Carbon fibre (PAN-based, pitch-based) and carbon/carbon CF
Carbon filament, over 99 % carbon for the pitch-based K63712 grade · CAS 7782-42-5
Carbon fibre is a filament of mostly carbon, made by carbonising a precursor fibre.
Evidence level
2 of 5
Lab-measured
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
Strength and stiffness
4100 MPa
Thermal conduction
140 W/(m·K)
Heat tolerance in carbon/carbon
Oxidises above about 500 C
Recipe, share of the weight
- not statedCarbon (element)
- not statedPolyacrylonitrile (PAN) precursor
- not statedCoal-tar pitch precursor
Best for
Stiffness and strength per unit mass along the fibre: 390 GPa at 1.79 g/cm3 for Tenax UMS40 (datasheet values)
Weakest at
Oxidation in air above about 500 C when uncoated (NASA), and very low strain to failure in the pitch-based K63712 (0.4 %)
Risk at a glance
- People Low. Dust irritates; acrylonitrile precursor is carcinogenic
- If it fails High. Oxidation of unprotected carbon/carbon in air
- Corrosion Severe. Uncoated carbon/carbon loses weight fast in air above 500 C, and most above 800 C.
Quick facts: CF
| Property | Value | Basis |
|---|---|---|
| Density | 1.77 to 2.12 g/cm³ | 4 sourced values across conditions |
| Tensile strength | 2,550 to 4,900 MPa | 6 sourced values across conditions |
| Young's modulus | 135 to 634 GPa | 6 sourced values across conditions |
| Thermal conductivity | 9.37 to 140 W/(m·K) | 2 sourced values across conditions |
| Thermal expansion (CTE) | -0.38 ppm/K | 1 sourced value |
| Specific heat | 753 J/(kg·K) | 1 sourced value |
What is the density of Carbon fibre and carbon/carbon (CF)?
Carbon fibre and carbon/carbon (CF) has a density of 1.77 to 2.12 g/cm³. The range covers 4 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the thermal conductivity of Carbon fibre and carbon/carbon (CF)?
Carbon fibre and carbon/carbon (CF) has a thermal conductivity of 9.37 to 140 W/(m·K). The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the coefficient of thermal expansion of Carbon fibre and carbon/carbon (CF)?
Carbon fibre and carbon/carbon (CF) has a coefficient of thermal expansion of -0.38 ppm/K. The source and test conditions are listed in the properties table on this page.
What is the tensile strength of Carbon fibre and carbon/carbon (CF)?
Carbon fibre and carbon/carbon (CF) has a tensile strength of 2,550 to 4,900 MPa. The range covers 6 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the Young's modulus of Carbon fibre and carbon/carbon (CF)?
Carbon fibre and carbon/carbon (CF) has a Young's modulus of 135 to 634 GPa. The range covers 6 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is Carbon fibre and carbon/carbon (CF) used for?
Uses recorded in the sources include Space Shuttle Orbiter wing leading edge and nose cap (reinforced carbon/carbon); Compressed gas storage tanks (natural gas, hydrogen); Automotive, marine, sports and civil engineering parts.
Why it exists
Carbon fibre combines high stiffness and strength with low density. The PAN-based Tenax UMS40 is rated at 4700 MPa and 390 GPa along the fibre, and the Torayca T700S at 4900 MPa and 230 GPa, both at a density of about 1.8 g/cm3. Mitsubishi's pitch-based K63712 is stiffer still, at 92 Msi, but breaks at only 0.4 % elongation and has a higher density of 2.12 g/cm3. The fibre values are bare-filament datasheet values, not laminate values. In air, the carbon itself is the weak point above about 500 C, which is why carbon/carbon for the Space Shuttle leading edges was used with a SiC coating.
Where it's used
Launcher heat shields
NASA describes reinforced carbon/carbon as the thermal protection of the wing leading edge and nose cap of the Space Shuttle Orbiter. Those parts were exposed to high-temperature air during re-entry.
Compressed gas tanks
Toray says the T700S suits large-scale production, including compressed gas storage tanks for natural gas and hydrogen.
Structures
Toray names the T700S as the benchmark for automotive, marine, sports and leisure and civil engineering uses.
