Evidence of surface migration and formation of catalytically “inactive” Pt in corrosion studies of Pt+ implanted Ti

This investigation is part of an ongoing research project directed at applying the techniques of ion implantation doping and ion scattering analysis to identify the mechanisms associated with the anodic dissolution of TiPt alloys. The TiPt alloys produced by ion implantation were electrochemically examined in hydrogen-saturated 1N H₂SO₄ by both potentiostatic polarization and open-circuit potential methods. In this study, Ti samples implanted to relatively high doses (5.4 × 10¹⁵ −2.9 × 10¹⁶ atoms/cm²) were examined by ion scattering analysis at various stages in the electrochemical measurements. Quantitative measurements showed that the majority of the implanted Pt accumulated on the surface during anodic dissolution and underwent large scale surface migration. Evidence is also presented for the transition of the Pt on the surface from a catalytically “active” to “inactive” state. Possible mechanisms for the observed catalytically “inactive” Pt are discussed.