Effect of the energy of hydrocarbon ions on diamond-like carbon films deposited on alumina microparticles through repeated pulsed discharge in hollow cathode with methane gas

Abstract

The Diamond-like Carbon (DLC) modified alumina microparticle is expected to be an ideal filler which can greatly improve the thermal conductivity of the epoxy-alumina composites with high fill factor, meanwhile the composites can still maintain high dielectric properties. Plasma Enhanced Chemical Vapor Deposition (PECVD) has been mostly used to prepare DLC film on bulk material and the ion energy in the plasma shows crucial influence on the properties of the DLC, while properties of the DLC on solid microparticle prepared through PECVD method as well as the effect of the ion energy are still unclear. In this paper, DLC on alumina microparticle has been prepared through a high-efficient method of repeated pulsed hollow cathode discharge in methane gas and characteristics of the DLC on alumina particle has been studied and analyzed. The morphology and bond composition of DLC on particles has been studied through electron microscopy, Raman spectrometer and X-ray photoelectron spectroscopy. The ion energy distribution in the discharge plasma has been diagnosed and used to analyzed its effect on the hybrid bond content of the DLC through correlation analysis. Correlation of the ion energies and the hybrid bonds content of the DLC shows hydrocarbon ions in the discharge plasma with energy of 100~200 eV present most benefit to the formation of the sp3 hybrid bond content of DLC film on alumina microparticle and hydrogen ions with energy of 700~1000 eV are also beneficial to improve sp3 hybrid bond content of the DLC film.