Recipe
Carbon filament, over 99 % carbon for the pitch-based K63712 grade; PAN-based grades are carbonised polyacrylonitrile
Carbon fibre is made by spinning a precursor into filament, stabilising it and carbonising it to drive off non-carbon elements. For PAN fibre the spun filament is heated to about 300 C in air to oxidise it, then heated in an inert gas to graphitise it (Wikipedia). Pitch-based grades start from coal-tar pitch; K63712 is over 99 % carbon by the Mitsubishi data sheet.
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Carbon (element) | not stated | Forms the graphitic filament. The graphitic layers are aligned along the fibre axis, which gives the strength and stiffness per unit mass. |
| Polyacrylonitrile (PAN) precursor | not stated | Spun into filament, oxidised in air at about 300 C, then carbonised. Its oxidation time, temperature and tension set the final properties. |
| Coal-tar pitch precursor | not stated | Starting material for the pitch-based high-modulus fibre (Mitsubishi calls K63712 coal tar pitch-based). |
Weight shares are as printed in the sources.
What it can do
Strength and stiffness
4100 MPa
measured
Tenax UMS40 is rated at 4700 MPa in tension along the fibre, and T700S at 4900 MPa. Both are bare-fibre typical or nominal values from the datasheets.
Thermal conduction
140 W/(m·K)
The pitch-based K63712 conducts heat at 140 W/(m·K), against 9.37 W/(m·K) for T700S along the fibre (converted from the printed 0.0224 cal/(cm s K)).
Heat tolerance in carbon/carbon
Oxidises above about 500 C
Unprotected carbon/carbon is limited by air oxidation. The SiC coating in the NASA study held weight change to -0.22 % at 900 C in 1 h at 667 Pa air.
How it compares
Along the fibre, the PAN-based grades read here reach 4100 to 4900 MPa and 230 to 390 GPa, with elongation between 1.2 and 2.1 %. The pitch-based K63712 is stiffer (92 Msi) and denser (2.12 g/cm3), and it breaks at only 0.4 %. Carbon/carbon adds heat tolerance but oxidises in air above about 500 C unless it is coated. The table compares the three benchmarks across the PAN and pitch fibres.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details. Compare every grade in the family.
| Measurement | CF |
|---|---|
| Thermal behavior and safety | |
| Specific heat, Torayca T700S carbon fibre | 0.18 Cal/g.°C14 |
| Thermal conductivity, Torayca T700S carbon fibre | 9.37 W/(m·K)15 |
| Thermal conductivity, Mitsubishi K63712 pitch-based fibre | 140 W/(m·K)22 |
| Physical and electrical | |
| Density, Tenax HTA40 E13 3K 200tex fibre | 1.77 g/cm³4 |
| Density, Tenax UMS40 F23 24K 800tex fibre | 1.79 g/cm³8 |
| Density, Torayca T700S carbon fibre | 1.8 g/cm³12 |
| Density, Mitsubishi K63712 pitch-based fibre | 2.12 g/cm³21 |
| Other measurements | |
| Tensile strength, Tenax HTA40 E13 3K 200tex fibre | 4100 MPa1 |
| Tensile modulus, Tenax HTA40 E13 3K 200tex fibre | 240 GPa2 |
| Elongation at break, Tenax HTA40 E13 3K 200tex fibre | 1.7 %3 |
| Tensile strength, Tenax UMS40 F23 24K 800tex fibre | 4700 MPa5 |
| Tensile modulus, Tenax UMS40 F23 24K 800tex fibre | 390 GPa6 |
| Elongation at break, Tenax UMS40 F23 24K 800tex fibre | 1.2 %7 |
| Tensile strength, Torayca T700S carbon fibre (single fibre) | 4900 MPa9 |
| Tensile modulus, Torayca T700S carbon fibre | 230 GPa10 |
| Elongation at break, Torayca T700S carbon fibre | 2.1 %11 |
| Coefficient of thermal expansion, Torayca T700S carbon fibre | -0.38 ppm/K13 |
| Tensile strength, Torayca T700S in a Toray 2500 epoxy composite | 2550 MPa16 |
| Tensile modulus, Torayca T700S in a Toray 2500 epoxy composite | 135 GPa17 |
| Tensile strength, Mitsubishi K63712 pitch-based fibre | 380 ksi18 |
| Tensile modulus, Mitsubishi K63712 pitch-based fibre | 92 Msi19 |
| Ultimate elongation, Mitsubishi K63712 pitch-based fibre | 0.4 %20 |
| Weight change after 0.5 h in air at 500 C, unprotected reinforced carbon/carbon | -2.2 %23 |
| Weight change after 0.5 h in air at 800 C, unprotected reinforced carbon/carbon | -27 %24 |
| Weight change after 0.5 h in air at 1100 C, unprotected reinforced carbon/carbon | -68.6 %25 |
| Weight change after 1 h in air at 1500 C, SiC-coated reinforced carbon/carbon | -3.34 %26 |
| Tensile strength, Tenax UMS45 F22 12K 385tex fibre | 4600 MPa27 |
| Tensile modulus, Tenax UMS45 F22 12K 385tex fibre | 425 GPa28 |
Why choose it, and why not
Good for
- Stiffness per unit mass along known load paths: Tenax UMS40 reaches 390 GPa at 1.79 g/cm3 (Teijin).
