CrN and Cr-Al-Si-N coatings were deposited on SUS304 and Si-wafers by a hybrid coating system. The Cr and Al-Si target were connected to the cathode arc ion plating (AIP) and high power impulse magnetron sputtering (HiPIMS), respectively. Various Al and Si contents in the coatings were obtained by changing the power of Al-Si target from 0 to 1 kW. The results demonstrated a face-centered cubic structure in all of the coatings. With increasing Al-Si target power, both the density and mean diameter of the macroparticles on the coating surface declined. As Al and Si contents increased, the microstructure of the Cr-Al-Si-N coatings evolved from a dense column structure, to a finer grain column structure, and then to a compact granular-like structure. The hardness of the coatings increased from 21.5 GPa for the pure CrN coating, to a maximum value of ~27 GPa for the Cr-Al-Si-N coating deposited at 0.4 kW, which was mainly attributed to the solid solution strengthening and increased residual stress. The addition of Al and Si contents led to enhanced wear resistance against alumina balls at both room and elevated temperatures. Meanwhile, the Cr-Al-Si-N coatings also exhibited an excellent resistance to high-temperature oxidation at 800 and 1000 °C, and improved corrosion resistance, as compared with CrN coatings.

In this study, Mo-Cu-V-N composite coatings with high Cu content of ~18 at.% were deposited on 316L stainless steel and YT14 cemented carbide substrates by high power impulse magnetron sputtering in Ar–N₂ gas mixtures. The influence of N₂ partial pressure was investigated with respect to the microstructure and tribological properties of the coatings. The results indicated that the Mo-Cu-V-N composite coatings exhibited FCC B1-MoN phase with a strong (200) preferred orientation, and Cu phase was found to exist as metallic species. As the N₂ partial pressure increased from 0.11 to 0.35 Pa, the peak intensity of (200) plane decreased gradually and simultaneous peak broadening was observed, which was typical for grain refinement. With increasing the N₂ partial pressure, the columnar microstructure became much coarser, which led to the decrease of residual stress and hardness. The Mo-Cu-V-N composite coatings with high Cu content exhibited a relatively low wear rate of 10⁻⁸ mm³/N·m at 25 °C, which was believed to be attributed to the mixed lubricious oxides of MoO₂, CuO and V₂O₅ formed during tribo-oxidation, which cannot be formed in the coatings with low Cu content. When the wear temperature was increased up to 400 °C, the wear rate increased sharply up to 10⁻⁶ mm³/N·m despite the formation of lubricious oxides of MoO₃/CuMoO₄ and V₂O₅. This could be due to the loss of nitrogen and pronounced oxidation at high temperatures, which led the wear mechanism to be transformed from mild oxidation wear to severe oxidation wear.

Binary ZrN and CrN nanostructured coatings deposited by magnetron sputtering were irradiated with 600 keV Kr3+ at room temperature. The ion irradiation fluences varied from 0 to 1×1017 Kr3+/cm-2. The results indicate the microstructure of the CrN illustrates higher stability during the Kr3+ ion irradiation compared to that of the ZrN. The ion irradiation produces surface etching of the CrN coating. However, the etching transfers to recrystallization and grain coarsening on the ZrN coating surface as the Kr3+ fluence increases.

The development of advanced machining techniques requires high-performance tool coatings. To improve the wear resistance and cutting performance of AlTiN coatings, a structure optimization strategy involving bias control and a nano-multilayer architecture strategy is presented. The investigated AlTiN coatings were deposited by cathodic arc evaporation and studied with regard to phase structure, hardness, adhesion, and tribological properties by a combination of X-ray diffraction, nanoindentation, scratch, and ball-on-disk friction tests. A high bias potential (up to −120 V) with enhanced adatom mobility suppressed the formation of the wurtzite structure AlN in AlTiN. In addition, the epitaxial growth of Al_0.67Ti_0.33N on Al_0.5Ti_0.5N in the AlTiN nano-multilayer could also promote the single-phase structure. The hardness of AlTiN-based coatings with a dominated cubic structure was 3–4 GPa higher than conventional ones. In addition, the interlayer interfaces in the Al_0.67Ti_0.33N/Al_0.5Ti_0.5N multilayer could deflect the cracks and thus improve the fracture toughness. As a consequence, the Al_0.67Ti_0.33N/Al_0.5Ti_0.5N multilayer with enhanced mechanical properties obtained the lowest wear rate of 1.1 × 10⁻⁵ mm³/N·m and the longest cutting lifetime of 25 min during dry turning the SUS304 stainless steel.

In this paper, diamond-like carbon (DLC) coatings with Si and O co-doping (Si/O-DLC) were deposited by reactive magnetron sputtering using a gas mixture of C₂H₂, O₂ and Ar to sputter a silicon/graphite splicing target. The O content in the Si/O-DLC coatings was controlled by tuning the O₂ flux in the gas mixture. The composition, chemical bond structure, mechanical properties and tribological behavior of the coatings were investigated by X-ray photoelectron spectroscopy, Fourier infrared spectrometer, Raman spectroscopy, nanoindentation, a scratch tester and a ball-on-disk tribometer. The electrical resistivity of the Si/O-DLC coatings was also studied using the four-point probe method. The results show that the doping O tends to bond with Si to form a silicon–oxygen compound, causing a decrease in the sp³ content as well as the hardness of the coatings. The tribological performance of the coatings can be improved due to the formation of the silicon–oxygen compound, which can effectively reduce the friction coefficient. In addition, the insulating silicon–oxygen compound is doped into the C-C network structure, significantly improving the surface resistivity of the DLC coating with a low sp³ content. The Si/O-DLC coatings with good mechanical properties, tribological performance and electrical insulation properties might be used as protection and insulation layers for microelectronics.

The NbN_x>1 coatings were deposited on Si wafer and SUS 304 stainless steel substrates by a high power impulse magnetron sputtering (HiPIMS) system at various bias voltages and the ratios of nitrogen and argon (N₂/Ar). By virtue of electron probe microanalysis (EPMA), X-ray diffraction pattern (XRD), scanning electron microscope (SEM), atomic force microscope (AFM) and nano indentation test, the relationships between deposition parameters and coatings properties were examined in detail. These coatings show a strong preferred orientation of (200) plane at free bias voltage. With increasing bias voltage, the intensity of (200) plane peak became weaker and the full width at half maximum of peaks ((200) and (111) peaks) became broader, implying the crystalline grain size were decreased. The (200) plane almost is disappeared at −150 V bias voltage and the phase transition maintains the same change tendency with the increase of N₂/Ar gas ratio. The coating microstructure gradually evolved from coarse columnar to dense columnar, and then to compact featureless structure with increase of the bias voltage, corresponding to the decreased surface roughness. The columnar structure of coatings is unrelated to N₂/Ar gas ratio and the thickness is minimum at high N₂/Ar ratio, which is attributed to the poor sputtering capability of nitrogen compared with argon instead of target poisonous effect. The higher hardness (H) and elastic recovery value are obtained for NbN_x>1 (H = 31.3 GPa and W_e = 69.2%) at −150 V bias voltage, suggesting considerable influence of bias voltage on hardness than that of the N₂/Ar gas ratio.