Influence of sintering parameters on tribological properties of ceria stabilized zirconia bio-ceramics

Nano-structured ceria stabilized zirconia powder was synthesized from their respective nitrate salts using a wet chemical co-precipitation method. Dried powder was calcined at different temperatures. Particle size of calcined powders was measured by X-ray diffraction (Scherrer equation) and high resolution transmission electron microscopy. Relative quantities of phases (e.g. monoclinic, tetragonal and cubic) were estimated using rigorous Rietveld analysis. The powder was compacted and sintered conventionally following different time and temperature schedules in order to optimize the sintering schedule for fabrication of dense material. The microstructures of the sintered samples were observed by field emission scanning electron microscopy. Vickers hardness (∼945 VHN) showed appreciable increase (>35%) in the hardness value compared to earlier reported ones. Fretting wear of some of the selected samples was carried out in un-lubricated condition. Wear volume and specific wear rate were estimated and correlated with the microstructure. Fatigue microcrack formation, plastic deformation, grain pull-out and abrasion were found to be the main wear mechanisms.