Abrasive
Materials used to cut, grind, shape or polish by wearing another material away.
An abrasive works by being harder than what it is cutting, so the requirement is comparative rather than absolute. Hardness alone is not sufficient, though: an abrasive must also fracture in a useful way, presenting fresh sharp edges as it wears rather than going blunt.
That second requirement is why some very hard materials make poor abrasives and why abrasive grain shape and friability are specified as carefully as hardness.
Uses
Grinding wheels, sandpaper, cutting discs, lapping and polishing compounds, and sandblasting. Historically quartz sand and natural emery; now dominated by manufactured silicon carbide and aluminium oxide, with diamond where nothing else will do.
How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.
How this connects
Where a connection has been confirmed by an outside reference, that reference is named beside it.
uses
- Diamond — mineral
- Silicon carbide — compound
- Aluminium oxide — compound
- Corundum — mineral
- Quartz — mineral
- Cerium — element
- Tungsten — element · as tungsten carbide
- Technical ceramic — material · alumina and silicon carbide are the dominant manufactured abrasives
- Osmium — element · osmium-iridium tips resist wear where a point must not blunt
- Tungsten carbide — compound · and as a cutting material, which is the larger use — carbide holds an edge at temperatures that would anneal any steel
- Tool steel — alloy · as the tool rather than the abrasive — cutting, punching and forming everything else
- High-speed steel — alloy · drills, mills and saw blades, tough enough to survive the interruption and vibration that shatters carbide
- Hand axe — object · not as an abrasive but as the edge: the flaked edge is what the stone was selected for
- Silicon nitride — compound · as cutting tool inserts for cast iron and superalloys, where its thermal shock tolerance matters more than its hardness
- Zirconia — compound · as ceramic knives and cutting tools, where transformation toughening stops the chipping that limits other ceramics
- Agate — mineral variety · as mortars, pestles and knife-edge bearings, on hardness and the absence of cleavage rather than as an abrasive itself
- Jasper — mineral variety · knapped as tool stone in the Neolithic, for the same conchoidal fracture that flint and chert were selected for
Sources
- Material WorldOur own writing