Water lubrication assisted by small-quantity silicone oil

Abstract

In this paper it was demonstrated that a small quantity of silicone oil could be employed as a secondary lubricant to assist water lubrication when there appear short-time sever working conditions. With a deliberately fabricated fiber-guide nozzle a short-time injection of silicone oil to water lubricated block-on-ring contact in the mixed lubrication could reduce friction of the contact markedly. With increase of the ring speed the friction reduction ratio decreases first and then slightly increase thereafter. Measurements of the wear track displayed more wear reduction under higher ring speeds and larger viscosity. It was proposed that the friction and wear reduction could be attributed to the water-excluded lubrication film formation in the whole contact zone by silicone oil, which was validated by optical interferometry measurement of the lubrication films. In addition, through fluorescence technique it was found that water environment can reduce the wettability of the silicone oil on the lubrication track so that the oil replenishment on the track is enhanced and the film thickness increases.