Abrasive

Abrasives are extremely commonplace and are used very extensively in a wide variety of industrial, domestic, and technological applications.

However, it is not strictly necessary, as any two solid materials that repeatedly rub against each other will tend to wear each other away; examples include, softer shoe soles wearing away wooden or stone steps over decades or centuries or glaciers abrading stone valleys.

Some factors which will affect how quickly a substance is abraded include: Abrasives may be classified as either natural or synthetic.

Both natural and synthetic abrasives are commonly available in a wide variety of shapes, often coming as bonded or coated abrasives, including blocks, belts, discs, wheels, sheets, rods and loose grains.

Similar issues arise with cutting wheels, which are often structurally reinforced with impregnated fibres.

Traditionally, they were called coolants as they were used to prevent frictional heat build up which could damage the workpiece (such as ruining the temper of a blade).

Dressing is the cleaning of the waste material (swarf and loose abrasive) from the surface and exposing fresh grit.

A bonding agent (often some sort of adhesive or resin) is applied to the backing to provide a flat surface to which the grit is then subsequently adhered.

Coated abrasives may be shaped for use in rotary and orbital sanders, for wrapping around sanding blocks, as handpads, as closed loops for use on belt grinders, as striking surfaces on matchboxes, on diamond plates and diamond steels.

On cars in particular, wax may serve as both a protective agent by preventing exposure of the paint of metal to air and also act as an optical filler to make scratches less noticeable.

Very fine rouge powder was commonly used for grinding glass, being somewhat replaced by modern ceramics, and is still used in jewellery making for a highly reflective finish.

However, many laminate surfaces and ceramic topped stoves are easily damaged by these abrasive compounds.

However, this does take some skill and will eventually cause the protective coating of the disc to be entirely eroded (especially if the original scratch is deep), at which time, the data surface will be destroyed if abrasion continues.

Silicon carbide powders are commonly used as abrasive materials in various machining processes, including grinding, water-jet cutting, and sandblasting.

[6] These powders are effective for fine grinding or rough polishing of semiconductors, ceramics, and ferrous materials.

[7] The shape, size and nature of the workpiece and the desired finish will influence the choice of the abrasive used.

[8] An abrasive which is too hard or too coarse can remove too much material or leave undesired scratch marks.

The final stage of sharpening Japanese swords is called polishing and may be a form of superfinishing.

Different chemical or structural modifications may be made to alter the cutting properties of the abrasive.

Aside from the aforementioned uses of shaping and finishing, abrasives may also be used to prepare surfaces for application of some sort of paint of adhesive.

Inadvertently, people who use knives on glass or metal cutting boards are abrading their knife blades.

The pressure at the knife edge can easily create microscopic (or even macroscopic) cuts in the board.