Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (12): 2519-2523.doi: 10.3866/PKU.WHXB20091115

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Prediction of the Surface Segregation of Trace Elements on the Al(100) Surface by Density Functional Theory

LIU Jian-Cai, ZHANG Xin-Ming, CHEN Ming-An, TANG Jian-Guo, LIU Sheng-Dan   

  1. Key Laboratory of Non-Ferrous Metal Materials Science and Engineering, Ministry of Education, School of Materials Science and Engineering, Central South University, Changsha 410083, P. R. China
  • Received:2009-05-26 Revised:2009-07-17 Published:2009-11-27
  • Contact: ZHANG Xin-Ming E-mail:xmzhang_cn@yahoo.cn

Abstract:

A simplified 9-layer slab model was created using periodic density functional theory calculation to predict the tendency of trace elements to undergo surface segregation. Using this approach, nine different trace element atoms (Fe, Si, Mg, Cu, Mn, Ga, In, Sn, and Pb) were substituted into the (100) plane in a pure aluminumfoil surface and the surface segregation energies were calculated. The results were in very good agreement with the available experimental data. There were various correlations between the segregation energy and the relaxed position on the surface of the substituted atom, the radius of the substitute atom and the experimental surface energy of the metal. A negative segregation energy indicated that the trace element atoms were able to segregate and move to the surface while a positive segregation energy implied a tendency to move into the bulk material. Trace element atoms segregated on the Al foil surface and led to many defects and dislocations which can increase initial pitting nucleation sites and enhance the density of pitting for Al foils.

Key words: Density functional theory, High purity aluminumfoil, Surface segregation, Surface energy

MSC2000: 

  • O641