Figure 3.

Post mortem optical micrographs showing top (occlusal) and bottom (cementation) views of ceramic/polycarbonate bilayers subjected to sliding-contact fatigue with tungsten carbide sphere of radius r = 3.2 mm, in water. (a) Occlusal and (b) cementation views of alumina/polycarbonate bilayer subjected to sliding-contact fatigue at P = 608 N, n _F = 108 cycles. (c,d) Occlusal views of sliding-contact damage sustained in homogeneous alumina and graded GAG following 1 million cyclic loadings at 480 N and 682 N, respectively. (e,f) Occlusal views of alumina and GAG following 1 million sliding-contact cycles at 200 N. The sliding direction is from left to right of the images. In (e) and (f), white dashed lines indicate the position of line mapping by profilometry. The peak-valley curves represent the surface topographic profile.