Deformation of ceria-stabilised tetragonal zirconia ceramics in scratch experiments with a sharp indenter

With a view to understanding the friction and deformation behaviour of tough zirconia polycrystals under conditions of severe contact stress, single pass scratch experiments were conducted with a Vickers indenter on ceria-stabilised tetragonal zirconia ceramics having grain sizes varying from 0·5 to 2·7 μm. For a given grain size, the frictional force, the width, depth and hence the volume of wear groove as well as the transformation zone size (h) all increased with applied normal load (8-20 N). At a given load, the transformation zone size increased with grain size. The deformation behaviour was characterised predominantly by plastic ploughing and to a small extent by other components such as localised microcracking, grain boundary microfracture and chipping. A brief comparison of these results with previous work on alumina, a typical non-phase-transforming ceramic, is also presented, with a view to highlight the distinction in deformation and wear behaviour of the two different type of ceramics.