Repetitively-pulsed nitrogen implantation in titanium by a high-power density ion beam

Abstract

The article presents the results of studies of the features and regularities of high-intensity nitrogen ion implantation into titanium using repetitively-pulsed beams with high average and pulsed power densities. It is shown that the method of low-energy high-intensity nitrogen ion implantation at current densities of 180, 140, 60, and 10 mA/cm2 makes it possible to obtain wide ion-doped layers in titanium. The regularities of changes in both thickness and elemental composition of ion-doped layers depending on the ion current density have been established. It has been established that a wide diffusion layer is observed at ion current densities from 60 to 180 mA/cm2. Nitrogen concentration in the diffusion layer increases with an increase in the ion current density. As a result of a long high-intensity implantation process at temperatures of 700 and 850 °C, the titanium microstructure deteriorates in the entire volume of the sample material. The article presents the transmission electron microscopy data showing that the modified layers at a depth of 10 μm consist of a-Ti, in the volume of which nanosized particles of d-TiN with average size of 15.4 nm crystallize. Numerical simulation is used to study the change in temperature fields in titanium under the action of a pulsed and repetitively-pulsed ion beam with submillisecond duration on the surface with a power density from 20 to 30 kW/cm2. The results of experimental studies of the pulsed impact of high-pulse ion beams on the titanium microstructure are discussed.