Mechanical strength of different zirconia thin films in relation with their thickness

Zirconia layers with different fractions of tetragonal phase and thicknesses were subjected to multi-cracking tests. Cracks perpendicular to the tensile direction appeared. Cross sections showed that cracks blunt into the substrate. The ratio of crack spacing at saturation to layer thickness decreases when the layer thickness increases. Unit cell modelling has been used to establish a relationship between the crack spacing and the strength of the layer. The relation falls within both bounds of Hu and Evans model. The relation is insensitive to the tetragonal zirconia fraction.

Automated summary

In this study, zirconia layers with different fractions of tetragonal phase and thicknesses were tested for multi-cracking behavior. Cracks perpendicular to the tensile direction were observed, showing a blunting effect into the substrate. The ratio of crack spacing at saturation to layer thickness decreased as the layer thickness increased. Unit cell modeling was used to establish a relationship between crack spacing and layer strength, which fell within the bounds of Hu and Evans model and was found to be insensitive to the tetragonal zirconia fraction.