diamond and graphite

8/3/2019 Diamond and Graphite

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Diamond and Graphi


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In mineralogy , diamond (from the ancient Greek admas "unbreakable") is an allotrope of carbon , where the carbon atoms are arranged in a

variation of the face-centered cubic crystal structure called a diamond lattice .


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diamond has the highest hardness and thermal

conductivity of any bulk material.Those properties determine the major industrial application of diamond in cutting and polishing

tools .

Diamond has remarkable optical characteristics.Because of its extremely rigid lattice, it can be

contaminated by very few types of impurities, such as boron and nitrogen . Combined with wide transparency, this results in the clear, colorless appearance of most natural diamonds.


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Diamond is the hardest known natural material on the Mohs scale of mineral hardness

, where hardness is defined as resistance to scratching and is graded between 1 (softest) and 10 (hardest).Diamond has a hardness of 10 (hardest) on this scale.[15] Diamond's hardness has been known since antiquity,and is the source of its name.Diamond hardness depends on its purity, crystalline perfection and orientation: hardness is higher for flawless, pure crystals oriented to the direction (along the longest diagonal of the cubic diamond lattice).[16] Therefore, whereas it might be possible to scratch some diamonds with other materials, such as boron nitride , the hardest diamonds can only be scratched by other diamonds and nanocrystalline diamond aggregates .


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Diamonds in the jewelry business are most popularly used

engagement or wedding rings, although it has been used in many other jewelry forms as well. Diamonds are usually sein metals that emphasize its natural beauty and sparkle,most common of which are white gold, yellow gold and platinum.But diamonds have other practical uses as well. Actually,more of these gems are used in industrial applications, rath

than in the jewelry making business, as not a lot of natural diamonds found in mines are suitable as gemstones.


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S ynthetic diamonds, or those that are man-made in a laboratory, are also produced to meet the demands of industrial use. These uses are mainly the following:- cutting and grinding tools such as drill bits and saws - abrasives that cut and polish other materials, including other gemstones - fine engraving tools with detailed precision - coatings for files

- semiconductor coatings and materials for microchips and computer process- laser components for precise and durable optical equipment - windows that are used to cover openings of lasers, x-rays and vacuum chambers - speaker domes that enhance the performance of high quality speakers - heat sinks to conduct heat away from sensitive parts of high performance microelectronics - low friction micro-bearings placed in tiny mechanical devices like watches


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GRAPHITE


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Graphite may be considered the highest grade of coal , just

above anthracite and alternatively called meta- anthracite, although it is

not normally used as fuel because it is difficult to ignite .


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here are three principal types of natural graphite, each occurring in different types of ore deposit:Crystalline flake graphite (or flake graphite for short) occurs as isolated, flat, plate-like particles with hexagonal edges if unbroken and when broken the edgescan be irregular or angular; Amorphous graphite occurs as fine particles and is the result of thermal metamorphism of coal, the last stage of coalification, and is sometimes called meta-anthracite. Very fine flake graphite is sometimes called amorphous in thetrade;

Lump graphite (also called vein graphite) occurs in fissure veins or fractures and appears as massive platy intergrowths of fibrous or acicular crystalline aggregates , and is probably hydrothermal in origin.


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N atural graphite is mostly consumed for refractories, steelmaking, expanded graphite, brake linings, foundry facings and lubricants.Graphene ,which occurs naturally in graphite, has unique physical properties and might be one of the strongest substances known; however, the process

of separating it from graphite will require some technological development before it is economically feasible to use it in industrial processes


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diamond and graphite

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