Li Longxian, Zhu Min, Zheng Guikai, Li Yan, Yang Yang, Liu Yilong, Su Huan
College of Nuclear Science and Technology, Naval University of Engineering, Wuhan 430000, China.
Unit 93671 of the Chinese People's Liberation Army, Nanyang 473000, China.
Materials (Basel). 2022 Jul 20;15(14):5035. doi: 10.3390/ma15145035.
To deeply understand the adsorption process of oxygen on the surface of a plutonium gallium system and to reveal the chemical reaction mechanism at the initial stage of oxidative corrosion on the surface of plutonium gallium alloy at a theoretical level, the adsorption behavior of oxygen molecules on the surface of a plutonium gallium system was investigated by a first-principles approach based on density flooding theory. The results show that the molecular bond length increases and finally breaks when the surface oxygen molecule is adsorbed on the surface of plutonium gallium system and dissociates into two atomic states. The most likely adsorption position of oxygen molecules on the surface of plutonium gallium system is hole-site vertical adsorption with the adsorption energy size of 10.7 eV. The bonding between oxygen atom and surface is mainly due to the overlapping hybridization of Pu-6s, Pu-7s, Pu-6d, Ga-3d and O-2p orbitals. Oxygen molecules mainly interact with the atoms of the first layer on the surface of the plutonium gallium system. The oxygen atoms after stable adsorption are able to diffuse to the subsurface of the plutonium gallium system after overcoming the energy barrier of 16.7 eV and form a stable structure. The research results reveal the initial reaction process and adsorption law of oxygen on the surface of plutonium gallium system from microscopic level, which is helpful to further explore the surface corrosion prevention technology of plutonium gallium system and improve the reliability and safety of plutonium gallium alloy components.
为了深入理解氧在钚镓体系表面的吸附过程，并从理论层面揭示钚镓合金表面氧化腐蚀初期的化学反应机理，采用基于密度泛函理论的第一性原理方法研究了氧分子在钚镓体系表面的吸附行为。结果表明，表面氧分子吸附在钚镓体系表面并解离为两个原子态时，分子键长增加并最终断裂。氧分子在钚镓体系表面最可能的吸附位置是孔位垂直吸附，吸附能大小为10.7 eV。氧原子与表面之间的键合主要是由于Pu-6s、Pu-7s、Pu-6d、Ga-3d和O-2p轨道的重叠杂化。氧分子主要与钚镓体系表面第一层原子相互作用。稳定吸附后的氧原子在克服16.7 eV的能垒后能够扩散到钚镓体系的次表面并形成稳定结构。研究结果从微观层面揭示了氧在钚镓体系表面的初始反应过程和吸附规律，有助于进一步探索钚镓体系的表面防腐技术，提高钚镓合金部件的可靠性和安全性。
