Hardness of microcrystalline alumina-based grains and its influence in grinding performance

Microcrystalline alumina grains constitute one of the most important families of abrasives for industry. In this work, five commercial abrasive grains manufactured by the three main industrial brands were evaluated in order to elucidate the relation between Knoop hardness and their efficiencies during a surface grinding operation using a vitrified grinding wheel. Differences in hardness of commercial abrasive grains reach up to 46% (10.22 GPa), however, results shown that performance in grinding operation is related with the wheel design parameters, according with the workpiece and the grinding conditions. Structural and morphological characterization was carried out by XRD and SEM to evaluate the relationship between grinding wheel design and the abrasive grains.