Friction is an essential part of human experience. We need traction to walk, stand, work, and drive. At the same time, we need energy to overcome the resistance to motion, hence, too much friction costs excess energy to perform work, introducing inefficiencies. In the 21^st century, we are facing the dual challenges of energy shortage and global warming from burning fossil fuels. Therefore, the ability to control friction has become a top priority in our world today. Yet our underst...

In this paper, we first discuss the development of the field of tribology, and highlight some of the main problems encountered in this area, such as lack of systematicness, loose correlation, and inadequate focus on the microscopic perspective. Then, we provide basic formulas of frictional mechanics while considering the friction effect on classical mechanics formulae. In order to carry out the frictional mechanics analysis, we first classify the interface. According to the size analysis of s...

Nowadays it is accepted that the friction force is a combined effect arising from various phenomena: adhesive forces, capillary forces, contact elasticity, topography, surface chemistry, and generation of a third body, etc. Any of them can dominate depending on the experimental force and length scales of the study. Typical forces in macro-tribology are in the Newtons, while are reduced to milli-/micro-Newtons, and nano-Newtons in micro- and nano-tribology, respectively. In this paper, experim...

In this paper we tried to present a qualitative correlation, based on extensive experimental determinations between the value and the evolution of the friction coefficient, wear, and contact temperature, in the case of linear dry contact, for thermoplastic material reinforced with short glass fibers (SGF) and various steel surfaces. The aim was to highlight the evolution of the wear process depending on the evolution of the friction coefficient. As a result, it was possible to graphically ill...

The frictional performance of materials used in face seals is critical to the sealing performance. Silicon carbide is commonly used in hard rings because of its abrasion resistance, corrosion resistance, and thermal shock resistance. In this study, the frictional performance of silicon carbide, including graphite-added silicon carbide, under water and lubrication-absent conditions was studied by using a Falex-1506 tribotester and different working parameters. In addition, the morphology of th...

Platinum (Pt) and nitrogen (N) were co-incorporated in diamond-like carbon (DLC) thin films using a magnetron sputtering system to form PtN-DLC thin films for tribological applications. The Pt content in the PtN-DLC films prepared on Si substrates was controlled by varying RF power applied to a Pt target at a fixed N₂ flow rate. The tribological properties of the PtN-DLC films were investigated with respect to the Pt content in the films. The uncoated Si substrate surface tested ag...

As an example of a very low friction system, Monte Carlo Brownian dynamics simulations have been used to calculate equilibrium structures of a polyelectrolyte brush grafted onto planes. The polymers were calculated in a semi-flexible coarse-grain model that is appropriate to treat the charge density of the polyion. The effect of linear charge density on the polyion ξ, the surface negative charge, and added salts were studied. In salt-free solution, scaling theories predicted the struc...

Friction welding is a solid-state joining process which is applied extensively because of its advantages such as low heat input, efficient application, ease in manufacturing, and environmental friendliness. The present study investigates the mechanical and metallurgical properties of UNS S32205 duplex stainless steel friction- welded joints. The process parameters, namely friction pressure, upsetting pressure, and rotational speed are individually varied from low level to high level (within t...