- High-temperature heat shields, where the carbon is protected from oxygen: carbon/carbon was used for Space Shuttle leading edges (NASA).
- Compressed gas tanks at high volume: the T700S is produced for that market (Toray).
Watch out for
- Oxidation in air above about 500 C when uncoated (NASA).
- Very low strain to failure in the pitch-based K63712 (0.4 %).
- Fibre values are bare-filament values. Laminate strength is lower, so use the CFRP profile for structures.
Very stiff and strong along the fibre, and light for what it carries. The fibre is not the limit in air. Oxidation above about 500 C is.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Tensile strength, Tenax HTA40 E13 3K 200tex fibre | Typical value printed in the Teijin product overview, MPa column (590 ksi printed alongside) | fibre Tenax HTA40 E13 3K 200tex (PAN-based), bare filamentbasis typical value in the product overview | — |
| 2 | Tensile modulus, Tenax HTA40 E13 3K 200tex fibre | Typical value printed in the Teijin product overview; the German product sheet gives 240 GPa for the same grade | fibre Tenax HTA40 E13 3K 200tex (PAN-based), bare filamentbasis first printed modulus pair (240 GPa, 35 Msi); a second test method in the same row prints 230 GPa (33 Msi) | — |
| 3 | Elongation at break, Tenax HTA40 E13 3K 200tex fibre | Typical value printed in the Teijin product overview | fibre Tenax HTA40 E13 3K 200tex, bare filament | — |
| 4 | Density, Tenax HTA40 E13 3K 200tex fibre | Typical value printed in the Teijin product overview | fibre Tenax HTA40 E13 3K 200tex, bare filament | — |
| 5 | Tensile strength, Tenax UMS40 F23 24K 800tex fibre | Typical value printed in the Teijin product overview, MPa column (680 ksi printed alongside) | fibre Tenax UMS40 F23 24K 800tex (PAN-based, ultra-high modulus), bare filamentsizing S (PU, 1.0 %) | — |
| 6 | Tensile modulus, Tenax UMS40 F23 24K 800tex fibre | Typical value printed in the Teijin product overview; the German product sheet also gives 390 GPa | fibre Tenax UMS40 F23 24K 800tex, bare filamentbasis first printed modulus pair (390 GPa, 57 Msi); the second test method in the same row prints 375 GPa (54 Msi) | — |
| 7 | Elongation at break, Tenax UMS40 F23 24K 800tex fibre | Typical value printed in the Teijin product overview | fibre Tenax UMS40 F23 24K 800tex, bare filament | — |
| 8 | Density, Tenax UMS40 F23 24K 800tex fibre | Typical value printed in the Teijin product overview | fibre Tenax UMS40 F23 24K 800tex, bare filament | — |
| 9 | Tensile strength, Torayca T700S carbon fibre (single fibre) | Nominal value printed in the Toray fibre properties table (test method TY-QA-002) | fibre Torayca T700S (PAN-based), 12k and 24k tows, standard modulusunit in source 500 kgf/mm2 (printed as 4900 (500) MPa (kgf/mm2)) | — |
| 10 | Tensile modulus, Torayca T700S carbon fibre | Nominal value printed in the Toray fibre properties table (test method TY-QA-002) | fibre Torayca T700S (PAN-based)unit in source 23.5 (103 kgf/mm2) | — |
| 11 | Elongation at break, Torayca T700S carbon fibre | Nominal value printed in the Toray fibre properties table (test method TY-QA-002) | fibre Torayca T700S (PAN-based) | — |
| 12 | Density, Torayca T700S carbon fibre | Nominal value printed in the Toray fibre properties table (test method TY-QA-003) | fibre Torayca T700S (PAN-based) | — |
| 13 | Coefficient of thermal expansion, Torayca T700S carbon fibre | Nominal value printed in the Toray functional properties table; 10-6/C equals ppm/K | fibre Torayca T700S (PAN-based), fibre axisunit in source alpha 10-6/C (printed as CTE alpha10-6/C, value -0.38) | — |
| 14 | Specific heat, Torayca T700S carbon fibre | Printed value in Cal/g.C, converted to J/(kg K) on import (1 cal/(g K) = 4184 J/(kg K)) | fibre Torayca T700S (PAN-based)unit in source 0.18 Cal/g.C | — |
