CARBON NITRIDE FILMS PREPARED AT DIFFERENT N2/Ar RATIOS BY CLOSED FIELD UNBALANCED REACTIVE MAGNETRON SPUTTERING
CARBON NITRIDE FILMS PREPARED AT DIFFERENT N2／Ar RATIOS BY CLOSED FIELD UNBALANCED REACTIVE MAGNETRON SPUTTERING

Carbon nitride (CNx) thin films have been deposited onto Si(100) (for structural and mechanical analyses) and M42 high-speed-steel (for tribological measurement s) substrates at room temperature by closed-field unbalanced magnetron sputterin g. The mechanical and tribological properties of these films were highly depende nt on the N/C concentration ratio that was adjusted by the F(N2)/F(Ar) flow-rate ratio at fixed substrate biasing of -60V during deposition. The films were char acterized by employing scanning electron microscopy (SEM), atomic force microsco py (AFM), nano-indentation measurements, X-ray photoelectron spectroscopy (XPS), Raman scattering and Fourier transform infrared (FTIR) spectroscopy, pin-on-dis c tribometer, scratch tester, and Rockwell-C tester. The results showed that the N content in the films increased with the N2 pressure. However, the maximum N/C ratio obtained was 0.25. The nanohardness was measured to be in the range of 11 .7-20.8GPa depending on the N/C ratios. The XPS N 1s spectra showed the existenc e of both N-C sp2 and N-C sp3 bonds in films. Raman and FTIR spectra exhibited t hat N-C bonds were fewer when compared to other N-C bonds. The friction coeffici ent of the film deposited onto steel substrate with N/C=0.26 was measured to be ~0.08 and for film with N/C=0.22 a high critical load of 70N was obtained. The t ribological data also showed that the wear rates of these films were in the rang e of ~10-16m3/Nm, indicating excellent wear resistance for CNx films.