Effect of Nonstoichiometry on Neutron-Irradiation-Behavior of Spinel

非化学计量对尖晶石中子辐照行为的影响

基本信息

批准号：
10480105
负责人：
YANO Toyohiko
金额：
$ 7.36万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

In this study, the effects of nonstoichiometry on neutron-induced damages of spinel were investigated by measuring length change, lattice parameter change, change in thermal diffusivity, changes in mechanical properties after neutron irradiation of synthetic spinel with different stoichiometry. The recovery of these properties was also evaluated. Furthermore, neutron-induced damages of other ceramics were observed for comparison. The main results obtained were summarized as follows. (1) Macroscopic length change and lattice parameter changes of spinel irradiated at lower temperatures corresponded well each other and increased with increasing n. The change in Vickers hardness was the same tendency. After annealing, the macroscopic length and lattice parameter shrunk gradually from the irradiation temperature to 550℃, then made small peak at 650℃, finally it was not changed above 800℃. From this results, it is suggested that the recombination of Frenkel pairs up to 800℃ and rearrangement in cations at around 650℃ are happened. (2) Knoop microhardness anisotropy of n=3 spinel was measured before and after irradiation, and after post-irradiation annealing. It was changed by neutron irradiation, but recovered to that of before irradiation after annealing. The anisotropy profile of n=3 spinel was different from that of stoichiometric spinel, due to the different degree of cation distribution. Change in Vicker's hardness by neutron irradiation was proportional to the square of volume change. (3) Cation distribution of spinel in tetrahedral sites and octahedral sites could not be detected by X-ray microprobe analysis coupled with profile analysis and temperature calibration on a present EPMA apparatus. By use of ALCHEMI analysis, it could be detected, and it was found that cation distribution in spinel changed toward more random distribution by neutron irradiation. (4) Physical property change in Al_2O_3, AlN, SiC and Si_3N_4 after heavy neutron irradiation was evaluated.

在该研究中，通过测量长度变化，热扩散率的变化，中子的变化，与这些特性相关的合成尖晶石后，对中子诱导的尖晶石的损害的影响进行了研究。 h的n在退火后，Vickers的变化是相同的趋势。在辐射之前和之后，测量了n = 3的尖旋的阳离子，阳离子的阳离子在阳离子周围和阳离子各向异性时，阳离子各向异性的重排和重新排列。由于辐射的程度不同，因此从X射线微探针分析中，通过使用藻类分析的X射线微探针分析，通过辐射的平方而言，这是由于辐射的平方。可以发现，在评估了沉重的中子辐照后，尖晶石中的阳离子分布改变了中子属性的更随机分布。