在氧化颗粒边界中,电子和几何对结合的贡献者
Rajat Goel1, Nir Goldman1,2, Ambarish R Kulkarni1
1Department of Chemical Engineering, University of California, Davis, Davis, California 95616, United States.
概括
的腐蚀带来了安全风险. 这项研究揭示了二氧化在粒边界的吸收能力更强,在不同边界类型的反应性不同,为核材料存储提供了洞察力.
科学领域:
- 材料科学 材料科学 材料科学
- 核工程 核工程是指核工程.
- 物理化学 物理化学
背景情况:
- 由引起的腐蚀形成有毒的UH3,这是核材料储存的主要安全问题.
- 现有研究表明,通过氧化物层谷物边界 (GBs) 扩散,以启动腐蚀.
- 控制这种启动的精确原子化机制和结构因素仍然不太清楚.
研究的目的:
- 研究缺陷的二氧化 (UO2) 中吸附的原子化机制.
- 探索不同谷物边界 (GB) 结构在相互作用中的作用.
- 为开发核材料腐蚀减缓策略提供基本见解.
主要方法:
- 采用高通量密度函数理论 (DFT) 工作流.
- 研究了原子 (H) 和分子 (H2) 在分别107个和26个位点的吸附.
- 分析了在三个不同的一致点网格 (CSL) 粒度边界中的吸附: Σ3, Σ5 和 Σ9.
主要成果:
- 与原始的UO2相比,在GB地点观察到显著更强的吸附.
- 在研究的GB模型 (Σ3, Σ5, Σ9) 中,和H2吸附趋势在很大程度上存在差异.
- 在 Σ5 和 Σ9 GB 的特定位置发现了 H 的外热吸附,但在 Σ3 GB 中没有发现.
结论:
- 在UO2中,颗粒边界表现出增强的吸附能力.
- 谷物边界的特定结构极大地影响相互作用和潜在的腐蚀启动.
- 这些发现提供了关键的原子学数据,可以为减轻核材料储存中的腐蚀的策略提供信息.
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