Micro/nanomechanical and tribological studies of bulk and thin-film materials used in magnetic recording heads

Abstract

Micro/nanomechanical characterization of the bulk Al 2O 3–TiC and Ni–Zn ferrite, and thin films of Co–Zr–Ta and Al 2O 3 used in magnetic recording heads have been carried out. Hardness, elastic modulus and scratch resistance of these materials were measured by nanoindentation and microscratching using a nanoindenter. Fracture toughness was measured by indentation using cube corner and Vickers indenters. Friction and wear properties for these materials were measured using an accelerated ball-on-flat tribometer. Al 2O 3–TiC shows the highest hardness, elastic modulus and scratch resistance as well as the lowest wear damage, followed by the Ni–Zn ferrite, Al 2O 3 films, and Co–Zr–Ta film. The Co–Zr–Ta film exhibits the highest fracture toughness, followed by the Al 2O 3–TiC, Al 2O 3 films and Ni–Zn ferrite. There exists a good correlation between mechanical properties and wear damage. Higher mechanical properties result in less wear damage. In general, the bulk Al 2O 3–TiC and Ni–Zn ferrite show lower damage than the Co–Zr–Ta and Al 2O 3 films. For the thin films studied, the Al 2O 3 films show higher mechanical properties and less scratch and wear damage.