Deposition of Diamond-Like Carbon on Inner Surface by Hollow Cathode Discharge

摘要

A cylindrical hollow cathode discharge(HCD) in CH4 /Ar gas mixture at pressure of 20-30 Pa was used to deposit diamond-like carbon(DLC) films on the inner surface of a stainless steel tube. The characteristics of the HCD including the voltage-current curves, the plasma images and the optical emission spectrum(OES) were measured in Ar and CH4 /Ar mixtures. The properties of DLC films prepared under di?erent conditions were analyzed by means of Raman spectroscopy and scanning electron microscopy(SEM). The results show that the electron excitation temperature of HCD plasma is about 2400 K. DLC films can be deposited on the inner surface of tubes. The ratio of sp3/sp2bonds decreases with the applied voltage and the deposition time. The optimizing CH4 content was found to be around CH4 /Ar =1/5 for good quality of DLC films in the present system.