Nanoparticles based on transition metal dichalcogenides (TMD) are considered to hold great promise as boundary lubricating additive/material for improving friction and wear of engineering functional surfaces. However, TMD nanoparticles cannot provide a comprehensive surface protection against oxidation, corrosion or sludge control. Therefore, the current lubricant developments may still have to depend on conventional additives such as zinc dialkyl dithiophosphate (ZDDP), and it is essential to understand the interaction of nanoparticles with such additives in order to explore how these nanoparticles could be commercially employed in fully formulated lubricants. This paper examines the tribological properties of three different nanoparticles: inorganic fullerene-like MoS 2 , rhenium-doped MoS 2 and MoS 2 nanotubes in steel and steel with preformed ZDDP tribofilm surfaces using a pin-on-disc-type tribometer under reciprocating sliding conditions. The resulting tribofilms have been evaluated using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, transmission electron microscopy and atomic force microscopy. The results show that although the nanoparticles are able to reduce friction in all cases, the resulting tribofilm composition and morphology, and their lubricating mechanisms are significantly different. The MoS 2 nanoparticles and nanotubes show good synergism with ZDDP, and tribofilms formed from nanoparticles exhibit improved friction and wear properties compared to that typically formed from ZDDP.

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The use of different process media such as cutting fluids, coolants, honing oil and washing media in typical machining operations exceeds 5,000 m3 per year. These media support critical functions such as lubrication, corrosion protection, cleaning and cooling, and have an enormous effect on the manufacturing performance. The tribological properties of these media are improved by using additive molecules, which are physically or chemically adsorbed on the surface of tools and workpieces. The additive performance is especially important in water lubricated tribosystems, where the environment is highly corrosive. The role of corrosion inhibitors typically applied is to neutralize the pH of contaminants in the fluid. Ethanolamines and ethylamines are known as ligands which can form chelate bonds with metals via their amino, hydroxyl and deprotonated hydroxyl-groups. In tribology they are widely spread, as corrosion inhibitors and detergents especially for water based lubricants. This study inquires the tribological performance of amine-based solutions in two types of tribotesters which apply different contact conditions. The dissimilar behaviour under rolling and sliding contact is explained in terms of the structure of the adsorbed compounds. Understanding the performance of the first chemisorbed layers of additives on the workpiece provides essential information for optimizing lubrication in aqueous solutions.

The feasibility and benefits of focused ion beam–scanning electron microscopy (FIB-SEM) tomography for the characterization of non-metallic inclusions in bearing steels was evaluated. The technique enables precision, essentially stress-free, serial milling of microstructural features, from which a three-dimensional (3D) profile can be reconstructed. 3D imaging of the inclusions using FIB-SEM has provided relevant information about the inclusion connectivity (bonding/debonding between the inclusion and the steel matrix), the real shape and size of the inclusions, and the spatial distribution information of the inclusion. Additionally, the analysis has provided some insights on their inner structure (presence of cracks, etc.).