The Monte Carlo Simulations Of Surface Segregation Of The Pd Based Alloys

An ideal crystal is made up of many repeated structure units,which have the same configuration and inhabited periodicallyin the lattice of crystal. However, the commons is not like that,they have the boundary, and the boundary is the place march withdifferent materials and usually named as surface or interface.In a true word, it has included the outside and inner surface.It is the interface of solid materials and gases or liquid. Itis closely related the friction, abrasion, oxidation, erosion,segregation, catalysis and adsorption phenomenon. Theinterface is the field usually contains some atom-layers width,and the compositions of these layers are usually different fromthat of the bulk layers. Once the surface component of oneelement of the alloy differs from its bulk's ones, it is calledsurface segregation; and if the arrangement of surface atomsdiffer from bulk ones, it is called reconstruction orrelaxation. The researches of the alloy surface or interfacewill reveal many essential phenomenon of the real world. Theseresearches are not only a theory study, but also a driving forceof construction of present country. The surface science has astrong character of theory, including physic, chemistry,biology, material and many other aspects. It also relate topracticality. Thus it becomes one of the fastest developing andwidest application sciences.Having been brought forward by Zhang Bangwei, the modifiedembedded-atom method has been utilized by many people incalculating various properties of different alloys. One of themis H.Q. Deng, he makes a systematic research about the surfacesegregations of binary alloys. Their researches are concentratedon the Pt and Al based alloys. For example, Pd-X(X=Pd,Ir,Rh, Ru), Al-X(X=Fe,Mg). After synthetical analyzing and readingmany literatures, we decide that centered our works on the Pdbased alloys. Furthermore, besides to complete the surfacesegregation data of Pd based alloys, we further expanded thistheory in its application in the surface segregations ofternary ones. Using a suitable energy model and calculating thesurface component of ternary or even multicomponent alloys isa new branch of present surface research field. The presentresults indicate that the MAEAM is applicable in both binaryand ternary alloys, although it has never used particularparameters. It is convenient for realization.