Effects of SiOx-incorporation hydrocarbons on the tribological properties of DLC films

The effects of hexamethylsiloxane (HMDSO) reactants are studied on the adhesion and tribological properties of DLC films deposited directly on steel and Cr substrates. A 13.56-MHz magnetically confined inductively coupled plasma (ICP) system has been applied to deposit diamond-like carbon films using CH, and Si-containing hydrocarbon reactant with bipolar-pulsed substrate bias. The RF power is varied from 100 W to 400 W and the substrate bias is varied in the range of 100-400 V to obtain films of different sp(2)/sp(3) carbon ratios. The films are deposited on Si, nitriding SKD11, and Cr-plated SKD11 substrates. By employing CH, reactant, the quality of DLC films is optimized at an RF power of 200 W and a substrate bias of 300 V on Si as indicated by Raman spectra. However, DLC films cannot be deposited directly on steel substrates. Only disintegrated graphite-like powders are observed on steel. By employing HMDSO reactant containing Si and O atoms, a-C:H/SiOx films can be deposited directly on steel substrates with very good adherence. XPS results indicate that carbon is bonded to carbon only and silicon is bonded to oxygen only. No bonding between C and Si is observed. TEM is being further employed to characterize the microstructure to identify if SiOx nanoparticles are formed in the DLC matrix. The films deposited directly on steel using HMDSO show good wear behavior. (C) 2001 Elsevier Science B.V. All rights reserved.