Characterization of the head-disk interface at nanometer dimensions

Characterization of the head and disk surfaces at nanometer dimensions is crucial for optimizing the tribological performance of the head-disk interface as discussed in the following examples given in this paper. Friction mapping at a nano-scale is used to study the nucleation sites of smears on a disk from a failed drive showing high nonrecoverable error rate at the OD. Nanoindentation data suggest that the hardness of the alumina grains is comparable to that of the TiC grains. Al₂O₃-TiC substrates from vendor B exhibit the lowest hardness of 30 GPa. During the CSS test, sliders with vendor B Al₂O₃-TiC substrates exhibit relatively greater amount of wear debris and grain pullouts as compared to those of the vendors A and C. The nature of the damage to the DLC coating during nanoscratching can be qualitatively correlated to hardness, toughness, high residual stresses, and weak adhesion due to an impurity at the coating-substrate interface. The correlation between the highest nanowear resistance and best CSS wear performance of DLC coatings indicates that the wear properties at a nanoscale can be used as an indirect measure of the CSS performance of the carbon overcoats