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Thick diamond‐like carbon (DLC) coatings with different silicon (Si) transition layer thickness are deposited by hollow cathode plasma immersion coating technology. The results show that the internal stress of the coating can be tuned by changing the deposition time of Si transition layer, thereby obtaining good adhesion strength. Friction and wear results show that all coatings have good tribological properties. The coating with 8 min Si transition layer (Si‐8) demonstrates the lowest friction coefficient (μ ≈ 0.03), even achieves ultralow friction (μ ≈ 0.008) for a short time. However, the wear rate of Si‐8 coating is found to be the largest (2.1 × 10−16 m3 (N m)−1. The low friction coefficient of Si‐8 coating is related to its high degree of graphitization, complete transfer film and fine wear debris. In contrast, the Si‐16 coating has the lowest wear rate of about 5.6 × 10−17 m3 (N m)−1 with a relatively high friction coefficient (μ ≈ 0.1). This is due to its high hardness and the formation of a nano‐twisted double helix carbon debris during the friction process. This nano‐twisted double helix structure can consume additional plastic deformation energy, while reducing the interface contact area and increasing the interface bearing capacity, thereby improving the wear resistance of the thick DLC coating. [ABSTRACT FROM AUTHOR]

The Mo x N coatings are deposited by direct current magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HiPIMS). It is found that the Mo x N coatings prepared by HiPIMS has a denser microstructure, higher hardness and wear resistance. Besides, the effect of peak current is investigated with respect to the microstructure, mechanical properties and tribological behavior of the coatings. As the peak current increases, the cross-sectional morphology of the coating transforms from featureless to columnar morphology, and the preferred orientation of the coating gradually transfers from (111) to (200). However, the hardness of the coating is not significantly influenced by the peak current. The Mo x N coating with a peak current of 260 A owns a low friction coefficient of 0.28, which is better than that of the Mo x N coating prepared by DCMS. The Mo x N coating with a peak current of 300 A provides excellent wear resistance with the lowest wear rate of 5 × 10−8 mm3/(Nm). [ABSTRACT FROM AUTHOR]

Adhesive wear is one of the major reasons for the failure of components during various tribological application, especially for rubbing with viscous materials. This study presents CrN/DLC/Cr-DLC multilayer composite coatings prepared on a plasma enhanced chemical vapor deposition (PECVD) device with the close field unbalanced magnetron sputtering ion plating (CFUBMSIP) technique. SEM, XRD and Raman spectroscopy were used to determine the structure of multilayer coatings. It was found that the multilayer coatings are composed by the alternating CrN and DLC layers. Compared with the single CrN coatings, the friction coefficient of the CrN/DLC/Cr-DLC multilayer coating decreases about more than seven times after sliding a distance of 500 m. This helps to reduce the adhesive wear of multilayer coatings. Compared with the single CrN and DLC coating, the wear rate of the CrN/DLC/Cr-DLC multilayer coating is reduced by an order of magnitude to 7.10 × 10 −17 (sliding with AISI 440C) and 2.64 × 10 −17 (sliding with TC4) m 3 /(N m). The improved tribological performance of multilayer coatings mainly attributes to the introduction of lubricant DLC and hard support CrN layers, the enhancement of crack propagation inhibition, and the increment of elastic recovery value W e (71.49%) by multilayer design method. [ABSTRACT FROM AUTHOR]

To improve the adaptability of GLC coatings in aqueous environment, a dense structure for GLC coatings was designed and constructed by nitrogen doping via PVD technique. The nitrogen content was tailored via tuning the nitrogen flow rate to optimize the tribological performances of the N-doped GLC coatings in water as well as to investigate the effects of different nitrogen contents. And the optimal nitrogen flow rate was 5 sccm. The results implied the nitrogen doping favored the increase of adhesion strength. The dense structure built by nitrogen doping entitled the N-GLC coatings to improved wear resistance in water and enhanced aqueous-adaptability, because the corrosion by water can be effectively inhibited compared with the column-structured nitrogen-free GLC coatings via PVD. [Display omitted] • The nitrogen modified GLC coatings with dense structure and better adhesion strength were constructed via PVD technique. • The nitrogen contents in the N-doped GLC coatings can be tailored by tuning the nitrogen flow rate in the PVD process. • The nitrogen-free GLC coating was failed in water environment, while the N-GLC coating with 5 sccm flow rate showed a lowest wear rate of 2.47 × 10-8 mm3/Nm. • The nitrogen doping contributed to the densification of the coatings and thus improved their aqueous-adaptability. [ABSTRACT FROM AUTHOR]

