2015 Volume 40 Issue 4 Pages 363-368
We investigated the effect of hyperthermal atomic oxygen beam irradiation on hydrogenated Si-doped Diamond-Like Carbon (hydrogenated Si-DLC) films for the purpose of use as a solid lubrication material in space. We found that film thickness of hydrogenated Si-DLC was constant after the exposure to atomic oxygen beam. From this result, the hydrogenated Si-DLC films have resistance to etching by the irradiation of atomic oxygen, unlike hydrogenated non-dope DLC films. In addition bulk composition of hydrogenated Si-DLC film kept constant. Especially, hydrogen content in Si-DLC film did not decrease. Therefore, hydrogenated Si-DLC film is expected to keep low fiction properties in a vacuum. Furthermore, the atomic oxygen beam fluence dependence of X-ray Photoelectron Spectroscopy (XPS) and Near Edge X-Ray Absorption Fine Structure (NEXAFS) spectra of hydrogenated Si-DLC films were measured. From these studies, it was found that the C atoms on the hydrogenated Si-DLC surface were desorbed, but Si atoms were remained on the hydrogenated Si-DLC surface as the SiOx by the collision of atomic oxygen. This SiOx layer was considerable to disturb the erosion of bulk film against atomic oxygen. From the element distribution in depth direction, it was found that the thickness of SiOx was about 5 nm.
