# Tribology Wiki

Tribo Wiki has the same goal as the well-known Wikipedia: share knowledge from around the globe and create an encyclopedia accessible to anyone. Of course, Tribology Wiki has an emphasis in Tribology! Everyone is invited to read, add, edit and share Wikis.

### Friction Coefficient Tables in Air and Vacuum

09.02.2017

Friction coefficient table of solid lubricants, metals, plastics and anti-friction materials Friction coefficient table for various material pairs in atmosphere and vacuum (see the definition of friction coefficient) is shown below. The data was collected […]

### Coefficient of Friction

06.02.2017

Friction is a force resisting relative motion and may occur at the interface between the bodies, but may also occur within the bodies. The concept of friction coefficient was first formulated by Leonardo da Vinci […]

### Elastohydrodynamic Lubrication (EHL): Theory and Definition

05.02.2017

Definition of Elastohydrodynamic Lubrication (EHL) Elastohydrodynamic Lubrication – or EHL – is a type of hydrodynamic lubrication (HL) in which significant elastic deformation of the surfaces takes place and it considerably alters the shape and […]

### Rolling Contact Fatigue

25.01.2017

Rolling-contact fatigue (RCF) is defined as a failure or material removal driven by crack propagation caused by the near-surface alternating stress field.  It is typically considered that if a bearing is properly mounted, aligned, lubricated, […]

### Generalized Reynolds Equation: Derivation

14.01.2017

Reynolds equation is one of the fundamental equations of lubrication theory and tribology. In the simplest case, it considers incompressible and Newtonian lubricant. This model is sufficient to describe lubricant friction in some cases (relatively […]

### Fatigue Wear

08.01.2017

Fatigue wear is a type of wear where a number of cycles is needed to generate debris. The fatigue process in metals may induce the generation of surface and subsurface cracks, which after a critical […]

### Greenwood and Williamson Contact Model

04.01.2017

Surface roughness was recognized to play a major role in forming friction and transition from one lubrication regime to another [1]. Greenwood pioneered with first rough contact model in 1966 [2]. Inspired by this milestone […]

### Wear Particles

06.12.2016

The wear process results in generation of debris, or particles, of various size, shape, color distributions and chemical composition[1, 2, 3]. These distributions are dependent on normal load, sliding speed, environment and many other parameters[4]. […]

### Corrosive Wear

24.11.2016

Corrosive wear occurs when the component operates in a corrosive media, liquid or gas [1, 2]. In this type of wear, the tribochemical reaction between corrosive agent and the bulk material generates a reaction (protective) […]

### Abrasive Wear

24.11.2016

Abrasive wear occurs when a hard surface or hard particles pass over a soft surface, causing loss of material [1]. However, the abrasive grooves can be found on the wear tracks of the sliding friction […]