| 15 | Thermal conductivity, Torayca T700S carbon fibre | Converted by Space Mushroom: 0.0224 cal/(cm s K) times 418.4 gives 9.37 W/(m K); the printed value is 0.0224 Cal/cm.S.C | fibre Torayca T700S (PAN-based)unit in source 0.0224 Cal/cm.S.C | — |
| 16 | Tensile strength, Torayca T700S in a Toray 2500 epoxy composite | Nominal value printed in the Toray composite properties table; a composite value, not a fibre value | fibre Torayca T700S, Toray 2500 resin (120 C cure), normalised to 60 % fibre volumetemperature room temperaturelayup not stated in the datasheetunit in source 260 kgf/mm2 (printed as 2550 (260) MPa) | — |
| 17 | Tensile modulus, Torayca T700S in a Toray 2500 epoxy composite | Nominal value printed in the Toray composite properties table; a composite value, not a fibre value | fibre Torayca T700S, Toray 2500 resin (120 C cure), normalised to 60 % fibre volumetemperature room temperature | — |
| 18 | Tensile strength, Mitsubishi K63712 pitch-based fibre | Printed value in ksi, converted to MPa on import (1 ksi = 6.894757 MPa) | fibre K63712, coal tar pitch-based carbon fibre, 12k, untwistedunit in source 380 ksi | — |
| 19 | Tensile modulus, Mitsubishi K63712 pitch-based fibre | Printed value in Msi, converted to GPa on import (1 Msi = 6.894757 GPa) | fibre K63712, coal tar pitch-based carbon fibre, 12k, untwistedunit in source 92 Msi | — |
| 20 | Ultimate elongation, Mitsubishi K63712 pitch-based fibre | Typical value printed in the Mitsubishi Chemical America data sheet | fibre K63712, coal tar pitch-based carbon fibre | — |
| 21 | Density, Mitsubishi K63712 pitch-based fibre | Typical value printed in the Mitsubishi Chemical America data sheet | fibre K63712, coal tar pitch-based carbon fibre | — |
| 22 | Thermal conductivity, Mitsubishi K63712 pitch-based fibre | Typical value printed in the Mitsubishi Chemical America data sheet | fibre K63712, coal tar pitch-based carbon fibre | — |
| 23 | Weight change after 0.5 h in air at 500 C, unprotected reinforced carbon/carbon | Weight change printed in NASA oxidation study, Table 2 | material RCC-P3 reinforced carbon/carbon, uncoated, small cubesatmosphere 5 torr airtime 0.5 h | — |
| 24 | Weight change after 0.5 h in air at 800 C, unprotected reinforced carbon/carbon | Weight change printed in NASA oxidation study, Table 2 | material RCC-P3 reinforced carbon/carbon, uncoated, small cubesatmosphere 5 torr airtime 0.5 h | — |
| 25 | Weight change after 0.5 h in air at 1100 C, unprotected reinforced carbon/carbon | Weight change printed in NASA oxidation study, Table 2 | material RCC-P3 reinforced carbon/carbon, uncoated, small cubesatmosphere 5 torr airtime 0.5 h | — |
| 26 | Weight change after 1 h in air at 1500 C, SiC-coated reinforced carbon/carbon | Weight change printed in NASA oxidation study, Table 3 (coated specimens at 500 to 1500 C, two per condition) | material RCC-P3/SiC, SiC conversion coating on all faces, 1.9 cm buttonsatmosphere 667 Pa slowly flowing airtime 1 huncertainty plus or minus 0.57 % as printed | — |
| 27 | Tensile strength, Tenax UMS45 F22 12K 385tex fibre | Typical value printed in the Teijin German product data sheet TSG01de, Zugfestigkeit column (MPa) | fibre Tenax UMS45 F22 12K 385tex (PAN-based, ultra-high modulus), bare filamentsizing PU, 0.9 % | — |
| 28 | Tensile modulus, Tenax UMS45 F22 12K 385tex fibre | Typical value printed in the Teijin German product data sheet TSG01de, Zug-E-Modul column (GPa); the English overview prints the same 425 GPa | fibre Tenax UMS45 F22 12K 385tex, bare filament | — |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Unprotected carbon/carbon in air at 500 to 1100 C (5 torr, 0.5 h) | severe | Uncoated carbon/carbon loses weight fast in air above 500 C, and most above 800 C.1 |
