From ArticleWorld

Abrasives are materials in the form of grinding wheels, sandpapers and diamond used in order to wear away or polish the surface of a certain other material. Thus abrasives are essentially hard and rough materials, available in both natural and synthetic forms, and used in almost every manufacturing industry and households.

Applications of abrasives

In households, abrasives are used as cleansers for utensils and working counters. Floors, depending on their make and quality may also be cleaned using appropriate abrasive cleansers. In the manufacturing industry, grinding is the most common application of abrasives. It may so happen that a certain product has very narrow dimensional tolerance limits specified. In such cases, grinding mechanisms are used. Apart from this, grinding is necessary for maintaining and sharpening tools used in various stages of manufacturing of products like machine parts, screws, bolts, nuts, etc. All tools fitted to lathe machines, for example, are maintained using grinding tools.

Grinding wheels may spin at speeds in excess of 40 metres per second and throw a stream of sparks. Grinding wheels smaller than a millimetre in diameter are used to grind minute ball bearings.

In the automotive industry, abrasives are deployed to maintain tight-fit between piston rings and the cylinder of an internal combustion engine. An engine bearing requires a smooth, frictionless finish for optimum performance; and this is achieved by the use of abrasives. Valves also need to be polished.

There are other abrasive products too. Sandpapers are used before painting metals and walls. Glass beads and steel wool are used for getting rid of rust, surface dirt or scale.

Types of abrasives – natural and synthetic

Natural abrasives have been in use right from the time of the ancient Greeks and Romans, who used hard, rough stones and emery to polish precious gems, marble and metals. Some of the important abrasives used through the ages and in modern times as well are corundum, diamond, garnet, pumice, talc, quartz and sandstone. Certain vegetable fibres too are known to possess abrasive properties. Sandpaper, a very inexpensive abrasive, uses granulated sand stuck on a paper base. Diamond is the most expensive abrasive. Pumice (solidified lava foam) is another important natural abrasive.

It was in the early 20th century that research on synthetic abrasives began to gather pace. The importance of synthetic abrasives as a better alternative to natural materials came to the fore after the invention of synthetic diamonds. This happened in 1955 when a GE team showed how artificially prepared diamonds could be used as an abrasive, for applications such as drill and tool sharpening. Silicon carbide, aluminium oxide and boron carbide are other inexpensive synthetic abrasives.


Hardness is measured on the Mohs scale from 1 to 10 as suggested by the German mineralogist Friedrich Mohs. Diamond, the hardest known substance is rated 10; while talc, the softest, has a rating of 1.