Tribology of different ceramic sliders on lubricated thin-film disks

Seventy percent straight-rail, taper-flat sliders were made from Al2O3 TiC, Mn . Zn ferrite, SiC, Si3N4 and ZrO2 and tested on lubricated thin-film disks. The tests involved low speed (0.44 m/s) continuous contact drag testing at a fixed radius for a maximum of one million revolutions or to disk failure. SiC did not cause the disk media to fail, even out to five million revolutions, and the friction force had consistently low modulation throughout the test. Si3N4 did not cause any disk failures but exhibited higher friction force with more modulation. Al2O3 TiC, Mn . Zn ferrite and ZrO2 exhibited high failure rates (>50%), even though the initial friction forces were low. The failure rates of these ceramics can be explained by the catalytic activity of Al2O3, TiC, Fe2O3 and ZrO2 on the degradation of the disk lubricant. Another explanation is the localized surface oxidation of SiC and Si3N4 sliders resulted in a softer slider material exhibiting more wear, leading to higher contact area and lower con tact stresses at the slider/disk interface.