC单轴压缩蠕变试验研究了添加0.05mol%Y、Sm、Eu、Tm、Lu等稀土氧化物的多晶Al_2O_3的高温蠕变性能。掺杂改善了材料的抗蠕变性能，掺杂效应与稀土元素的种类有关，其影响顺序为Sm<；Tm<；Eu<；Y<；Lu。发现每一种掺杂阳离子都偏聚在晶界上，并可能抑制晶界扩散。采用离散变分(DV)X方法，通过第一性原理分子轨道计算，估算了化学键状态随掺杂的变化。蠕变抗力与组成离子的α净电荷之间有很好的相关性。La3+偏析引起晶界离子键态的变化一定是多晶Al_2O_3蠕变抗力提高的原因。
High-temperature creep resistance in polycrystalline Al2O3 with 0.05 mol% lanthanoid oxides of Y, Sm, Eu, Tm or Lu has been examined by uniaxial compression creep testing at 1250oC. The creep resistance is improved by the doping, and the dopant effect is dependent on the type of lanthanoid; the effect is in the order Sm < Tm < Eu < Y < Lu. Each dopant cation was found to segregate in grain boundaries and is likely to suppress grain-boundary diffusion. The change in chemical bonding state with doping was estimated by a first-principles molecular orbital calculation using the discrete variational (DV)X method. A good correlation is found between the creep resistance and the net alpha charge of the constituent ions. A change in the ionic bonding state in grain boundaries due to lanthanoid segregation must be the origin of the improved creep resistance in polycrystalline Al2O3.