Combining magnetic filtered cathodic arc deposition with ion beam sputtering to afford superhard TiSiN multilayer composite films with tunable microstructure and mechanical properties

A series of superhard TiSiN multilayer composite films were prepared on silicon wafer by combining magnetic filtered cathodic arc deposition with ion beam sputtering. As-prepared multilayer composite films were characterized by means of high-resolution transmission electron microscopy, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, and their mechanical properties such as hardness, adhesion strength and wear resistance were evaluated as well. It was found that as-prepared TiSiN multilayer composite films, consisting of six sub-layers of alternately deposited crystal phase TiSiN solid solution and TiSiN solid solution/α-Si3N4 composite, and with sub-layer hardness increased from 23 to 26 GPa to the surface, exhibit extremely high hardness (>40 GPa) as well as good adhesion strength and wear resistance. Besides, the microstructure and mechanical properties of TiSiN sub-layers vary with varying Si content in the sub-layers, and varying Si content in the sub-layers leads to changes in the crystal lattice parameters of TiSiN solid solution at the inter-sub-layer interfaces thereby generating internal stress field to block dislocation movement and crack propagation. This means that the present approach could be of special significance in developing high-performance TiSiN multilayer composite films, since, based on the elaborate design of the sub-layers and the proper adjustment of the deposition conditions, it provides the feasibility to well manipulate the microstructure and mechanical properties of TiSiN multilayer composite films even under relatively low levels of deposition temperature and ion energy.