| SiC-coated carbon/carbon in 667 Pa air for 1 h, 500 to 1500 C | moderate | A SiC conversion coating limits weight change, but thermal-expansion cracks let oxygen in.2 |
| Strong oxidisers and peroxides (high-purity carbon fibre thread) | not rated | The SDS warns of violent reactions with strong oxidisers and peroxides.3 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Unprotected carbon/carbon in air at 500 to 1100 C (5 torr, 0.5 h) | Weight change was -2.2 % at 500 C, -27.0 % at 800 C and -68.6 % at 1100 C. The NASA authors describe preferential attack along the fibre edges, and say oxidation begins to be significant above about 500 C. | material RCC-P3 reinforced carbon/carbon, uncoatedatmosphere 5 torr air, 0.5 h |
| 2 | SiC-coated carbon/carbon in 667 Pa air for 1 h, 500 to 1500 C | Weight change was -0.16 % at 500 C, -0.19 % at 700 C, -0.22 % at 900 C and -3.34 % at 1500 C, with no clear oxidation damage at 500 and 700 C. Carbon and SiC expand at different rates, so through-thickness cracks formed in the coating, and cavities formed under cracks at 1100 and 1300 C. | material RCC-P3/SiC, coated on all facesatmosphere 667 Pa slowly flowing air, 1 h |
| 3 | Strong oxidisers and peroxides (high-purity carbon fibre thread) | The Rave SDS lists strong oxidisers and peroxides as incompatible and says violent reactions may occur. It gives no rating or rate. | product High purity carbon fibres in carbon fibre threads (SDS product, not a Tenax or Torayca grade) |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The carbon fibre itself is not classified as hazardous in the SDS read here. Its precursor monomer, acrylonitrile, carries cancer and flammability hazards in PubChem.
- Dust
- Inhaling dust may irritate the respiratory system and dust can cause eye irritation (Rave SDS, section 11). Use goggles and avoid creating dust.
- Precursor monomer
- PubChem reports that acrylonitrile is classified as May cause cancer (H350) and Highly flammable (H225) in most reports. The finished fibre is not the monomer.
If it fails
The failure modes read here are oxidation in air at high temperature, and violent reactions with strong oxidisers.
- Air above 500 C
- Unprotected carbon/carbon lost 27.0 % of its weight in 0.5 h at 800 C and 68.6 % at 1100 C, in 5 torr air (NASA).
- Coating cracks
- A SiC coating limited weight change to -0.22 % at 900 C in 1 h, but cracks from thermal-expansion mismatch let oxygen reach the carbon.
- Oxidisers
- The SDS lists violent reactions with strong oxidisers and peroxides.
Handling and storage
- Keep it dry and closed
- Store in a cool dry place. Torayca T700S shelf life is 24 months from manufacture under ambient conditions.
- Dust
- Avoid creating or accumulating dust. Use breathing protection at high dust concentrations.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Oxidation of unprotected carbon/carbon in airhigh severity | Heating in air at 800 C for 0.5 h (5 torr)Weight loss of 27.0 % at 800 C and 68.6 % at 1100 C; oxidation attacks the fibres along their edges |
| Cracking of the SiC oxidation barrier on carbon/carbonmoderate severity | Carbon and SiC expand at different rates, so through-thickness cracks form in the coatingOxidation-induced cavities form under cracks at 1100 C and 1300 C; weight change at 1500 C was -3.34 % |
| Violent reaction with strong oxidisershigh severity | Contact with strong oxidisers or peroxidesViolent reactions, according to the SDS |
Side effects on surrounding parts
| Affects | Effect |
|---|---|
| Fire crew and the enclosure | The Rave SDS says the product is combustible but will not ignite readily. In a fire it releases carbon monoxide and carbon dioxide. |
Handling and storage
- Store in a cool dry place, away from strong oxidisers and peroxides.
