Disk burnishing for head-wear reduction studied by pin-on-disk tests

In recent hard disk drives, head-disk contacts are becoming unavoidable with the decrease in head-disk spacing to less than 10-nm levels. Head-wear reduction is one of the main subjects to be studied for further reducing of the spacing. For this purpose, we started the study of the disk burnishing technique on pin wear using transparent pin-on-disk seek wear tests, in addition to the effects of carbon overcoat films, lubricants, and disk roughness. Conventionally, there have been two disk burnishing techniques, head burnishing (HB) and tape burnishing (TB). We proposed another new burnishing technique, contact burnishing (CB). In CB, a hard spherical pin is pressed onto a disk surface and it burnishes disk asperities. Considering HB would not be effective for disk surface machining, we also studied TB. In this paper, we first describe the importance of disk burnishing with our extended wear equation. The CB technique and its effects will be explained next, and the effects of TB conditions on pin wear are then illustrated.