CORROSION STABILITY OF TIN PREPARED BY ION-IMPLANTATION AND PVD

Thermodynamic U/pH diagrams for TiN were calculated which predict only a small range of stability in alkaline solutions. In contrast, electr ochemical experiments in solutions of different pH values show high st ability against oxidation and reduction. The properties of TiN layers were investigated by potentiodynamic, potentiostatic and open circuit experiments. The observations were compared to results from XPS. Corro sion measurements with nitrogen implanted Ti revealed corrosion resist ance even in hot concentrated acids. This feature could not be found f or TiN prepared by physical vapour deposition. The higher corrosion ra tes of PVD samples in contrast to layers formed by ion implantation re fer to their columnar structure. Subsequent ion implantation of TiN-PV D decreases the current densities by a factor of 10.