To better understand the influence of carbonization of the Ti interlayer on diamond nucleation and growth, a series of Ti/diamond composite films were deposited on cemented carbide (WC:Co) substrates using a two-step deposition technique. The microstructural properties of the composite films were then characterized by scanning electron microscopy, X-ray diffractometry, and Raman spectroscopy, and their tribological properties were evaluated using a ball-on-disc tester and a metalloscope. The results showed that differences in carbonization for five Ti interlayers of different thicknesses led to variations in the preferred orientations of the TiC layers and in the subsequent nucleation and oriented growth of diamond. This suggests that Ti carbonization significantly influences the nucleation and growth of diamond and subsequently causes variations in the tribological properties of the produced diamond films.

Regarding metal-containing diamond-like carbon (Me-DLC) multilayered films, current research has focused on the influences of macroelements in the transition layer on the mechanical properties. The understanding of influences of microinterfacial structures on the mechanical properties is far from enough. One example is the structure pattern due to carbonation around the layer-to-layer interfaces in the Me-DLC films. In this work, multilayered Cr-DLC films with three modulation periods (Λ) were deposited using midfrequency dual-magnetron sputtering, and the film microstructures and mechanical properties were investigated. Along with changes in Λ, interfacial carbonization induces microstructure changes, and the microstructures include carbon bond, phase compositions, and internal stresses. The microstructure changes affect the mechanical properties, including hardness, elastic modulus, fracture toughness, and adhesion. The results reveal that variation of mechanical properties is involved with the influences of interfacial carbonation on the three factors of the carbon bond (sp2-C and sp3-C bond), phase compositions, and internal stress.

The Ni-based WC alloy coatings were successfully fabricated on NAK80 mold steel by Nd:YAG and CO2 lasers. The microstructure and properties of the laser cladded coatings were analyzed by SEM, EDS, XRD and microhardness tester. The results show that phase constituents of both coatings are mainly composed of tungsten carbide (WC+W2C), Cr23C6, NiCr, CrB2 and γ-Ni. The excellent metallurgical bondings have formed at the interface between the substrate and the laser cladded coatings. Dendrite and white and block WC phase were observed in two kinds of laser cladded coatings, but the dendrite in Nd:YAG laser cladded coating is more fine. The microhardness of NAK80 mold steel is greatly improved by laser cladding, however the microhardness of the CO2 laser cladded coating is even higher than the Nd:YAG laser cladded coating.

The Co-based alloy coatings were successfully fabricated on H13 steel by Nd:YAG and CO2laser. The microstructure and properties of the laser cladded coatings were compared and analyzed by SEM, EDS, XRD and microhardness tester. The results show that the excellent metallurgical bonding has formed at the interface between substrate and laser cladded coatings. Cellular crystal at the bonding zone, cellular dendrite at the central zone and reticular equiaxed crystal near top surface were observed in Nd:YAG laser cladded coating, while the typically hypoeutectic character was found in CO2laser cladded coating. Phase constituents of both coatings are mainly composed of Cr23C6, Co3Mo2Si, MoC, FeCr and γ-Co. The microhardness of H13 steel is greatly improved by laser cladding, however the microhardness of the CO2laser cladded coating is even higher than the Nd:YAG laser cladded coating.

The field emission (FE) of the carbon nanotubes (CNTs) modified by hydrocarbon ion treatment with an energy of 80 eV has been demonstrated. Compared with untreated CNTs, the turn-on field and the threshold field of the modified CNTs decreased significantly. Scanning electron microscopy and transmission electron microscopy indicate that, after hydrocarbon ion treatment, the CNTs are coated by amorphous carbon layer at 300°C of substrate temperature and nanoparticles of graphene stacks at 700°C. It is considered that both amorphous carbon and stacked graphene coating layer can decrease the effective surface work function of CNTs and thus increase FE.