Irradiation-induced intermixing effects at the interfaces of titanium and titanium-dioxide thin films and Fe-12%Cr substrate

Irradiation-induced compositional and structural changes at the interfaces between Fe-12%Cr binary alloy substrate and thin films of titanium and titanium-dioxide have been investigated. Irradiations were performed with 5 MeV Ni2+ ions at 300 °C and 500 °C, up to damage levels of 35 dpa (displacements per atom). For the 300 °C irradiation case, irradiation enhanced the interdiffusion coefficient by a factor over twenty for the titanium film samples, but by a factor of only 1.2 for the titanium dioxide film samples. At 500 °C, significant intermixing was observed in the titanium film samples and resulted in the formation of a wide Fe2Ti reaction zone. For the titanium dioxide film samples, chromium was observed to diffuse into sub-stoichiometric regions of the film. Irradiation caused the formation of chromium-rich nanoprecipitates within the oxide film and promoted a phase transformation in the film from anatase TiO2 to the Ti2O3 phase.