Figure 5.

The remaining strength σ as a function of number of sliding contact cycles n, indentation with a zirconia sphere of radius r = 3.15 mm, at maximum loads P indicated: (a) 3Y-PSZ in water; (b) 5Y-PSZ in water; and (c) combined strength degradation plots. Data points are means and standard deviations, minimum four specimens per point. Filled symbols indicate failure from indentation sites. Unfilled symbols indicate failure from natural flaws. Box at left axis and horizontal solid line are “laboratory” strengths (unindented specimens). Solid curves are theoretical fits to data using Eq. 3.