Particle shape characterization of brown corundum powders by SEM and image analysis

Brown corundum powder, as an abrasive, was prepared by milling of brown corundum ingots by using various crushers. The shape of brown corundum particle is directly related to crusher used and its abrasive property. Thus shape characterization of brown corundum particle is extremely important. In order to investigate the effect of crusher used on particle shape, three shape factors, i.e. Roundness (R), Aspect ratio (AR) and Sharpness (S) were proposed to describe the particle shape in different aspects. And they were calculated using geometrical parameters determined by scanning electron microscopy (SEM) and image analysis. Mean shape factor and shape factor distribution are used to characterize the particle shape of brown corundum powders. This result reflects the actual shape of brown corundum powder particles. Three brown corundum powders were milled by double-roll crusher, ball crusher and cone crusher, respectively. The majority of the particles of powder milled by ball crusher have a larger R, smaller AR and S. However the majority of the particles of powders milled by double-roll crusher or cone crusher, have smaller R, larger AR and S.