An investigation into the wear mechanism of zirconia-alumina polishing pad under different environments in shape adaptive grinding of WC-Co coating

Shape adaptive grinding (SAG) is a relatively newer finishing process to achieve nanoscale surface roughness of difficult to machine materials. The wear mechanism of zirconia-alumina polishing pads is investigated after performing SAG and chemical assisted SAG (CA-SAG) for the finishing of WC-Co coating. The numbers of active abrasive particles in SAG increases due to the existence of the elastic medium and that leads to a smaller depth of penetration. This phenomenon along with the presence of tough zirconia phase in abrasive particles limits the possibility of the fracture wear. Smooth and elongated grooves along the finishing direction are observed on the wear flats which indicate that the plastic deformation is the predominant wear mechanism rather than micro-fracture. A phenomenological model for the attritious wear of the polishing pads is developed using the experimental findings. The radial pad wear and pad loading are analysed quantitatively using surface texture parameters. The wear mechanism in CA-SAG is immensely affected by the use of chemical reagent in the process. A substantial pad loading is observed owing to the deposition of the passivation layer in the inter-grit spaces. Thus, shelling of the abrasive particles and pad loading are identified as the dominant wear mechanisms.