Formation of compounds by high-flux nitrogen ion implantation in titanium

Abstract

Polycrystalline titanium was implanted with nitrogen ions at energies from 30 to 60 keV and with doses from 1 × 1016 to 1.5 × 1018 N+-ions cm−2 at room temperature. The implanted titanium layers were investigated by high-voltage electron microscopy and transmission high-energy electron diffraction. The formation of titanium nitride, titanium carbonitride and titanium carbide phases were considered in relation to their dependence on nitrogen ion implantation dose. In the dose range from 1 × 1016 up to 1.5 × 1018 N+-ions cm−2 the cubic phase δ-TiN x was formed. In the dose range between 1 to 2.5 × 1017 and 1.5 × 1018N+-ions cm−2 the tetragonal phase e-Ti2N was found in addition to the δ-TiN x phase. The lattice structure of these titanium nitride phases is a function of the nitrogen ion implantation dose. Additionally, the presence of titanium carbonitrido TiC y O x and titanium carbide TiC y phases can be proved. The analysed titanium nitride, titanium carbUnitride and titanium carbide phases are represented in a state diagram as a function of implantation dose.