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The TiSiN coatings were deposited on Ti 6 Al 4 V alloy by multi-arc ion plating with different substrate negative bias to improve the tribological properties of titanium alloy in seawater. The TiSiN coatings have a coupled structure of amorphous Si 3 N 4 and nanocrystalline TiN. The grain size decreases and the coatings become dense with the increase of the negative bias. The hardness of TiSiN coatings increases from 39 GPa to 47 GPa with the increase of substrate negative bias from 10 V to 40 V. The tribological tests reveal that the TiSiN coatings have a lower friction coefficient and higher wear rate in seawater compared with in atmosphere. Moreover, the wear rates increase with the increase of bias voltage. The TiSiN coating deposited at bias voltage of 10 V shows the best tribological properties in seawater. [ABSTRACT FROM AUTHOR]

Abstract: The CrNx coatings were deposited on 316L stainless steel and silicon (100) wafer by multi-arc ion plating with different N2 flow rates. Composition, microstructures and mechanical properties of the as-deposited CrNx coatings were systematically investigated by X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), nano-indentation and scratch tester. The friction and wear properties of CrNx coatings were investigated by a ball-on-disk tribometer in artificial seawater. The results showed that the coatings transformed from a mixture of Cr+Cr2N to single-phase Cr2N, and then Cr2N+CrN to pure CrN phase with the increase of N2 flow rate. The coatings were all dense except for the one deposited at 200sccm, which clearly exhibited a typical columnar structure. With the increase of N2 flow rate, the friction coefficients first decreased to 0.196 at 100sccm then slightly increased to 0.215 at 200sccm in seawater. However, the depth of wear track and wear rate were lowest at 125sccm, which could be attributed to the denser structure related to better corrosion resistance consisting of Cr2N and CrN phases. [Copyright &y& Elsevier]

In this paper, the patterns of micro-dimples with different area densities and the Cr/GLC films were fabricated by laser surface texturing and magnetron sputtering technology, respectively. The morphologies and surface chemical states of the Cr/GLC films were characterized by AFM, SEM, and XPS. The effects of dimple area density on the tribological behavior of Cr/GLC films under seawater condition were investigated by UMT-3 tribometer in a ball-on-plate reciprocating mode. The experimental results showed that the Cr/GLC film was mainly composed by Cr–C and C–C bonds. Both the friction coefficients and wear rates of the Cr/GLC films in seawater decreased with the increase of dimple area densities in the lower range, whereas, they were constant when the dimple area densities further increased. The Cr/GLC films with proper dimple area density (G3 film) were effective in enhancing the tribological properties because of the entrapment of graphitized particles and seawater in the dimples. The graphitized particles can reduce the strong adhesive interaction between contact surfaces, resulting in the low frictional shear resistance during sliding process. Furthermore, Ca 2 + and Mg 2 + in seawater will be deposited on the counterface in the form of Mg(OH) 2 and CaCO 3 , which with sludge-like matters have some lubricating effects. At the same time, the Cr/GLC films with low dimple area densities exhibited low surface roughness, which could decrease the resistance in sliding process. [ABSTRACT FROM AUTHOR]

CrCN coatings were deposited on single crystal silicon and 316L stainless steel substrates using the cathodic arc ion plating technique with different substrate bias voltages that ranged from − 10 to − 160 V. The relationships between substrate bias voltage and the coating characterization such as nanohardness, modulus, adhesion of the coatings and tribological behavior in ambient air, distilled water and seawater were investigated. Results showed that the hardness and modulus increased significantly with the increase of bias voltages from − 10 to − 160 V. Both the friction coefficients and wear rates of CrCN coatings in ambient air, distilled water and seawater decreased with the increase of bias voltages in the lower range, whereas, they were constant when the bias voltage increased to the high level. In addition, the friction coefficients and wear rates of CrCN coatings under aqueous solution were significantly lower than those under ambient air. Excellent friction and wear behaviors of the CrCN coatings deposited with bias voltages in the range of − 100 to − 130 V may be attributed to low roughness, excellent adhesion strength, high hardness and planar (2D) graphite-like structure. [ABSTRACT FROM AUTHOR]