Types of Abrasives

Abrasives

Abrasives are minerals which are used for polishing or roughening surfaces. They are used to give a finished texture to the work piece by making it shine through polishing or giving it a matte finish through rubbing as in satin. Abrasives are widely used in various purposes like in domestic, technological or industrial applications which include grinding, polishing, buffing, drilling, sharpening, cutting, lapping, sanding, honing etc.

Abrasive Minerals

Abrasives can be either natural or synthetic. Abrasives are generally hard minerals or synthetic stones which cannot be called minerals as they do not arise naturally, but are physically or chemically identical. For example a hard abrasive is diamond, whereas calcium carbonate is a softer abrasive. Abrasives that occur naturally are diamond dust, calcite, novaculite, emery, rouge, sand, pumice dust etc. The synthetic stones that are abrasives are ceramic, ceramic iron oxide, ceramic aluminum oxide, dry ice, glass powder, borazon, steel abrasive, silicon carbide, zircon alumina.

Manufactured Abrasives

Natural and synthetic abrasives come in different shapes which are shaped for various purposes. Abrasives  generally come as bonded or coated which includes blocks, belts, discs, wheels, rods , sheets , loose grains etc.
Bonded abrasive

A matrix which contains an abrasive material is generally a bonded abrasive. Generally the binder is the matrix and it can be clay, glass, resin or rubber. The blocks, sticks or wheels are nothing but the typical shapes given to the mixture of binder and the abrasive. Aluminum oxide is the most usual abrasive. Others are silicon carbide, tungsten carbide and garnet. Generally truing and dressing is done with the bonded abrasives that include activities like cleaning the surface and exposing fresh grit. For example aluminum oxide is used to dress a grinding wheel. Restoring the abrasive to its original surface shape is truing. Generally it is done in wheels and stone that tend to wear unevenly.

Coated abrasives

An abrasive fixed to the backing material is coated abrasive like in a paper, cloth, rubber, metal, polyester which are flexible. A very common coated abrasive is sand paper. The same minerals that are used in bonded abrasives are coated abrasives. To provide a flat surface to the backing a bonding agent is applied. Coated abrasives are the striking surface of the matchbox, closed loops used on belt grinders, on diamond plates and diamond steels etc.

Other abrasives and their uses

To sharpen a knife we generally use a bonded abrasive grind wheel. A brass mirror can be cut with a bonded abrasive and its flattened surface shaped with the coated abrasive.
We can get a lot of information about abrasives through internet. If we are interested in buying the abrasives we can contact the manufacturer online too.