Under fluid film lubrication, the particulate contaminants in the fluid cause three-body abrasive wear on critical surfaces. The wear not only depends on the hardness of the wearing surface (Hj), but also on the hardnesses of its opposing surface (Hb) and the involved abrasives (Ha). In this paper, the hardness effect, particularly the relationships among these three hardnesses, is studied, by exploring the interdependence between two hardness ratios: the ratio between two rubbing surfaces (Hb/Hj) and the ratio between the surface to be protected (usually the harder surface) and the abrasives (Hj/Ha). Three types of journal-bearing pairs (Hb/Hj = 0.75, 0.6, and 0.3) were tested, subjected to four abrasive particles (Hj/Ha ranges from 0.14 to 2.75). The wear linearly varies with the Hj/Ha value at each metal hardness ratio on log-log diagram. The empirical constants in the wear function are obtained. The critical hardness ratio and the wear coefficient are also analyzed.

Laser-texturing at the landing-zone of a magnetic disk surface provides a head-bump-interface with well-defined contact geometry, which can be optimized for better drive tribology performance. This paper presents the investigation aimed at achieving low glide avalanche and maintaining low stictionllong durability by optimizing the bump shape with bump pattern in laser-texture design. A cost-effective method is to re-shape the circular Gaussian laser beam into elliptical Gaussian beam to produce elliptical-shaped bumps which have streamlined open front edge, gradual increasing height profile, and reduced real contact area, to help reduce stiction and geometry-induced glide resonance, which may be critical for future ultra-low-flying head-disk-interfaces. %

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