Search

Abstract: This work attempts to reveal the microstructure of interface and the relation between interface mixing and hardening mechanism in TiN/CNx multilayer films. The growth and microstructure of these interfacial layers are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Investigation result indicates that the interface species are mainly composed of Ti–C–N, the growth of interlayer mainly depends on the deposition temperature. The thickest interlayer (about 2.5nm) is produced at 300°C, and the interlayer disappears at 500°C. Nanoindentation testing indicates that the film with a maximum interlayer thickness of about 2.5nm exhibits superhardness up to 40GPa. Based on the experimental results, it is suggested that the interfacial intermixing and the crystal quality of TiN are the main reasons for the superhardness effect in TiN/CNx nanostructured multilayers. [ABSTRACT FROM AUTHOR]

a-C/a-C:Ti multilayer films were deposited on medical Ti6Al4V alloy using a closed field unbalanced magnetron sputtering system with various substrate bias duty cycle. The tribological and corrosion behaviors of the multilayer films in Hank's solution were evaluated by a ball-on-disk tribometer and an electrochemical workshop. The duty cycle has a significant effect on the bonding structure, and mechanical and tribological properties of the films. The polarization resistance of the films on Ti alloy is approximately ten times more than that of Ti6Al4V which indicates that higher corrosion resistance can be achieved in Hank's solution at 37 °C. However, the polarization resistance and corrosion current do not change so much with the variation of duty cycle, implying that its influence on corrosion behavior of these a-C/a-C:Ti multilayer films is not so obvious. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nitride (CN x /CN x ) multilayers with sequential sp3-rich and sp2-rich layers were deposited on c-Si substrate by direct current magnetron sputtering. The composition, microstructure and morphology of the films were investigated by the X-ray photoelectron spectroscopy and transmission electron microscopy. In the films, the sp3 C–N rich and the sp2 C–N rich layers exhibit amorphous feature and graphite-like structure, respectively, and the multilayered structure is continuous over relatively well defined and smooth layer interfaces. The mechanical properties of the films were measured by the nanoindentation and nanoscratch tests. The multilayer films showed lower compressive stress and higher hardness than their monolayer components. Meanwhile, the a-CN x multilayer film with a bilayer period of 60nm exhibited the improved mechanical properties, and the lowest friction coefficient and the highest wear resistance. [Copyright &y& Elsevier]