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Transition metal dichalcogenides are well known for their outstanding lubricating property. The special one of the family members, metallic NbSe 2 film, was deposited by sputtering in this study. The microstructure, electrical conductivity and tribological properties of NbSe 2 films were investigated by energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), grazing incidence X-ray diffraction (GIXRD), high resolution transmission electron microscopy (HRTEM), four-probe meter and ball-on-disk tribometer. The results showed that the microstructure of NbSe 2 film could be tailored by simply controlling the sputtering power. The suitable power of 180 W promoted to crystal growth of NbSe 2 film with edge plane orientation and formation of columnar structure, which possessed low static contact electrical resistivity and good adhesive strength on steel substrate. Both the dense and loose films made by lower and higher power, respectively, exhibited the downtrend of contact electroconductive and lubricative properties. The mechanism was discussed in terms of densification and crystallinity of films and transfer film formed on counterpart surface after sliding friction process. This novel NbSe 2 film with low friction and dynamic contact electrical resistance behaviors was expected to a more feasible candidate for lubricative and electroconductive bifunctional material application. [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]

[Display omitted] • The nanostructure of a-Si:H interlayer can be tailored by bias power. • Nanoporous interlayer transforms into clusters and then network with increasing bias. • The crosslinked network results in the highest adhesion and the lowest stress. • The tiny clusters weaken the lattice mismatch and reduce the Si-Fe bonds. Different nanostructures of the a-Si:H interlayer were designed by tuning the bias power to reveal the impacts on the adhesion of thick DLC coatings prepared by PECVD. Besides the formation of stable Si-Fe bonds, the a-Si:H interlayer transformed from nano-porous structure into tiny clusters and finally into crosslinked network by raising the bias power from 125 to 425 W. The interlayer with crosslinked network promoted the formation of more Fe-Si dangling bonds at the bonding layer as well as better structure matching with top layers, resulting in the highest adhesion strength of 32 N and the lowest internal compressive stress of −1.44 GPa. When amounts of tiny clusters were formed in the interlayer at 275 W, the lowest adhesion strength of 23.5 N was obtained. This was due to the low chemical reactivity of tiny clusters hindered the formation of the Si-Fe bonds. [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]