The single crystal grits used in coated abrasives are similar to the ones used in grinding wheels. Grit sizes are usually graded in larger intervals than for grinding wheels [BORK92, p. 46]. The grits are fully embedded in the bond material, which leads to high resistance against grit-breakout [KONI86, KLOC09, p. 217]. Therefore, the wear mechanisms grit splintering and attritious wear are more common than grit-breakout in belt grinding [KONI86, KLOC09, p. 217].
Besides single crystal abrasives, polycrystalline abrasives are standard for coated abrasive tools. Hollow corundum is a sintered abrasive in the form of a hollow sphere and has proven to be a long-lasting abrasive material for belts [BORK92, p. 46]. Even if the spheres wear, they expose abrasives on their hull and perform uniform cutting action.
Compact bonds are aggregated abrasives in a bond, which can form special shapes. Recently developed examples are pyramid-shaped conglomerates of diamonds in vitrified bond, which are advantageous in lapping [ZHEN10]. The diamond particles are held in a vitreous bond and are shaped like truncated pyramids, which allows a stationary wear [ZHEN10]. The pyramids are fixed with a resin matrix to the backing material [ZHEN10].