Influence of surface defects and edge geometry on the bending strength of slip-cast ZrO2micro-specimens

Abstract Bending tests on slip-cast ceramic micro-specimens made of Y2O3-stabilised ZrO2 of the dimensions 0.2 × 0.2 × 1.2 mm3 were performed. Despite nominally identical feedstock make-up as well as identical parameters for slip-casting, debinding and sintering, the bending strengths of three process batches scatter between 1400 and 3400 MPa. As reasons for the scattering of the mechanical properties, surface defects and differently sized edge radii were determined. Correlations between surface roughness, edge radius and bending strength of the micro-specimens are presented. Additionally, the validity of the Weibull size effect could be confirmed with micro-specimens that have relatively smooth surfaces (peak-to-valley heights Rt between 0.5 and 1.5 mm) and relatively large edge radii (between 11 and 18 mm).