Characteristics of the Structure,Mechanical, and Tribological Properties of a Mo-Mo2N Nanocomposite Coating Deposited on the Ti6Al4V Alloy by Magnetron Sputtering |
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Authors: | Stanisł aw Adamiak,Wojciech Bochnowski,Andrzej Dziedzic,Ł ukasz Szyller,Dominik Adamiak |
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Affiliation: | 1.College of Natural Sciences, University of Rzeszow, Pigonia 1, 35-310 Rzeszow, Poland;2.PlasmaVac, Unit 6 Barnack Ind Estate, Salisbury SP2 0AW, UK;3.Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, ON M5S 3G8, Canada; |
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Abstract: | Mo-Mo2N nanocomposite coating was produced by reactive magnetron sputtering of a molybdenum target, in the atmosphere, of Ar and N2 gases. Coating was deposited on Ti6Al4V titanium alloy. Presented are the results of analysis of the XRD crystal structure, microscopic SEM, TEM and AFM analysis, measurements of hardness, Young’s modulus, and adhesion. Coating consisted of α-Mo phase, constituting the matrix, and γ-Mo2N reinforcing phase, which had columnar structure. The size of crystallite phases averaged 20.4 nm for the Mo phase and 14.1 nm for the Mo2N phase. Increasing nitrogen flow rate leads to the fragmentation of the columnar grains and increased hardness from 22.3 GPa to 27.5 GPa. The resulting coating has a low Young’s modulus of 230 GPa to 240 GPa. Measurements of hardness and Young’s modulus were carried out using the nanoindentation method. Friction coefficient and tribological wear of the coatings were determined with a tribometer, using the multi-cycle oscillation method. Among tested coatings, the lowest friction coefficient was 0.3 and wear coefficient was 10 × 10−16 m3/N∙m. In addition, this coating has an average surface roughness of RMS < 2.4 nm, determined using AFM tests, as well as a good adhesion to the substrate. The dominant wear mechanism of the Mo-Mo2N coatings was abrasive wear and wear by oxidation. The Mo-Mo2N coating produced in this work is a prospective material for the elements of machines and devices operating in dry friction conditions. |
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Keywords: | Mo-Mo2N coatings nano-structure mechanical properties tribological wear magnetron sputter |
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