DLC film fabricated by a composite technique of unbalanced magnetron sputtering and PIII

DLC multilayer films were deposited on an AISI 304 stainless steel substrate by the composite technique of unbalanced magnetron sputtering and plasma immersion ion implantation (PIII). Structure characterization was performed on the films by Raman spectroscopy (RS) and Glancing X-ray Diffraction (GXRD). Composition analysis of the surface layer on the implanted substrates was carried out using auger electron spectroscopy (AES). The mechanical properties of the films were evaluated by nanoindentation. The results showed that the Raman spectra were divided into a "D" disordered peak and a "G" graphite peak with the integrated intensity ratio between them (I-D/I-G) being 1.30. The implanted carbon penetrated the substrate resulting in complete interfacial mixing. The hardness, elastic modulus, fracture toughness and interfacial fracture toughness of the films were about 19.84 GPa. 190.03 GPa, 3.75 MPa.m(1/2) and 5.68 MPa.m(1/2) respectively. Compared with that of a DLC coating deposited directly by the PIII technique, the interfacial fracture toughness of the multilayer films increased, which is mainly attributed to the interfacial mixing at the interface.