Study On Deposition Of C/SiC Films On Steel Substrate By Magnetron Sputtering

C/SiC films with excellent wear resistance and low friction coefficient were deposited on the primary substrate of GCr15 steel by magnetron sputtering. Deposition steps were as follows: first, silicon carbide film was deposited on the substrate by R.F. magnetron sputtering at room temperature and heat to a given temperature, respectively. Then thin amorphous carbon film was deposited on SiC film by D.C. magnetron sputtering.Structures of the films were analyzed by X-ray diffraction and Raman spectra. The results showed that the SiC film deposited on room temperature was typical amorphous, while partial crystalline films were obtained at high substrate temperature. But wellβ-SiC crystalline form could be obtained in the C/SiC films while silicon carbide film was deposited at Ts of 500℃. The Raman spectra showed the surface film was diamond like carbon (DLC) structure. Additionally, Single SiC film was annealed at high temperature in vacuum furnace. The XRD result showed the crystalline structure of the SiC initially formed up to 800℃, the film was dominatingβ-SiC while annealed at 1000℃, but the structure of the films which obtained by annealing were almost polycrystalline.Surface morphology of the film was analyzed with scanning electron microscope (SEM). It was observed that there was many defects existed in the film that was deposited at room temperature, and big SiC blocks existed in the film. The film deposited at high temperature was made up of small blocks with fewer defects. After the deposition of amorphous carbon, SiC layers were covered with compact amorphous carbon films. SiC blocks broke into small pieces when the annealing temperature was up to 800℃, small and evenly-distributed SiC crystals could be observed at 1000℃, but the crystals grew up at high annealing temperature of 1200℃, almost reached to 400～500nm.The adherence between the film and the matrix was measured with scratch test detector. The result showed that the films deposited at low argon pressure had high stress and it was easy to be cracked down. The adherence could be improved efficiently due to the film diffusion while increasing the substrate temperature. Because the surface of SiC film was rich in Si atoms, the SiC layer adhered well with carbon layer, the films were steps from SiC rich with Si to rich with carbon then to amorphous carbon film while increased carbon layer. The adherence could be improved significantly while induced Ni-P or Ti inter-layer, reached to almost 30N or even higher from primary 16N. Tribology performances of films were measured with friction and wear test detector. The friction coefficient of the SiC single film was 0.4～0.5 while the substrate was 0.8～0.9, and the friction coefficient of the C/SiC films decreased to 0.1～0.2. Micro-hardness testing result showed that the hardness of SiC single film could reach to 35Gpa.These results indicated that films had good tribology performances.