Effect of helium-induced pressure and temperature on lubricant transfer in helium-air-filled hard disk drives

A numerical model combined an air-bearing model with a molecular dynamics model is used to investigate lubricant transfer at the spacing between slider and disk in helium-air-filled drives. The physical properties of the helium-air gas mixtures are calculated with respect to the content of helium. Then, the pressure and temperature distributions induced by helium at the head/disk interface are obtained based on the air-bearing model. Furthermore, the obtained pressure and temperature are used as the inputs of the molecular dynamics model to study the mechanism of lubricant transfer. The results show that the lubricant volume transferred to the air-bearing surface increases with an increase in pressure and temperature. The volume of lubricant transfer decreases slightly as the helium volume in the gas mixture increases from 0% to 80%, after which, the transferred lubricant greatly decreases.