Recent Developments in Wear Prevention, Friction and Lubrication

The knowledge gained from studies on friction, lubrication and wear of contacting surfaces (three terms collectively known as tribology) is met in every branch of engineering. Tribology is a multidisciplinary science involving mechanical engineering, materials and lubrication science, physics, and chemistry. Tribological principles are normally used in characterising the mechanical behaviour of surfaces in relative motion. This involves a very large number of applications ranging in size from the nano-scale (molecular and nano-tribology) to the macro-scale (bearings, tyres, rock drills, etc.). Friction, lubrication and wear are inherent characteristics of the physical world regardless of scale. From the intermolecular forces holding a gecko s feet on a vertical wall to the tractive forces at the contact patches of aircraft tyres; from the lubricating film at the rolling contact of a ball on a rolling-bearing raceway to the soft magma supporting tectonic plates of the earth; from the erosion of human teeth from toothpaste particles to the particle erosion of turbine blades; such diverse phenomena can be described and analysed in tribological terms. Every type of machinery includes parts affected by friction, lubrication, and wear. Therefore, the role of tribology in machine operation and reliability is a major one. As a result, the effect of tribology to modern world economy, even though unknown to the majority of the population, is crucial. Although the effect on the economy has been quantified and found to represent a significant proportion of the gross domestic product of economically advanced countries, the true effect pertaining to the development of technologically advanced products is far greater and not immediately obvious.