H和B原子在有序态Ni_3Fe表面的吸附

Effect of Electronic Structure on Adsorption of H and B Atoms on Ordered Ni_3Fe Surface

采用基于密度泛函理论(density functional theory,DFT)的第一性原理方法,对H和B原子在有序态Ni3Fe合金(111)表面的吸附进行研究.结果表明,B原子在有序态Ni3Fe合金(111)表面的吸附能远低于H原子,从而更容易被有序态Ni3Fe合金(111)表面吸附,形成稳定结构.这导致H原子在有序态Ni3Fe合金表面的吸附机会大大减少,降低了有序态Ni3Fe合金在氢气中的环境氢脆.进一步的电子结构分析表明,H原子的表面吸附能高于B原子是由于H原子在有序态Ni3Fe合金(111)表面吸附时,H原子的反键态被推到了费米面以上所引起的.

This paper performs first-principles calculations based on the density functional theory （DFT） to investigate the interaction of H and B atoms with ordered Ni3 Fe （ 111 ） surface. The results showed that the B atom can be strongly absorbed onto the surface, and absorption energies of B atoms are much lower than that of H atoms. It indicates that the B atom can be easily bound by the ordered Ni3Fe surface, which occupies the suitable site and inhibits the access of H into the matrix. Furthermore, electronic structure analysis is presented to understand that the adsorption energy of H atom higher than that of B atom is accrediting to its anti-bonding state being pushed up to the Fermi level when an H atom is absorbed on the （111 ） surface of the ordered Ni3 Fe.