Transient ultra-thin lubricating films in circular point contacts under combined viscous, molecular and surface force actions

There has been a growing trend in component miniaturization in light-weight machines. This has opened new areas of micro-engineering and nano-technology, with diverse applications. The separations in load bearing surfaces in relative motion have become vanishingly small. Lubricated contact characteristics, usually due to elastohydrodynamic lubrication, have given way to films of a few to tens of nanometre thickness. Aside from bulk properties of lubricant, resulting in viscous action, the effects of surface forces and molecular interactions have become significant. These conditions can occur in some high-performance gears and hard disk drive systems. The high storage density required in modem rigid disk drives can be achieved by the use of very smooth surfaces of thin-film rigid disks that allow ultra-low flying of read/write head sliders. The meniscus contribution to the friction can be very large to a point that adhesion may occur. The main aim of this thesis has been to develop a general solution for the problem of isothermal elastohydrodynamic lubrication (EHL) of point contacts under transient conditions and to understand the mechanism of film thickness formation in such narrow conjunctions. [Continues.]