DIAMONDChanaka Wickramasinghe

UndergraduateMineral Resources and technology degree program

Uva Wellassa University of Sri Lanka

The physical properties of diamondDiamond

Has a very high melting point (almost 4000°C). Is very hard. This is again due to the need to break very

strong covalent bonds Doesn't conduct electricity. Is insoluble in water and organic solvents

HARDNESS AND CRYSTAL STRUCTURE Nanometer grain size are harder and tougher Hardness value of 167 GPa - 310 Gpa Hardness is directional: some cases the hardest direction100 times

harder than the softest direction Tensile strength up to 60 GPa Highly lustrous faces Triangular shaped growth defects present Flattest and sharp facets and facet edges

The giant covalent structure of diamond Carbon has an electronic arrangement of 2,4. In diamond each carbon shares electrons with four other carbon atoms

Toughness Ability to resist breakage from falls or impacts Perfect and easy cleavage -> vulnerable to breakage Only fair to good toughness :. Diamond will shatter if hit with an ordinary hammer

Optical propertiesColor and its causes Occur in various colors Substitutional impurities and structural defects, cause the coloration Pure diamonds would be transparent and colorless

Luster ‘Adamantine’ luster The refractive index - 2.417

Optical propertiesFluorescence Emit light of various colors under long-wave ultraviolet light

Optical absorption Visible absorption spectrum consisting of a fine line at 415.5 nm

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Electrical properties Semiconductors due to substitutional boron impurities Good electrical insulator, resistivity of 1011 to 1018 Ωm-1

Magnetic properties observed in diamond nanocrystals

Thermal conductivity• Good conductor of heat• Thermal conductivity of natural

diamond about 22 W/cm·K

Synthetic diamonds A synthetic diamond is a diamond produced through chemical and

physical processes in laboratory conditions

History The earliest successes were reported in 1879

Synthetic diamond is also widely known as HPHT diamond or CVD diamond

Synthetic diamondsManufacturing technologies High pressure, high temperature method Chemical vapor deposition method Detonation of explosives Ultrasound cavitation

Applications Applications are wide range due to the extraordinary properties Widely used in oil and gas drills ‘window’ material for several industrial, R&D, defence and laser

applications Electronic and electrical applications

Applications ‘heat sink’ for sensitive components Optimum exit windows for CO2 lasers In the production of laser optics Industrial and household water treatment Advanced healthcare applications

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Applications As surgical scalpel in ophthalmic and neuro surgery Diamond-based quantum computer technology Essential component in high performance loudspeakers As consumer diamond gemstones.

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