Progress report - ESR 11: Abqaat Naseer

date: May 17, 2022

category: News

New self-lubricating, anti-wear, corrosion-resistant coatings for reducing lubricant consumption in mechanical parts

Silicon doped diamond-like carbon coatings are well known for their excellent tribological properties and high thermal stability. While, previous studies established that the presence of oxygen dictates the surface properties of these coatings, the effect of oxygen content or O/Si ratio on properties of diamond-like carbon coatings has not been explored in detail. This gap can partially be attributed to the fact that these coatings are conventionally deposited using chemical vapor deposition pathways involving a complex decomposition process of Si-O containing precursors, hence limiting the precise control of dopant concentration in the final coating. This study reports development of silicon and oxygen doped diamond-like carbon coatings by reactive magnetron sputtering. The silicon (0 – 30 at. %) and oxygen (3.2 – 20 at. %) contents in the coatings were varied by controlling the power supplied to the silicon target and oxygen gas flow, respectively. In the case of oxygen-free coatings, silicon content increases linearly with the power supplied to the target. While, for oxygen-containing coatings, a linear relationship between O/Si ratio and oxygen flow/silicon target power, was observed. The hardness of the coatings increases with increasing silicon content while the introduction of oxygen generally resulted in comparatively lower hardness values. A similar trend was observed for the surface energy values of these coatings. The findings of this study will help in the selection of suitable coating stoichiometry for achieving desired coating properties of silicon and oxygen doped diamond-like carbon coatings.