Effects of irradiation with low-energy and high-energy krypton ions on the structure of TiCrN coatings

Abstract

The results of surface structure investigations of TiCrN coating on carbon steel after irradiation by highand low energy krypton ions and successive two-hour vacuum annealing are reported in the present publication. Specimens with the TiCrN coatings of the 50-100 nm thickness were formed by vacuum arc deposition techniques. The prepared specimens were irradiated by low energy (280 keV) and high energy (125 MeV) krypton ions. Study of surface structure was done by scanning electron microscopy and atomic force microscopy. X-ray diffraction and the Rutherford backscattering spectrometry were applied for determination of structure and coating thickness. After irradiation by high energy Kr ions there appear convexities of spherical shape with dimensions 10-30 nm on the surface of the coating. Subsequent two-hour vacuum annealing led to decrease of convexities dimensions. Irradiation by low-energy Kr ions does not lead to significant changes in the structure of the coating surface. Only traces of surface sputtering are found. Explanation of the observed surface damage is proposed. Convexities are the traces of ions passing through coating and appear due to structural reconstruction at energy release along a trajectory of ions braking. As the projective range of high energy Kr ions exceeds coating thickness, then damage of structures is generated in the substrate and convexities are the traces of undersurface damages.