Effect of grain size on wear behavior in Y-TZP ceramics

The influence of grain size on the wear behavior of zirconia ceramics was investigated when slided against steel in dry unlubricated conditions. Fully densified Y-TZP ceramics (≥98% of theoretical density) with a wide range of grain size from 75 to 1470 nm were developed using spark plasma sintering (SPS), microwave sintering (MS), and conventional pressureless sintering (CS) methods. SPS was effective in producing fully densified nanocrystalline zirconia at low temperature and short sintering time. The steady state coefficient of friction (COF) varied in a range of 0.35-0.44, but the wear rate reduced from 3.5 to 0.88 × 10−6 mm3/Nm with decreasing grain size. The plastic deformation and microcracking lead to a mild wear for the nanocrystalline zirconia, whereas the delamination/spalling results in the increased wear for the coarser zirconia.