Facts about Graphite: Applications & Uses
Graphite is a naturally-occurring form of crystalline carbon. It is a native element mineral found in metamophic and igneous rocks. Graphite is a mineral of extremes. It is extremely soft, cleaves with very light pressure, and has a very low specific gravity. In contrast, it is extremely resistant to heat and nearly inert in contact with almost any other material. These extreme properties give it a wide range of uses in metallurgy and manufacturing.
Applications & Common Uses of Graphite
Carbon Brushes (electrical conductivity and low friction and self-lubrication).
- Carbon brushes for electrical motors are manufactured from high purity synthetic graphite.
- Copper-graphite and silver-graphite impregnated composites are used in applications where high electrical conductivity is required: railway technology, wind turbine generators, tacho generators.
Refractories (thermal resistance, thermal conductivity and low wettability by liquid metals).
- Magnesia-carbon bricks for lining steel making furnaces contain up to 25% of graphite.
- Alumina-carbon composites are used in ladles for liquid steel, pouring nozzles, sliding gates.
- Clay-graphite and silicone carbide-graphite composites containing natural coarse flake graphite are used for manufacturing thermocouple and heater tubes, foundrty tools and crucibles for melting non-ferrous metals.
- Facing sand in Sand Casting contains flake graphite to prevent sticking of sand particles to the casting surface.
Electrodes for electric arc furnaces (thermal resistance and electric conductivity).
Molds for continuous casting from isostatically pressed graphite(thermal conductivity, thermal resistance, low friction and self-lubrication, low wettability).
Lubricants (low friction and self-lubrication).
- Graphite powder as a solid lubricant.
- Graphite powder added to oils and greases.
- Polymer coatings containing graphite powder.
- Bronze-graphite composites for sliding bearings.
Friction materials (low friction, self-lubrication, thermal conductivity, thermal resistance) contain up to 15% graphite powder for controlling coefficient of friction and dissipation of friction energy.
- Brake drums and pads.
Graphite Foil (thermal resistance, chemical resistance) is made of a graphite powder treated by sulfuric acid and rolled to a required thickness. Graphite foil is used for manufacturing high temperature gaskets and packages.
Cathodic material in zinc-carbon and lithium-ion batteries (electrical conductivity and chemical resistance) contain fine high purity graphite powder.
Moderators in nuclear reactors (resistance to neutron radiation, thermal resistance).
Carbon fibers for Carbon Fiber Reinforced Polymer Composites (high strength, low density). Automotive, marine and aerospace parts, sport goods (golf clubs, skis, tennis racquets, fishing rods), bicycle frames are made of Carbon Fiber Reinforced Polymer Composites.
Carbon-Carbon Composites (low CTE, high Modulus of Elasticity and strength, low density). High performance braking systems, refractory components, hot-pressed dies, heating elements, turbojet engine components.
Pencils (low friction) consist of a mixture of microcrystalline graphite and clay.
Physical Properties of Graphite
Chemical Classification – Native element
Color – Steel gray to black
Streak – Black
Luster – Metallic, sometimes submetallic or earthy
Diaphaneity – Opaque
Cleavage – Perfect in one direction
Mohs Hardness – 1 to 2
Specific Gravity – 2.1 to 2.3
Diagnostic Properties – Color, streak, slippery feel, specific gravity
Chemical Composition – C
Crystal System – Hexagonal
Uses of Graphite
- Used to manufacture heat and chemical resistant containers and other objects.
- Battery anodes.
- A dry lubricant.
- The “lead” in pencils.
Graphite Key Properties
- Bulk Density (g/cm3) – 1.3-1.95
- Porosity (%) – 0.7-53
- Modulus of Elasticity (GPa) – 8-15
- Compressive strength (MPa) – 20-200
- Flexural strength (MPa) – 6.9-100
- Coefficient of Thermal Expansion (x10-6 °C) – 1.2-8.2
- Thermal conductivity (W/m.K) – 25-470
- Specific heat capacity (J/kg.K) – 710-830
- Electrical resistivity (Ω.m) – 5×10-6-30×10-6
Mesh Size -200 Mesh
Quantity – 28g
Odor – Odorless
UN Number – UN1325
Solubility Information – Insoluble in water.
Physical Form – Powder, Ultra Superior purity
Percent Purity – 99.9999%
Grade – Ultra superior purity
Chemical Name or Material – Graphite powder, Natural
Assay – (metals basis)
If you’re interested in discussing how Graphite can be used for your application, please feel free to contact our technical team directly.