Fabrication And Tribological Property Of Low Friction Cofficient DLC Films

Plasma immersion ion implantation and deposition with variable pulse voltage and frequency was used to fabricate the duplex DLC films. And H2 and N2 gas were introduced to fabricate the H doped and N doped DLC films, respectively.Raman spectra, FTIR spectra and XPS were used to evaluate the structure of the as-deposited DLC films. Ball-on-disc test was used to evaluate the tribological properties of DLC films and SEM was used to observe the surface morphology. In addition, HV hardness was determined.The inert stress is essential for the mechanical properties of the as-deposited DLC film and most failure of films is attributed to the high inert stress and low adhesion. In this study, the simple duplex strengthening multilayer structures with variable voltage and pulse frequency were used to release the stress and improve the adhesion. The duplex treatment with the implantation voltage of 30 kV and deposition voltage of 3 kV shows the best tribological property, and the multilayer structure by the duplex treatment has a important effect on the property.During the doping experiments, the DLC films with the variable hydrogen content were fabricated by change the ratio of C2H2 to H2. In the range of experiment parameters, the hydrogen content in the film decreased with the increase of H2 ratio. The fabricated hydrogenated DLC film with low hydrogen content shows the better tribological property than that with high hydrogen content in the atmosphere, however, the dependence of hydrogen on the tribological property shows the contrary result in the nitrogen environment. The effect of hydrogen content on the hardness of film is not obvious, but with the increase of hydrogen content, the adhesion becomes poor due to the increase of inert stress.In addition, to improve the adhesion and decrease the stress, N doping was conducted to fabricate the film. With the increase of N2 ration in the mixed gas, the N content in the film was increased, and the adhesion was improved, but the hardness was decreased. In the atmosphere, the film with high N content shows...