Exploring the incorporation of nitrogen in titanium and its influence on the electrochemical corrosion resistance in acidic media

The role of the nitrogen incorporation into titanium, its chemical nature, the location in the titanium lattice and its electrochemical performance were investigated by a combination of several spectroscopy and microscopy techniques using samples prepared by CVD of NH₃ at different temperatures and successive electrochemically tested in 1 M of HClO₄. We found that nitrogen is incorporated in either the interstitial or substitutional site of the lattice depending on the preparation temperature modifying strongly its corrosion resistance which was ascribed to the N 2p hybridization with the Ti 3d orbitals. It was found that at low temperature the N 2p orbitals were more likely to hybridize with Ti_3d-t_2g orbitals while higher temperature favors the hybridization with the Ti_3d-e_g orbitals. This is responsible for the corrosion resistance shown by the samples prepared at higher temperature.