A study of surface composition on pure iron induced by pulsed laser drilling

The surfaces of micro-spots and of percussion-drilled micro holes made in iron by irradiation with a copper vapour laser in air were studied by means of AUGER electron spectroscopy (AES) and scanning electron microscopy (SEM). The enrichment of iron with nitrogen and oxygen was established for the micro-spots as well as for the micro holes. The chemical composition of the walls of the laser drilled holes did not significantly depend on the laser pulse repetition frequency varied between 10 Hz and 7 kHz whereas the amount of re-deposited material on the hole walls and the density of submicroscopic pores in the re-deposited material were found to be changing for different repetition frequencies.