SiOx Top Layer on DLC Films for Atomic Oxygen and Ozone Corrosion Protection in Aerospace Applications

Abstract

Every year, billions of dollars are invested in research and development for space applications, including new systems, new technologies, and new materials. DLC (Diamond-Like Carbon) is a promising material for use in these applications, but its use faces a technological barrier, since it is severely etched by atomic oxygen and ozone. In this study, SiOx-DLC thin films were deposited as a top layer of diamond-like carbon (DLC) films on Ti-6Al-4V substrates to increase resistance against corrosion by atomic oxygen and ozone as well as meet the requirements for use in Low Earth Orbit (LEO) satellites. The corrosion resistance of the films was evaluated using oxygen plasma, and the tribological and mechanical properties were investigated. The SiOx-DLC top layer reduced the corrosion rate two orders of magnitude and increased the critical load from 16.2 ± 1.5 N to 18.4 ± 0.4 N.

A review on diamond-like carbon-based films for space tribology

“…To alleviate the damage of AO radiation, oxyphilic elements with pony-sized particles are added into the DLC films with a uniform distribution. The main method to prevent AO radiation was doping oxyphilic elements into the film and forming a corresponding oxidising layer of high quality on the outermost surface as a consequence of preventing the interior from being oxidised, as shown in Figure 9 [94][95][96]. Ji et al [97] proved that Mo nanocomposites could preserve the COF of approximately 0.01 and wear rate of 1.8 × 10 −8 mm 3 /N m of DLC films after AO radiation.…”