KINETIC MENISCUS MODEL FOR PREDICTION OF REST STICTION

The time dependence of static friction is an important aspect of tribo logical studies whereby the static friction increases with an increase in the time of stationary contact (rest static friction or rest stict ion). This effect is commonly observed in computer disk drives especia lly at high humidities, in which the static friction increases rapidly with an increase in rest time between some head slider and the disk s urfaces. Fdr the first time a comprehensive kinetic meniscus model is proposed to explain this phenomenon, both for a single asperity and mu ltiple asperity contacts at a liquid mediated interface. It is found t hat the static friction increases up to a certain equilibrium time wit h a power law relationship after which it remains constant. The equili brium time is dependent on the liquid film thickness, tile liquid visc osity and the contact geometry. The model developed is applied to a ro ugh textured disk, a polished disk and a super smooth disk. To study t he effect of the scan size on the meniseus force, the static friction is calculated by using roughness parameters obtained from measurements at different scan sizes.