Sliding wear tests of a titanium-matrix composite (TMC) against M35 steel were performed at room temperature. To improve the wear performance of the TMC, an attempt was made to induce a protective tribofilm by artificially supplying nanoscale materials, viz. multilayer graphene (MLG), Fe2O3, and their composite and mixture, onto the sliding tracks. Irrespective of the load, MLG or Fe2O3 additives could

Synthetic MSH can solve the shortcomings of natural, self-repairing serpentine materials, but its tribological properties are not ideal. Herein, Ni was selected as an accelerant to prepare MSH/Ni composite powder to obtain better friction performance. The tribological performance of MSH/Ni was investigated using ball-disk wear tests, and the worn surfaces were characterized by SEM, EDS, WLI, and XPS

The objective of this study was to evaluate the influence of adhesive layer thickness on wear damage of the bonded interface between enamel and composite inlays using self-adhesive resin cement. Sixty bonded interface samples consisting of four different adhesive layer thicknesses (10 ± 10, 50 ± 10, 100 ± 10 and 150 ± 10 μm) were prepared from resin composite (Tetric N Ceram Bulk Fill; Ivoclar Vivadent

We investigate the underlying tribological mechanisms and running-in process of a semi-crystalline polymer using molecular-dynamics simulations. We subject a slab of simulated polyvinyl alcohol to a sliding contact asperity resembling a friction force microscope tip. We study the viscoelastic response of the polymer to the sliding and show both plastic and elastic contributions to the deformation,

Graphene is a good candidate for solid lubricants due to its unique atomic structure. Its lubrication properties are sensitive to chemical modifications such as hydrogenations. Here, an investigation on the lubrication behavior of hydrogenated graphene on a substrate of diamond-like carbon films is performed via molecular dynamics simulations. Hydrogenated graphene exhibits excellent lubrication behaviors

Recently, Dalvi and co-authors have shown detailed experimental data of adhesion of soft spheres with rough substrates with roughness measured down to almost the atomic scale, finding that the Persson and Tosatti theory gave satisfactory predictions of the apparent work of adhesion during loading, once the increase of the surface area due to roughness is correctly computed at extremely small scales

The thermo-oxidative degradation of a multiply-alkylated cyclopentane (MAC) lubricant for space applications is investigated. Accelerated aging tests at temperature levels between 60 °C and 150 °C are performed and the aging behavior is investigated in detail with spectroscopic, mass spectrometric and chromatographic techniques as well as tribological testing on a ball-on-disk setup. The degree of

I consider fluid flow at the interface between solids with random roughness. For anisotropic roughness, obtained by stretching isotropic roughness in the x-direction by a factor of \(\gamma ^{1/2}\) and in the y-direction with a factor of \(\gamma ^{-1/2}\), I give an argument for why the flow conductivity in the critical junction theory should be proportional to \(\gamma \) in the x-direction and

We study the nominal (ensemble averaged) contact pressure p(x) acting on a cylinder squeezed in contact with an elastic half space with random surface roughness. The contact pressure is Hertzian-like for \(\alpha < 0.01\) and Gaussian-like for \(\alpha > 10\), where the dimensionless parameter \(\alpha = h_{\rm rms}/\delta \) is the ratio between the root-mean-square roughness amplitude and the penetration

This paper examines the effect of dispersant and anti-wear additives on fretting wear in lubricated bearing steel contacts. Reciprocating sliding ball-on-flat fretting tests with a stroke length of 50 μm have been carried out on steel-to-steel contacts in both dry and lubricated conditions. Wear and friction coefficient have been measured, and surface characterisation has been carried out using optical

In some industrial situations, components are subject to repetitive impact in the presence of a slurry. A novel repetitive impact-with-slurry test rig was developed to evaluate the behaviour of a wide range of engineering materials in such conditions. The test materials could be categorised into five main groups – heat treated steels, stainless steels, chromium cast irons, hardfacing coatings and superalloys

Ionic liquids (ILs) are potential lubricant additives that can potentially perform simultaneously as friction modifiers and anti-wear agents. In addition, they possess good thermal stability, they are non-flammable, they have high polarity with negligible volatility, etc. These characteristics make them also ideal for polar lubricants, like water-based fluids. In this work, the friction and wear mechanisms

The contact between rough metallic bodies almost always involves plastic flow in the area of real contact. We performed indentation experiments on sandblasted aluminum surfaces to explore the plastic deformation of asperities and modeled the contact mechanics using the boundary element method, combined with a simple numerical procedure to take into account the plastic flow. The theory can quantitatively

