Structure Design And Surface Characteristics Of Copper-nickel Alloy

Copper-nickel(Cu-Ni)alloy is a widely used binary alloy.It has many advantages,such as high temperature resistance,corrosion resistance,easy processing and so on.Based on the first-principle method of density functional theory,this paper studies the influence of atomic arrangement of Cu based binary alloy on the energy change,physical properties and surface properties of the alloy.The main progress of this paper is as follows:1.We have constructed copper-nickel alloy models with different alloy proportions,and set up two different internal atomic position structures:the layered segregation structure with two kinds of atoms occupying different atomic layers and the homogeneous mixed structure with two kinds of atoms uniformly distributed.We systematically studied the influence of different arrangement of Cu and Ni atoms on their formation energy.The results show that as Cu atoms take the majority in the alloy structure,the two kinds of atoms in the alloy tend to occupy different atomic layers,thus forming a layered segregation structure.However,when most of the atoms in the alloy are Ni atoms,the two atoms tend to be evenly arranged,thus forming a uniform Cu-Ni mixed structure.2.Based on the structure model of Cu-Ni alloy,the surface properties of Cu-Ni alloy are further studied.The results show that the work function values of Cu-Ni alloy atoms fluctuate greatly in the process of changing from homogeneous mixed structure to layered segregation structure,which shows that the distribution characteristics of Cu and Ni atoms have certain influence on its surface properties.The work function values of the two surfaces of layered segregation and uniform arrangement can be changed At0.1e V,the surface work function of Cu-Ni is lower,which means that it has better electronic excitation performance.At the same time,for the same proportion alloy,the work function follows the order of(111)>(100)>(110).Furthermore,the surface density of States and its d-band center position?_d for different surfaces are studied.It is found that the surface catalytic activity follows the order of(111)<(100)<(110).3.Based on the above-mentioned surface model of Cu-Ni structure optimization,CO gas was selected as the adsorption molecule to study the surface catalytic characteristics of different sites on the different Cu-Ni alloy models,and the interaction of adsorption sites on the surface characteristics of electron charge transfer,bonding and so on.The results show that the electron transfer is closely related to the adsorbed atom,and the free electron bond between CO and the alloy metal surface is formed during the adsorption process.In conclusion,based on the first-principle calculation method of density functional theory,this study systematically studies the influence of the arrangement law of Cu and Ni atoms in Cu-Ni alloy on the regulation of surface characteristics,analyzes the stability of different atom distribution structure of Cu-Ni alloy and its surface adsorption characteristics,which will provide theoretical guidance for the design of new binary alloy structure and the application of surface catalysis and sensor.