Ultrathin Liquid Lubrication of Magnetic Head–Rigid Disk Interface for Near-Contact Recording: Part II—Shear Thinning and Thermal Thinning

Abstract

The Carreau shear thinning equation and the modified Roelands thermal thinning equation are combined by using the generalized master curve approach to construct a new thermal non-Newtonian rheology model. The Newton-Raphson method is then used to curve-fit existing experimental data for two perfluoropolyethers to this new model. The thermophysical properties thus found are then used to calculate thermal and shear thinning correction factors for the ultrathin liquid lubrication of magnetic head-rigid disk interfaces. The results of rheology modeling show excellent fits of the widely ranging raw data with the new thermal non-Newtonian model. The results of hydrodynamic analysis indicate that the friction force-isothermal Newtonian shear stress curve for these interfaces is simply a lubricant characteristic curve of thermal-shear thinning.