Graphite

Graphite (black lead; plumbago CAS: 7782-42-5. HSN : 25041010

The crystalline allotropic form of carbon. Occurs naturally in Madagascar, Ceylon, Mexico, Korea, Austria, USSR, and China. Also produced synthetically by heating petroleum coke to approximately 3000C in an electric resistance furnace. Approximately 70% used in US is synthetic.

Properties: Relatively soft, greasy feel; steel gray to black color with a metallic sheen; d 2.0-2.25 depending upon origin; apparent d artificial graphite 1.5-1.8. High electrical and thermal conductivity, specific heat 0.17 at room tempera- ture, 0.48 at 1500C, tensile strength 400-2000 psi, compressive strength usually approximately 2000-8000 psi. Coefficient of friction 0.1μ. Resistant to oxidation and thermal shock. Sublimes at 3650C.

Grade: Powdered, flake, crystals, rods, plates, fibers.

Hazard: (powder, natural) fire risk. TLV: 2.5 mg/ m³, respirable dust

Use: Crucibles, retorts, foundry facings, molds, lubricants, paints and coatings, boiler com- pounds, powder glazing, electrotyping, mono- chromator in x-ray diffraction analysis, fluori- nated graphite polymers with fluorine to carbon ratios of 0.1-1.25, electrodes, bricks, chemical equipment, motor and generator brushes, seal rings, rocket nozzles, moderator in nuclear reac- tors, cathodes in electrolytic cells, pencils, fi- bers, self-lubricating bearings, intercalation com-
pounds.