Plasma analyses and structural properties of Cr-N-C-O coatings synthesized by a cathodic arc evaporation process

Recently, nanocomposite coatings have attracted much interest because of their excellent mechanical performance and chemical stability. In this study, Cr-N-C-O nanocomposite coatings were synthesized by cathodic-arc evaporation with plasma enhanced duct equipment. Nitrogen and CO2 reactive gases were introduced to react with chromium to form Cr-N-C-O nanocomosite coatings during the deposition process. The plasma in a cathodic arc evaporation process used for the deposition of Cr-N-C-O coatings was studied by an optical emission spectrometer (OES). With the introduction of nitrogen and CO2 reactive gases into the chamber, high density of evaporated chromium catalyzes the decomposition of nitrogen and CO2 reactive gases, and induces the formation of Cr-N-C-O films. The emission intensity of Cr atoms decreased with increasing N2/(N2 + CO2) flow rate ratio. It showed the deposition rate increased at higher CO2 flow rate. A nanocomposite structure of coexisting CrN, Cr2N and Cr2O3 crystallites and amorphous carbon phases was found in the Cr-N-C-O coatings.