An investigation into mixed lubrication conditions using electrical contact resistance techniques

Electrical contact resistance (ECR) techniques are widely used to study mixed-elastohydrodynamic lubrication conditions, where direct asperity contact takes place in conditions of very thin lubricant films. This paper presents the use of the ECR technique to study realistic mixed-EHL contacts, identifying the high frequency variation of instantaneous contact resistance on a repeatable basis between two superfinished surfaces. The variation of mean ECR measurements with operating conditions for ground surfaces in contact is investigated, and it is shown that they are strongly related to the lubricant film thickness and lambda ratio. Thermal effects are considered and shown to be highly influential on both the mean and instantaneous contact resistance. The influence of load on contact resistance is also investigated