Carbon materials

carbon-materials

7 materials across 4 types

About carbon materials

Carbon materials (graphite, glassy carbon, pyrolytic graphite, graphene, graphene oxide, carbon nanotubes, carbon fibre): density, conductivity and strength with sources.

Carbon forms very different materials depending on how its atoms are arranged: soft graphite, hard glassy carbon, single-layer graphene, tubes and strong fibres. They are used for electrodes, heat spreaders, crucibles, composites and batteries.

At a glance

Highest density: Structural graphite (Gr-S) reaches 2.27 g/cm³. Lowest: Glassy carbon (GC) starts at 1.42 g/cm³. (4 of 7 grades have a sourced value.)
Highest electrical resistivity: Pyrolytic graphite (PG) reaches 0.000014 Ω·m. Lowest: Structural graphite (Gr-S) starts at 0.000011 Ω·m. (2 of 7 grades have a sourced value.)

Ranges run across the conditions each source reports (temper, heat treatment, form), measured at room temperature where the source says so.

How they compare

The same measurements for every material in the collection. A range means the grade has values under several conditions; "at least" means the source gives a specified minimum. "no data" means no sourced value yet. For ranked tables, open a benchmark.

Carbon materials: how the grades compare
Material	Density	Melting point	Electrical resistivity	Thermal conductivity	Young's modulus	Thermal expansion
Structural graphite (Gr-S)isostatic and extruded rigid graphite blocks, flexible graphite foil and highly oriented pyrolytic graphite (HOPG), used for heat spreading, seals, bearings, electrodes and high-temperature parts	1.72 to 2.27 g/cm³	no data	0.000011 to 0.000012 Ω·m	8 to 1,800 W/(m·K)	14 GPa	6 ppm/K
Glassy carbon (GC)dense amorphous carbon for crucibles, electrodes and high-temperature labware	1.42 to 1.54 g/cm³	no data	45 to 50 ohm µm	4.6 to 6.3 W/(K.m)	35 GPa	2.5 to 2.6 ppm/K
Pyrolytic graphite (PG)thermally anisotropic carbon, deposited from hydrocarbon gas and used for heat spreading and atomic-oxygen tests in orbit	2.25 g/cm³	3,650 °C	0.000014 Ω·m	10 to 1,700 W/(m·K)	4.8 GPa	0.6 to 4.3 ppm/K
Graphene2D carbon sheet (single-layer and few-layer), also sold as graphene nanoplatelets	no data	no data	no data	160 to 5,000 W/(m·K)	no data	no data
GO, rGOOxidised graphene sheet (GO) and its reduced form (rGO), used as membranes, composites and coatings	no data	no data	no data	10 W/(m·K)	6 to 250 GPa	no data
Carbon nanotubes (CNT)Rolled sheets of carbon (single-wall, multi-wall) and macroscopic CNT yarns and sheets	no data	no data	no data	1,750 to 5,800 W/(m·K)	14 to 68 GPa	no data
CFreinforcing fibre	1.77 to 2.12 g/cm³	no data	no data	9.37 to 140 W/(m·K)	135 to 634 GPa	-0.38 ppm/K

What these materials are made of

Composition by weight, as printed in the sources for each grade (the first constituents listed).

Composition of each grade
Material	Main constituents
Glassy carbon (GC)	C 100.0%
Pyrolytic graphite (PG)	C 100.0%
Graphene	C 100.0%
Carbon nanotubes (CNT)	C 100.0%

Where they are used

Uses
Use	Grades
High-temperature crucible for zone refining of gallium arsenide	Glassy carbon (GC)
Electrode for electrochemistry and chemically modified sensors	Glassy carbon (GC)
Heat spreader on AlGaN/GaN transistors	Graphene
Heat spreader on thermal evaluation chips	Graphene
Heat spreaders in silicon-on-insulator circuits	Graphene
GO and polyvinyl alcohol composite (laboratory)	GO, rGO
Reduced GO films as transparent conductors and in field-effect transistors (research)	GO, rGO
GO and rGO films as low-conductivity thermal layers (research)	GO, rGO
Fully printed all-carbon thermoelectric generator on flexible Kapton	Carbon nanotubes (CNT)
Self-powered CNT composite strain sensor	Carbon nanotubes (CNT)
Space Shuttle Orbiter wing leading edge and nose cap (reinforced carbon/carbon)	CF
Compressed gas storage tanks (natural gas, hydrogen)	CF
Automotive, marine, sports and civil engineering parts	CF

When each grade fits

Best use and weak spots of each grade
Material	Best for	Weakest at
Structural graphite (Gr-S)	Dense, machinable graphite blocks for electrodes, seals, bearings and high-temperature parts, and thin foils that spread heat in one plane	Oxidation in air from about 700 °C, and strong anisotropy in foils and HOPG: heat and electricity cross the layers far less well than they travel along them
Glassy carbon (GC)	High-temperature crucibles and electrodes that must resist attack by acids, alkalis and melts	Hard and brittle, and it oxidises in air above about 500 to 600 °C
Pyrolytic graphite (PG)	Heat spreading in one direction, where a thin, light carbon layer must carry heat away along its plane	Strong anisotropy: heat conducts poorly across the layers, and the material is costly to make at high temperature
Graphene	Ideal single-layer mechanics and electronics, where a very high carrier mobility or stiffness per unit mass is the goal	Commercial material properties were not verified in this run, so real nanoplatelet performance is not established here
GO, rGO	Water-permeable membranes, polymer composites and films where an insulating or water-dispersible carbon sheet is wanted	Electrical and thermal performance: GO is an insulator, and reduced GO depends on the reduction route, so no single value describes it
Carbon nanotubes (CNT)	Ideal single-tube stiffness and strength on paper; macroscopic CNT yarns for electrically conductive, lightweight fibre (the review reports conductivity above 10^5 S/m for yarns)	Real macroscopic yarns are far weaker than ideal tubes (0.8 GPa twisted yarn against 150 GPa ideal), and handling of loose CNT material is a health concern (HSE)
CF	Stiffness and strength per unit mass along the fibre: 390 GPa at 1.79 g/cm3 for Tenax UMS40 (datasheet values)	Oxidation in air above about 500 C when uncoated (NASA), and very low strain to failure in the pitch-based K63712 (0.4 %)