Dry sliding wear of zirconia-toughened alumina with different metal oxide additives

Tribological behaviour of zirconia-toughened alumina (ZTA) with different metal oxide additives was studied. Solid oxide lubricants (MOx; M = Cu, Ti, Mg, Zn, Mn) were added in small quantities (∼8–11 wt%) to provide a self-lubrication action and thereby to decrease the coefficient of dry friction. Dry mixed ceramic composites powders were compacted and pressureless sintered at different temperatures. Densification studies show that near full densities (>97%) were obtained for ZTA ceramic containing both TiO2–CuO and TiO2–MnO2 at 1450 °C. Phase and qualitative compositional analysis was done using X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS). Tribological behaviour of the various ZTA composites was tested by dry sliding the different specimens against SiC abrasive grit paper at a load of 50 N. The lowest specific wear rate of 9.2 × 10−5 mm3/N m and coefficient of friction of 0.35 were observed for the ZTA ceramic composite with TiO2–MnO2. The basic wear mechanisms were abrasion and grain pullout as corroborated from scanning electron microscopy (SEM) images.