Full definition
Crystalline allotrope of carbon with a unique layered hexagonal structure where planes slide easily over each other, providing natural solid lubrication (coefficient of friction 0.1-0.2). Key properties: self-lubricating, electrically and thermally conductive (parallel to planes: 100-400 W/m·K), chemically inert to most acids and solvents, stable to extremely high temperatures (sublimes at ~3,600°C in inert atmosphere, oxidizes above 400°C in air). Grades: natural flake graphite (mined), synthetic graphite (petroleum coke processed at 2,500-3,000°C for higher purity and consistency), and expanded/flexible graphite (for gaskets and packings). Applications: compression packings for pumps and valves (-200 to +650°C in non-oxidizing service), braided packing rings, dry lubricant (colloidal graphite in oil or water carrier), EDM electrodes, crucibles for metal melting, brush materials for electric motors, nuclear reactor moderator, and Li-ion battery anodes. Per ASTM C709 for nuclear grade. Brands: SGL Carbon, GrafTech, Poco Graphite.