Mechanical properties and wear characteristics of various thin films for rigid magnetic disks

The relationships between mechanical properties and wear characteristics are described for carbon, SiO₂ and CoNi-on-Cr thin films. The films are prepared on various rigid substrates in the submicron thickness range by RF magnetron sputtering. Mechanical properties examined include microhardness, Young´s modulus and internal stress. Wear resistances are evaluated for thin films sliding against a thin film head Al₂O₃-TiC slider. There is no correlation between the microhardness and the wear resistance. However, the load-indentation depth curves provide useful information, since the curve profile varies reflecting the presence of microdefects closely related to wear characteristics. A clear and common relationship holds between Young´s modulus and wear resistance which is a maximum at 0.8-0.9 times the modulus. The wear resistance of CoNi films decreases as the tensile stress increases in the Cr substrates. The properties of carbon films depend on their own internal stress; an increase in compression stress leads to deterioration in their wear resistance