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This article assesses the potential of using a diamond-like carbon coating doped with tungsten, a-C:H:W (WC/C), on the sliding pairs of refrigeration compressors. The ability of WC/C coating to provide low wear and a low coefficient of friction was experimentally verified in a specific refrigeration compressor operating environment (lubrication with oil diluted with refrigerant) and under extreme operating conditions (starved lubrication with a small amount of oil). Conditions of starved lubrication with a substance of reduced lubricity promote a temperature increase and high mechanical (friction) stresses on the surface of the sliding pairs. These situations can hinder the effective operation of WC/C coatings. Comparative wear tests were carried out for S235JR steel samples with and without WC/C coating. It was found that the samples with the WC/C coating had the lowest wear values and the lowest friction coefficients (approximately 0.06). A low coefficient of friction suggests that even a small amount of oil (one drop) is likely sufficient to achieve mixed lubrication conditions between the tested sliding surfaces and reduce material loss. The tested WC/C coating can protect sliding friction pairs in refrigeration compressors under extreme operating conditions caused by a lack of oil. Less friction reduces the need for energy to drive the refrigeration compressor. Additionally, the significance of this research is highlighted by the fact that the wear tests were conducted using R452A, a novel, eco-friendly refrigerant. [ABSTRACT FROM AUTHOR]

The article presents a study of the tribocorrosion phenomenon and its effects on Inconel 718 alloy produced conventionally by extrusion and additively manufactured using the laser powder bed fusion method. In addition, the samples were subjected to a heat treatment process to change their properties. The research was carried out using the pin-on-disk method in 3.5% NaCl. Based on the study, it was found that the material made with additive technology is more resistant to tribocorrosion phenomenon, and the difference from conventionally made material is about 50%. The synergistic effect between friction and corrosion (ΔZ) occurred. However, heat treatment in the AA-2 variant ensures higher hardness and reduces purely mechanical wear (ZM) and the synergy effect (ΔZ). [ABSTRACT FROM AUTHOR]

Abstract The damage of materials due to both wear and corrosion has a significant impact on engineering systems. Therefore, the industry has recently been more focused on the life cycle costs of the systems and has sought to improve reliability. The reliability and efficiency of machines and equipment depend on tribocomponents operating in a chloride environment. Crucial components are subjected to a wide range of devastating tribocorrosion effects, and in many operations combined with mechanical loadings. A number of protection systems to mitigate corrosion in the marine environment have been employed to counter these problems. One of them are electrodeposited coatings such as Zn and Zn Ni which were documented in numerous research. Much of it has been conducted in areas of corrosion behavior, mechanical properties, and tribology. In order to enhance the corrosion resistance of zinc film, various metals have been implemented. One of them is magnesium. The influence of Mg content in the alloy on the corrosion resistance has been noted by many researchers. However, one cannot find recent scientific publications and papers presenting tribocorrosion performance of Zn-Ni-Mg alloy coatings. Therefore, tribocorrosion behavior of Zn Ni alloy coating with magnesium was investigated. The main aim of this study is to investigate tribocorrosion performance of Zn, and Zn-Ni-Mg alloys coatings with a possibility to replace Zn coating in engineering systems. All coatings were provided on AISI 1045 medium carbon steel with trivalent chrome passivation. The study was carried out in a ball-on-plate combination in 3.5% solution of NaCl. A triple electrode system with a precision four-channel ATLAS 9833 potentiostat was used for monitoring the electrochemical phenomena. The reference electrode was a calomel electrode, SCE. Polarization curves for all samples in 3.5% NaCl were utilized. The evaluation of the surface wear of all samples with coatings was done. The measure of the wear was the depth of the wear trace which was defined on the basis of profilometric measurements. The value of hardness of coatings was identified. Highlights • The Zn-Ni-Mg coating enables the production of a coating with much higher tribocorrosion resistance than the Zn coating. • The tribocorrosion wear difference of the coatings increases with the reduction of the unit pressure in the contact zone. • A larger loss of the material during tribocorrosion tests was found than in the dry friction conditions. • The change of the potential over all tests presents a typical characteristic during tribocorrosion testing. [ABSTRACT FROM AUTHOR]