Efficient prediction of corrosion behavior in ternary Ni-based alloy systems:Theoretical calculations and experimental verification  

作　　者：Xuelian Xiao Keke Chang Kai Xu Ming Lou Liping Wang Qunji Xue 

机构地区：[1]Key Laboratory of Marine Materials and Related Technologies,Zhejiang Key Laboratory of Marine Materials and Protective Technologies,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China [2]Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Journal of Materials Science & Technology》2023年第36期94-106,共13页材料科学技术（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(No.U21A20127);Excellent Young Scientists Fund of National Natural Science Foundation of China(NSFC),No.52222507);the Natural Science Foundation of Ningbo City(No.2022J304).

摘　　要：Pourbaix diagrams are calculated to describe electrochemical processes for alloys in aqueous solution.With the multi-component differentiation of alloy systems,the construction of Pourbaix diagrams is fac-ing challenges,especially for non-single-phase alloy systems.In this study,the simultaneous construction of phase diagrams and Pourbaix diagrams were implemented for predicting the evolution of the phases in the immune and passive regions.The CALPHAD(CALculation of PHAse Diagram)approach was used to quickly access the Gibbs free energies of various phases and the chemical potential of the elements in the phases from the thermodynamic database of the Ni-Si-Al-Y system.The corrosion behavior of two typical Ni-Al-Si and Ni-Al-Y systems was investigated.Si and Y were added to Ni-based alloys to produce the solid solutions L12-Ni_(3)(Al,Si)and L12-Ni_(3)Al+Ni_(5)Y,respectively.Calculations showed that NiO and Al_(2)O_(3)make up the passive area of the Ni_(3)Al 1 alloy.The introduction of SiO_(2)and Y(OH)3 in the passive region separately helped to minimize the alloys’susceptibility to corrosion.However,Si reduced the thermody-namical possibility of NiO for mation in the passive film,and the addition of Y caused extreme galvanic corrosion.Experiments on Ni-based alloys validated the results through electrochemical corrosion.It was also discovered that the presence of Ni_(5)Y produced galvanic corrosion and that Si reduced the oxide in the passive film,causing pitting corrosion.The corrosion prediction of the quaternary alloys indicates that the solid solution of Si in Ni_(5)Y reduces the galvanic corrosion effect and the dissolution of passive film.The current work demonstrates that phase diagrams and Pourbaix diagrams may be efficiently and accurately predicted using a well-constructed thermodynamic database,which has major implications for future studies on the corrosion behavior of multi-component alloys.

关 键 词：Pourbaix diagrams CALPHAD Ni-based alloys Passive film 

分 类 号：TG172[金属学及工艺—金属表面处理]