Metallic seals are crucial machine elements in many important applications, e.g., in ultrahigh vacuum systems. Due to the high elastic modulus of metals, and the surface roughness which exists on all solid surfaces, if no plastic deformation would occur one expects in most cases large fluid flow channels between the contacting metallic bodies, and large fluid leakage. However, in most applications

Graphite is a well-known solid lubricant (SL) additive widely used both as a standalone SL and also as additive in lubricating oils, greases, composites, etc. Size of the additive particles especially nano-particles (NPs) is a major attribute to the performance properties of a composite, oil, grease, etc. This paper highlights the influence of graphite particles of four sizes viz. 50 nm, 450 nm, 4 microns

The macroscale friction and wear properties of the Zr44Cu10Ni10Ti11Be25 metallic glass were investigated as a function of environmental oxygen concentration and contact force. We found remarkably low and predictable friction when both oxidation and frictional heating (that can lead to thermomechanically-driven crystallization) were supressed. Conversely, oxidation and the formation of a mixed metal-oxide

The electric-carrying nanofriction properties of graphene are vitally important in the reliability and lifetime of graphene-based micro-/nanoelectromechanical systems. However, ubiquitous atomic-scale steps on graphene have an impact on their friction properties. In this work, electric-carrying nanofriction properties of atomic-scale steps on graphene were studied using the conductive atomic force

In this work, airborne brake wear particulate matter (PM) emissions from a brake system were investigated by time-resolved and temperature-dependent measurement using a dynamometer. The measurement was performed for representative friction materials, 3 low-steel (LS) and 4 non-steel (NS), which are currently in worldwide use. The PM emission factor was found to be varied as large as by one order of

The aim of the work is to show both the similarities and differences in the formation of deformation-induced roughness in contact compression in the presence of oil and the problem of free surface roughing during uniaxial stretching in a plastic area. The relationships between changes in the roughness are caused by the deformation of the sample and the viscosity of oil at the contact area. It has been

Three ecofriendly protic ionic liquids (PILs), 2-hydroxyethylammonium 2-ethylhexanoate, 2-hydroxymethylammonium 2-ethylhexanoate, and 2-hydroxydimethylammonium 2-ethylhexanoate, with different extents of hydrogen bonding and ionicities, were synthesized and examined as neat lubricants and lubricant additives to a mineral oil (MO) under steel/steel and steel/aluminum contacts. The stability of each

Soft contact lenses are medical devices made from aqueous polymeric gels that are worn on the eye to correct refractive errors. These devices interrupt the natural contact pairing between the cornea and the eyelid and create two interfaces comprised of a synthetic material and the epithelia—contact lens surfaces versus (1) the cornea and (2) the eyelid conjunctiva. The cellular responses to friction

MoS2:glycol hybrid nanoparticles were synthetized through a polyol route. Their tribological properties when used as lubricant additives in a PAO 6 base oil were investigated using a pin-on-disk tribometer. An important friction reduction and good anti-wear performances were observed compared to the base oil and to the no modified particles. The MoS2:glycol nanoparticles were characterized by thermogravimetric

Oleylamine (hereinafter referred to as OM)-modified CeO2 nanoparticles were synthesized by a one-pot pyrolysis method. The tribological properties of the as-prepared CeO2 nanoparticles as the lubricant additive in poly-alpha olefin (PAO) were investigated with a four-ball machine, and their lubricating mechanism was discussed in relation to worn surface analyses by SEM, EDS, and XPS. Findings indicate

Friction of textiles on the human forearm is an important factor in comfort sensations of garments. We built an experiment to measure friction for textiles sliding on the forearm under loading conditions which are characteristic for wearing shirts or jackets. The hair coverage of the participants’ forearm was quantified by image analysis of photographs of the arm in the region of contact. Friction

This work investigates in situ friction-generated copper nanoparticles at the sliding in the precursor solution of copper formate tetrahydrate and octylamine, which induced by frictional heat, it can effectively mitigate wear while slightly reducing friction coefficient. The frictional heat between tribo-pairs accelerated the decomposition of the precursor into in situ generated copper nanoparticles

The original publication contained an incorrect mention of the time duration for Fig. 12 in Appendix. The expanded friction curve is for the initial 30 s of sliding.

Titanium alloys are used for their good mechanical and corrosion properties, but generally experience poor wear behavior. This can effectively be counteracted by a thermal oxidation treatment, reducing wear significantly. Employing a special sample preparation, we study the transition of tribological properties between thermally oxidized and bulk Ti6Al4V on a single sample. While oxygen signal intensity