CERAMIC WEAR MAPS - ZIRCONIA

The wear characteristics of an yttria-stabilized zirconia (Y-TZP) are represented by a set of three-dimensional wear maps under dry and lubricated conditions. Water, paraffin oil, and a formulated oil were used as lubricants. Different wear regions were identified as a function of load, speed, and lubrication environment. Sudden increases in wear, identified as wear transitions, were found at certain loads and speeds. The onset of wear transitions was moderated by the presence of a lubricant. Below the wear transitions, the wear was mild and the wear mechanism was predominantly plastic deformation and microfracture. Above the wear transitions, the wear was severe, dominated by brittle fracture and third-body abrasion. Different fluids had different effects on wear. Water had a deleterious effect on wear for this material. The presence of oil lubricants effectively reduced friction and moderated wear. Under high load and high speed, additional stress induced by a thermal gradient within a small area contributed significantly to wear. A critical velocity model was found to describe the locations of the wear transition zones successfully.