- Avoid creating or accumulating dust. Use breathing protection at high dust concentrations, and safety goggles with side protection.
- Torayca T700S shelf life is 24 months from the month of manufacture if stored under ambient conditions.
Mitigations
- A SiC conversion coating held weight change to -0.16 % at 500 C, -0.19 % at 700 C and -0.22 % at 900 C in 1 h at 667 Pa air, with no clear oxidation damage at 500 and 700 C.
Supply and geography
How common the raw materials are and where they come from.
PAN and pitch precursors (carbon fibre feedstock)
Not applicable: synthetic fibre made from a polymer or pitch precursor; no crustal abundance applies
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
Show the full YAML
spore: profile
id: carbon-fibre
spore_version: 0.2
family: carbon-materials
name: Carbon fibre (PAN-based, pitch-based) and carbon/carbon
abbreviation: CF
role: reinforcing fibre
category: composites
type: carbon-fiber-reinforced
summary: |
Carbon fibre is a filament of mostly carbon, made by carbonising a precursor fibre. The PAN-based grades read here are Teijin Tenax HTA40 and UMS40 and Toray Torayca T700S. Tenax UMS40 is rated at 4700 MPa and 390 GPa along the fibre, and T700S at 4900 MPa and 230 GPa. Mitsubishi's pitch-based K63712 is stiffer, at 92 Msi, but breaks at only 0.4 %. Carbon/carbon, a carbon-fibre composite with a carbon matrix, was used for the Space Shuttle wing leading edge and nose cap, but unprotected material loses weight quickly in air above about 500 C.
best_for: 'Stiffness and strength per unit mass along the fibre: 390 GPa at 1.79 g/cm3 for Tenax UMS40 (datasheet values)'
weakest_at: Oxidation in air above about 500 C when uncoated (NASA), and very low strain to failure in the pitch-based K63712 (0.4 %)
identity:
formula: Carbon filament, over 99 % carbon for the pitch-based K63712 grade; PAN-based grades are carbonised polyacrylonitrile
cas: 7782-42-5
source: toray-t700s
where: Introduction and Fiber Properties table of the Torayca T700S data sheet (grade and density); CAS number is printed on the Rave high-purity carbon fibre SDS (generic carbon CAS, not a grade-specific number)
filament_diameter: Tenax HTA40 7.0 um, Torayca T700S 7.0 um, Tenax UMS40 4.9 um, K63712 11 um (datasheet values)
tags:
environments:
- re-entry
stresses:
- extreme-heat
applications:
- structures
- heat-shields
- propulsion-and-tanks
properties:
- benchmark: ultimate_tensile_strength
label: Tensile strength, Tenax HTA40 E13 3K 200tex fibre
value: 4100
unit: MPa
scope: material
conditions:
fibre: Tenax HTA40 E13 3K 200tex (PAN-based), bare filament
basis: typical value in the product overview
method: Typical value printed in the Teijin product overview, MPa column (590 ksi printed alongside)
status: ground
source: teijin-overview
where: Product overview table, row HTA40 E13 3K 200tex 15Z, tensile strength columns
- benchmark: elastic_modulus
label: Tensile modulus, Tenax HTA40 E13 3K 200tex fibre
value: 240
unit: GPa
scope: material
conditions:
fibre: Tenax HTA40 E13 3K 200tex (PAN-based), bare filament
basis: first printed modulus pair (240 GPa, 35 Msi); a second test method in the same row prints 230 GPa (33 Msi)
method: Typical value printed in the Teijin product overview; the German product sheet gives 240 GPa for the same grade
status: ground
source: teijin-overview
where: Product overview table, row HTA40 E13 3K 200tex 15Z, modulus columns
- benchmark: elongation
label: Elongation at break, Tenax HTA40 E13 3K 200tex fibre
value: 1.7
unit: '%'
scope: material
conditions:
fibre: Tenax HTA40 E13 3K 200tex, bare filament
method: Typical value printed in the Teijin product overview
status: ground
source: teijin-overview
where: Product overview table, row HTA40 E13 3K 200tex 15Z, elongation column
- benchmark: density
label: Density, Tenax HTA40 E13 3K 200tex fibre
value: 1.77
unit: g/cm3
scope: material
conditions:
fibre: Tenax HTA40 E13 3K 200tex, bare filament
method: Typical value printed in the Teijin product overview
