Structural and Corrosion Properties of NiPx Metallic Glasses: Insights from EIS and DFT

Despite the increasing interest in metallic glasses for a variety of engineering applications, the structure and corrosion properties still remain unknown. In particular, these properties for Ni–P alloy, a typical metallic glass, are greatly dependent upon the phosphorus content in the alloy. In this report, a relationship between the structural property and the interface corrosion behavior of Ni–P alloys was studied when phosphorus content was intentionally tuned. DFT calculation and EIS measurement were used to determine the electronic structure property and corrosion behavior of Ni–P alloy in acidic Au(III) solution that is applied to the immersion gold process of electroless deposited Ni–P alloys in the manufacture of printed circuit boards. The results indicate that the doped phosphorus atoms are able to bind electrons and change the structure of Ni–P alloy from the metallic to ceramic state, thereby avoiding an overetching in the solution. Theoretical calculation predicts that the anticorrosion ability of Ni–P alloy will be enhanced with phosphorus content. This is in good agreement with experimental data obtained in this work.