Fe-Al金属间化合物抗腐蚀性能的密度泛函研究  

A Study on the Corrosion-Resistance of Fe-Al Intermetallic Compounds by DFT

作　　者：尹衍升 于帅芹[1] 张伟伟[1] 陈守刚[1] 

机构地区：[1]中国海洋大学材料科学与工程研究院,山东青岛266100

出　　处：《中国海洋大学学报（自然科学版）》2008年第4期657-662,共6页Periodical of Ocean University of China

基　　金：国家自然科学基金重点项目(50672090);青岛市将才计划(05-2-JC-76)资助

摘　　要：应用BPW91/Lanl2dz/6-31g(d)方法深入研究Al原子掺杂Fen(n≤8)团簇的基态结构和稳定性,获得较为准确的几何信息。为了消除基组误差,在Lanl2dz/6-31g(d)混合基组优化结构的基础上,应用全电子基组(6-311++g(2d,2p)进行单点计算,获得的能量与该基组全优化结果一致。通过计算发现1个Al原子很难掺杂到铁团簇结构的中间,倾向于分布在铁簇的表面,并且它的掺杂也难以改变铁簇的主体结构。对Fen-1Al团簇进行稳定性分析,二级能量差分、HOMO-LUMO能隙以及垂直电离势都一致表明Fe3Al具有特殊的稳定性。而Fe3Al金属间化合物具有优异的抗氧化、抗硫化以及耐海水等腐蚀性能,很好地支持了作者的理论结果。因此,应用密度泛函方法获得的量化参数能从原子、分子角度反映Fe-Al合金的耐腐蚀性能。We present the ground state and electronic properties of Al-doped Fen （ n≤8） clusters using the BPW91/Lanl2dz/6-31G（d） method, which can be used to obtain accurate geometric information. In order to eliminate basis set errors, single-point BPW91/6-311 ＋ ＋ G（d, p） calculations are performed for all the structures using the geometries obtained from the BPW91/lanl2dz//6-31g（d） optimizations. Furthermore, the single-point BPW91 calculations for Al-doped Fen （ n = 2 - 4） are very close to those obtained by the fully optimized BPW91 results. Calculated results show that an Al atom tends to reside in the caps or apexes rather than in the middle of the iron structures, in other words the doped Al atom prefers to be on the surface of the iron structures and not to change the frame structures of iron atoms. In addition, we analyse the unusual stability of Fen- 1Al clusters which was confirmed by the results of the second finite difference of the total energy and the HOMO-LUMO energy, The vertical ionization potential（VIP） shows the Fe3Al has special stability. For Fe3Al bulk material, a great many experiments have vertified that it has special corrosion-resistance, which is consistent with our theoretical results. Therefore, some quantitative parameters obtained by DFT can be used to characterize Fe-Al corrosion resistance at atom and molecular levels.

关 键 词：金属腐蚀 团簇 掺杂 电子结构 密度泛函理论 

分 类 号：P755.3[天文地球—海洋科学]