Particle induced damage on heads and discs due to fine particles of different materials

Fine particles of aluminum, stainless steel, silicon, slider ceramic (Al₂O₃-TiC) and sputtered alumina were introduced at the head/disc interface of hard disc drives. Experiments were conducted with discs made from aluminum and glass substrates. Glass substrates were much harder than aluminum substrates. It was found that the type of damage introduced on the disc and slider was to some extent unique for each material, and also closely related to the relative hardness of the interacting materials. The introduced particles could be deformed, embedded, disintegrated or sheared. Typical damages on disc caused by particle interaction varied from light deformation to very deep circumferential scratches. From AFM, SEM/EDX and materials hardness/elastic modulus data, we proposed mechanisms by which particles of different materials could cause damages on the two types of discs