Fe-based amorphous alloys (FAA) have excellent anti-corrosion and anti-abrasive comprehensive performances. However, sprayed thin FAA coatings with high porosity cannot provide efficient protection, or even accelerate the corrosion rate of the substrate due to galvanic corrosion. Laser re-melting densifying is usually used to improve the anti-corrosion performance of sprayed coatings. There are two disadvantages of the common laser re-melting method, including crystallization and residual stress. In the present paper, a low density energy laser re-melting method was used to improve the performance of cold spraying (CS) FeCoCrMoBCY FAA coating on 40Cr substrate. The results show that the CS FAA coatings were crystallized partially during the melting process. The hardness of the coating is improved at the melting zone after laser re-melting, which improves the anti-abrasive performance. Potentiodynamic test results show that laser re-melting can decrease the corrosion rate, but the salt spray test indicates that low energy density re-melting cannot eliminate penetrated diffusion passage. Further optimization should be conducted to improve the anticorrosion performance for this method. [ABSTRACT FROM AUTHOR]

The preparation and investigation of lead-free bronze solid-lubricating coating is of great significance for the protection of moving parts in seawater condition. In this work, the (Cu-5Sn)/Al 2 O 3 -Ag solid-lubricating coating was prepared by low-pressure cold spray (LPCS) technology. The influence of the Ag content (0–20 wt%) in feedstocks on the microstructure, deposition efficiency and mechanical properties of the coatings was investigated. Meanwhile, the tribological behavior of the coatings in artificial seawater environment was examined. The results showed that the Al 2 O 3 particles contribute to the densified microstructure and the increased Ag content in powders improved the deposition efficiency of the coatings, but inferior hardness. The satisfactory bonding strength between the coating and substrate was achieved. In artificial seawater condition, the friction coefficient of the coatings decreased with the increase of the Ag content in the coatings. However, more Ag will sacrifice the anti-wear property of the coatings. The wear mechanisms of the coatings were abrasive and corrosive wear. • The (Cu-5Sn)/Al 2 O 3 -Ag solid-lubricating coating was deposited by low-pressure cold spraying. • With the increase of Ag content in feedstock, the deposition efficiency of the coating increased. • The coating possesses a satisfactory bonding strength with the AA 7075-T651 substrate. • The coating has the low friction coefficient and high wear resistance in seawater condition. [ABSTRACT FROM AUTHOR]

[Display omitted] • The (CrAlTiNbV)N x high-entropy coatings are prepared by magnetron sputtering method. • All coatings exhibit columnar growth morphology and own a single FCC structure. • The S-38 owns a friction coefficient of 0.096 and wear rate of 1.8 × 10−7 mm3/(N·m). • The excellent wear resistance of S-38 is mainly attributed to its dense structure. (CrAlTiNbV)N x high-entropy nitride coatings are deposited via tuning nitrogen flow rates, and evaluating their influence on the microstructure, mechanical and tribological properties of the coatings. All deposited coatings exhibit columnar growth morphology and own a single face-center-cubic structure. As the nitrogen flow rate increases, the preferred orientation of the coating gradually transfers from (1 1 1) to (2 0 0) and (2 2 0), and then changes back to (1 1 1) with the nitrogen flow rate continues to increase. The S-38 sample possesses the optimal plastic deformation resistance and adhesion strength. Friction and wear results show that the (CrAlTiNbV)N x coating deposited at nitrogen flow rate of 38 sccm owns the best tribological properties with a friction coefficient of 0.096 and wear rate of 1.8 × 10−7 mm3/(N·m) in 4050# aviation oil. [ABSTRACT FROM AUTHOR]