Abrasives are those materials used in operations such as grinding, polishing, lapping, honing, pressure blasting or other similar process. Abrasives come in different particle or grit sizes depending on how much material needs to be removed.

Materials used for abrasives are generally characterised by high hardness, and moderate to high fracture toughness.
How They Work

Each hard abrasive particle acts like a single point cutting tool. With hundreds if not thousands available in a small area, the effect they produce is quite significant.

Coarser grades/grits of abrasive are used where high volumes of material need to be removed, such as in coarse polishing, large scratch removal or operations requiring significant shape or dimensional change. Finer grades are generally used after coarser grades to produce a higher surface finish than are possible with coarse grades.
Materials Used for Abrasives

Some materials that are used as abrasives include:

· Silicon carbide, generally used for non-ferrous metals

· Aluminium oxide or alumina, the most widely used abrasive, generally used for ferrous alloys, high tensile materials and wood.

· Diamond, most often used in ceramic grinding or final polishing due to high hardness and cost

· Cubic boron nitride (CBN)

· Garnet, usually used for machining of wood.

· Zirconia/Alumina alloys, suited to carbon and stainless steels and welds

· Glass, usually used for pressure blasting operations.

· Colloidal silica, generally used for finishing operations as it is only available as a suspension of extremely fine particles.