Numerical contact analyses of layered rough surfaces for magnetic head slider-disk contact

摘要

A three-dimensional numerical model is developed to investigate the contact behavior of layered elastic-plastic rough surfaces and is applied to the asperity contact and stiction at the magnetic head slider-disk interface. The model yields insight into the effect of a diamondlike carbon overcoat on the contact performance of thin-film disks. Three-dimensional layered elastic-plastic rough surfaces resembling magnetic thin-film disks are generated in the computer with specified surface roughness parameters, σ and β*; diamondlike carbon overcoat thickness; Young's modulus and the hardness ratio of the over-coat to the substrate. A liquid film of known mean thickness is introduced over the deformed rough surfaces. Contact statistics such as the fractional contact area, maximum pressure, surface and subsurface stresses, and relative meniscus force are predicted under a designated normal load. Two threshold values of layer thickness are defined as the ceiling-floor critical thickness, above or under which the layer-substrate effect becomes dominant and the substrate-layer effect is negligible. Layers with a high Young's modulus and hardness are beneficial in reducing adhesive friction, stiction, and abrasive wear. However; high surface and subsurface stresses would accelerate the cracking and delaminating failure and requires a trade-off. Optimum layer parameters are identified to provide low friction, stiction and wear.