Wetting Behavior And Interfacial Properties Of Cu-Ti Alloy On AlN Surface

Ceramic materials have attracted attention due to their excellent properties,such as high mechanical strength,high thermal conductivity,wear resistance,low media consumption,and high temperature resistance.They have been widely used in aerospace,power electronics,life sciences,etc.The forming effect of ceramics is poor,and the connection of cermet can effectively solve this problem.The bonding performance of the metal and ceramic two-phase interface determines the performance of the metal/ceramic dissimilar material joint.However,due to their differences in physical and chemical properties,the bonding performance of the interface is affected by many factors;wettability is the most critical impact factor.Therefore,the research on the wettability of metal/ceramic systems becomes meaningful.The key to metal wetting ceramics is the active element.There are differences in the research on the wetting-promoting mechanism of active elements,so this subject uses first-principles calculations and Experiments are combined to explore the effect of Ti element on the Cu/AlN wetting system.This subject has conducted a detailed study on the bulk properties and surface stability of Cu,AlN and TiN.The surface energy of 4 layers of Cu(111)atoms,8 layers of AlN(001)atoms and 5 layers of TiN(001)atomic layers reaches a stable value.Polar surface AlN(001)surfaceN terminated andN'terminated surface energy with theN chemical potential change trend is opposite to the Al terminated,and theN'terminated has a lower surface energy,which can represent the surface properties of AlN ceramics.Based on the discussion of the surface properties,the Cu/AlN and Cu/AlN(H)interface models are established.The calculation shows that the Cu/AlN interface adhesion work is higher than the test results.The Cu/AlN(H)adhesion work keep it low.Two different doping models of Ti atoms are constructed:(1)When 4 Ti(equivalent to 7.4at.%Ti)atoms replace H atoms on the AlN surface,the interface adhesion work is1.01J/m²,which is compared with The unaffected interface adhesion work of Ti atoms is greatly improved;the electronic structure of the interface shows that the metal bond between Ti atoms and Cu atoms is the key to the improvement of the interface adhesion work;when the adsorption of Ti atoms reaches 9(equivalent to 15.3at.%Ti)Adhesion work will further increase to 1.66 J/m²;(2)When Ti atoms are doped on the Cu interface side,this doping state has a limited effect on the improvement of adhesion work,and 3 Ti atoms doped When the interface adhesion work is 0.13J/m²,the effect of the electronic structure display interface is weak.The interface model of Cu/interface products is constructed:(1)The electronic structure of the interface between Cu/TiN interface model shows that Ti atoms in TiN are the key to interface bonding,and strong hybridization is formed between Cu and Ti atoms,which makes adhesion The work is up to 0.67J/m²;(2)In order to construct the Cu/TiNx interface model,N atom vacancies are constructed at the interface.The electronic structure shows that the existence of N vacancies intensifies the electron transfer between the interfaces,and the adjacent Cu atoms become the charge transfer the main body,which increases the interfacial adhesion to 0.86 J/m²,the presence of N vacancies strengthens the interfacial bonding.Based on the law of the effect of Ti atoms on the Cu/AlN interface,the wetting behavior of Cu-Ti alloy solder on the AlN surface was studied.Low content of Ti cannot effectively reduce the wetting angle,and 7at.%Ti reduces the wetting angle to 92°;The reaction layer is divided into dense area,incompletely dense area,and granular area.The reaction product is analyzed as TiN;using the adsorption Gibbs free energy formula,it is estimated that only 8.67×10¹⁶/cm² of Ti adsorption is needed to make Cu/AlN the state of the interface changes greatly;the adsorption energy of Ti atoms calculated by the static adsorption model is negative,indicating that Ti atoms are easily adsorbed by the interface.