status: ground
source: teijin-overview
where: Product overview table, row HTA40 E13 3K 200tex 15Z, density column
- benchmark: ultimate_tensile_strength
label: Tensile strength, Tenax UMS40 F23 24K 800tex fibre
value: 4700
unit: MPa
scope: material
conditions:
fibre: Tenax UMS40 F23 24K 800tex (PAN-based, ultra-high modulus), bare filament
sizing: S (PU, 1.0 %)
method: Typical value printed in the Teijin product overview, MPa column (680 ksi printed alongside)
status: ground
source: teijin-overview
where: Product overview table, row UMS40 F23 24K 800tex S, tensile strength columns
- benchmark: elastic_modulus
label: Tensile modulus, Tenax UMS40 F23 24K 800tex fibre
value: 390
unit: GPa
scope: material
conditions:
fibre: Tenax UMS40 F23 24K 800tex, bare filament
basis: first printed modulus pair (390 GPa, 57 Msi); the second test method in the same row prints 375 GPa (54 Msi)
method: Typical value printed in the Teijin product overview; the German product sheet also gives 390 GPa
status: ground
source: teijin-overview
where: Product overview table, row UMS40 F23 24K 800tex S, modulus columns
- benchmark: elongation
label: Elongation at break, Tenax UMS40 F23 24K 800tex fibre
value: 1.2
unit: '%'
scope: material
conditions:
fibre: Tenax UMS40 F23 24K 800tex, bare filament
method: Typical value printed in the Teijin product overview
status: ground
source: teijin-overview
where: Product overview table, row UMS40 F23 24K 800tex S, elongation column
- benchmark: density
label: Density, Tenax UMS40 F23 24K 800tex fibre
value: 1.79
unit: g/cm3
scope: material
conditions:
fibre: Tenax UMS40 F23 24K 800tex, bare filament
method: Typical value printed in the Teijin product overview
status: ground
source: teijin-overview
where: Product overview table, row UMS40 F23 24K 800tex S, density column
- benchmark: ultimate_tensile_strength
label: Tensile strength, Torayca T700S carbon fibre (single fibre)
value: 4900
unit: MPa
scope: material
conditions:
fibre: Torayca T700S (PAN-based), 12k and 24k tows, standard modulus
unit_in_source: 500 kgf/mm2 (printed as 4900 (500) MPa (kgf/mm2))
method: Nominal value printed in the Toray fibre properties table (test method TY-QA-002)
status: ground
source: toray-t700s
where: Fiber properties table, row Tensile Strength, nominal value
- benchmark: elastic_modulus
label: Tensile modulus, Torayca T700S carbon fibre
value: 230
unit: GPa
scope: material
conditions:
fibre: Torayca T700S (PAN-based)
unit_in_source: 23.5 (103 kgf/mm2)
method: Nominal value printed in the Toray fibre properties table (test method TY-QA-002)
status: ground
source: toray-t700s
where: Fiber properties table, row Tensile Modulus, nominal value
- benchmark: elongation
label: Elongation at break, Torayca T700S carbon fibre
value: 2.1
unit: '%'
scope: material
conditions:
fibre: Torayca T700S (PAN-based)
method: Nominal value printed in the Toray fibre properties table (test method TY-QA-002)
status: ground
source: toray-t700s
where: Fiber properties table, row Elongation, nominal value
- benchmark: density
label: Density, Torayca T700S carbon fibre
value: 1.8
unit: g/cm3
scope: material
conditions:
fibre: Torayca T700S (PAN-based)
method: Nominal value printed in the Toray fibre properties table (test method TY-QA-003)
status: ground
source: toray-t700s
where: Fiber properties table, row Density, nominal value
- benchmark: cte
label: Coefficient of thermal expansion, Torayca T700S carbon fibre
value: -0.38
unit: ppm/K
scope: material
conditions:
fibre: Torayca T700S (PAN-based), fibre axis
unit_in_source: alpha 10-6/C (printed as CTE alpha10-6/C, value -0.38)
method: Nominal value printed in the Toray functional properties table; 10-6/C equals ppm/K
status: ground
source: toray-t700s
where: Functional properties table, row CTE
- benchmark: specific_heat
label: Specific heat, Torayca T700S carbon fibre
value: 0.18
unit: Cal/g.°C
scope: material
conditions:
fibre: Torayca T700S (PAN-based)
