Despite continuous improvements in machine elements over the past few decades, lubrication issues have impeded human exploration of the universe because single solid or liquid lubrication systems have been unable to satisfy the ever-increasing performance requirements of space tribology. In this study, we present an overview of the development of carbon-based films as protective coatings, with reference to their high hardness, low friction, and chemical inertness, and with a particular focus ...

Using an MFT-R4000 tester at room temperature, the leaf-surface wax of two desert plants, Ammopiptanthus mongolicus (AM) and Reaumuria soongorica (RS), was extracted and evaluated for its potential as a lubricant additive in polyalphaolefin (PAO) for steel–steel contact. Gas chromatography–mass spectrometry analysis was performed to identify the composition of the AM leaf-surface wax, and scanning electron microscopy and X-ray photoelectron spectroscopy were used to investigate ...

The suitable brake torque at the shoe–drum interface is the prerequisite of the active safety control. Estimation of accurate brake torque under varying conditions is predominantly the function of friction coefficient at the shoe–drum interface. The extracted friction coefficient has been used in the antilock braking system (ABS) algorithm to plot the μ–slip curve. The longitudinal forces like Coulomb friction force, contact force and actuating forces at the shoe ends are resolved unde...

In this study, we evaluated the wear properties of four brands of brake pad available in the Nigerian market. In particular, we assessed the tribo performance and service life of the brake pads. We purchased four commercial brands of brake pads used in light duty cars and coded them as AU, SN, TY and SM, respectively. A small piece of the brake pad lining materials was carefully chiseled from the back plates to obtain samples for the experiments. We conducted Brinell hardness tests using a te...

In this study, the effects of deep cryogenic treatment (DCT) on the mechanical and tribological properties of AISI D3 tool steel were investigated together with a systematic correlation between their hardness and wear resistance. It was found that conventionally heat treated AISI D3 tool steel samples were significantly hardened via an additional DCT, which was attributed to the more retained austenite elimination, more homogenized carbide distribution and more reduction in carbide size in th...

This paper reports a series of studies on the lubricant properties, elastohydrodynamic film thickness, and coefficients of friction of several commercially available ester base stocks, i.e., diisooctyl phthalate (DIOP), diisodecyl phthalate (DIDP), diisotridecyl phthalate (DITDP), diisooctyl sebacate (DOS), diisotridecyl sebacate (DTDS), trihydroxymethylpropyl trioleate (TMPTO), and pentaerythritol tetraoleate (PETO). The results include densities and viscosities from 303 to 398 K, and elasto...

Tribocorrosion is a degradation mechanism resulting from the interaction of mechanical (wear) and chemical (corrosion) phenomena. This interaction leads to surface damage that does not correspond to the simple sum of wear and corrosion taken separately. Testing tribocorrosion of material pairings thus requires the capability not only to control the mechanical and chemical test parameters but also to identify the relative contribution of corrosion and wear in the overall material degradation. ...