Pole tip recession and staining at the head to tape interface of linear tape recording systems

Abstract

The tribology of the head to tape interface (HTI) of two linear tape recording systems, Travan™ NS20 and OnStream ADR™ are studied from the viewpoint of pole tip recession (PTR) and stain transferred from the tape. Heads tested in humid conditions (60% RH) show the highest PTR increase with deep and wide grooves forming on the pole surface, presumably ploughed by large fragments pulled out from the ceramic in a single catastrophic event. Smaller pullouts are likely to sediment within the recessed poles and increase the PTR acting as three-body abrasive particles. Both the recession of the TiC phase in respect to the Al 2O 3 phase over the Al 2O 3–TiC ceramic used as tape bearing surface (TBS) and the detection of Ti over the pole tip area by Auger electron spectroscopy (AES) identify the pullouts as being TiC fragments. XPS analysis shows a partial oxidation of the TiC phase, however, too superficial to account for the TiC pullout. Stain is detected on the heads either as discrete or restrained deposits (at high humidity) or as a continuous film, forming preferentially over the pole tip surface. The transfer films arises from the recessed pole edge at low humidity (10% RH) and centre at higher humidity (>35% RH), then gradually covers the remaining pole surface within 100 h in both cases. Finally, a preferential transfer is observed over the pole tip area and the TiC phase of the TBS surface, and may relate to their metal-like nature, as opposed to the insulating nature of the other materials.