Surface finish and mechanical strength of dense alumina

Disks of commercial alumina powder were fabricated by slip casting and sintering (1600°C, 2 h). Two different surface treatments were performed: a coarse machining, using a 70 grit diamond wheel (C) and a fine one with SiC paper of 120 and 320 grit (F). In order to study the mechanisms of material deformation and removal and the final superficial features, worn surfaces were analyzed by scanning electron microscopy, profilometry, and residual stress measurements by X-ray diffraction. The fracture strength of the treated specimens was evaluated in biaxial flexure, including a statistical analysis of the data. The results were analyzed, keeping in mind the characteristics of the different surface finishes.