Femtosecond Pulsed Laser Deposition of Chromium Diboride-Rich Thin Films

Abstract

Chromium borides are promising candidates for several structural applications including protective coatings for materials exposed to corrosive and abrasive environments. In this paper the pulsed laser deposition of chromium diboride-rich thin films has been carried out in vacuum by using a frequency doubled Nd:glass laser with a pulse duration of 250 fs. The films have been deposited at different substrate temperatures and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. Lastly, the film’s hardness has been studied by Vickers indentation technique. The results indicate that only the films deposited at a substrate temperature of 500 °C are crystalline and formed by chromium diboride, together with a certain amount of boron and chromium, which suggests that, as main mechanism, a process taking place on the surface from atoms and ions from the gas phase. This hypothesis has been confirmed by the study of the plasma produced by the ablation process.