unit_in_source: 0.18 Cal/g.C
method: Printed value in Cal/g.C, converted to J/(kg K) on import (1 cal/(g K) = 4184 J/(kg K))
status: ground
source: toray-t700s
where: Functional properties table, row Specific Heat, nominal value
- benchmark: thermal_conductivity
label: Thermal conductivity, Torayca T700S carbon fibre
value: 9.37
unit: W/(m·K)
scope: material
conditions:
fibre: Torayca T700S (PAN-based)
unit_in_source: 0.0224 Cal/cm.S.C
method: 'Converted by Space Mushroom: 0.0224 cal/(cm s K) times 418.4 gives 9.37 W/(m K); the printed value is 0.0224 Cal/cm.S.C'
status: ground
source: toray-t700s
where: Functional properties table, row Thermal Conductivity, nominal value
- benchmark: ultimate_tensile_strength
label: Tensile strength, Torayca T700S in a Toray 2500 epoxy composite
value: 2550
unit: MPa
scope: material
conditions:
fibre: Torayca T700S, Toray 2500 resin (120 C cure), normalised to 60 % fibre volume
temperature: room temperature
layup: not stated in the datasheet
unit_in_source: 260 kgf/mm2 (printed as 2550 (260) MPa)
method: Nominal value printed in the Toray composite properties table; a composite value, not a fibre value
status: ground
source: toray-t700s
where: Composite properties table, row Tensile Strength, footnote on Toray 2500 and 60 % fibre volume
- benchmark: elastic_modulus
label: Tensile modulus, Torayca T700S in a Toray 2500 epoxy composite
value: 135
unit: GPa
scope: material
conditions:
fibre: Torayca T700S, Toray 2500 resin (120 C cure), normalised to 60 % fibre volume
temperature: room temperature
method: Nominal value printed in the Toray composite properties table; a composite value, not a fibre value
status: ground
source: toray-t700s
where: Composite properties table, row Tensile Modulus, footnote as above
- benchmark: ultimate_tensile_strength
label: Tensile strength, Mitsubishi K63712 pitch-based fibre
value: 380
unit: ksi
scope: material
conditions:
fibre: K63712, coal tar pitch-based carbon fibre, 12k, untwisted
unit_in_source: 380 ksi
method: Printed value in ksi, converted to MPa on import (1 ksi = 6.894757 MPa)
status: ground
source: mitsubishi-k63712
where: Typical Properties table, row Tensile Strength
- benchmark: elastic_modulus
label: Tensile modulus, Mitsubishi K63712 pitch-based fibre
value: 92
unit: Msi
scope: material
conditions:
fibre: K63712, coal tar pitch-based carbon fibre, 12k, untwisted
unit_in_source: 92 Msi
method: Printed value in Msi, converted to GPa on import (1 Msi = 6.894757 GPa)
status: ground
source: mitsubishi-k63712
where: Typical Properties table, row Tensile Modulus
- benchmark: elongation
label: Ultimate elongation, Mitsubishi K63712 pitch-based fibre
value: 0.4
unit: '%'
scope: material
conditions:
fibre: K63712, coal tar pitch-based carbon fibre
method: Typical value printed in the Mitsubishi Chemical America data sheet
status: ground
source: mitsubishi-k63712
where: Typical Properties table, row Ult Elongation
- benchmark: density
label: Density, Mitsubishi K63712 pitch-based fibre
value: 2.12
unit: g/cm3
scope: material
conditions:
fibre: K63712, coal tar pitch-based carbon fibre
method: Typical value printed in the Mitsubishi Chemical America data sheet
status: ground
source: mitsubishi-k63712
where: Typical Properties table, row Density
- benchmark: thermal_conductivity
label: Thermal conductivity, Mitsubishi K63712 pitch-based fibre
value: 140
unit: W/(m·K)
scope: material
conditions:
fibre: K63712, coal tar pitch-based carbon fibre
method: Typical value printed in the Mitsubishi Chemical America data sheet
status: ground
source: mitsubishi-k63712
where: Typical Properties table, row Thermal Conductivity
- benchmark: oxidation_weight_change
label: Weight change after 0.5 h in air at 500 C, unprotected reinforced carbon/carbon
value: -2.2
unit: '%'
scope: material
conditions:
material: RCC-P3 reinforced carbon/carbon, uncoated, small cubes
atmosphere: 5 torr air
time: 0.5 h
method: Weight change printed in NASA oxidation study, Table 2
status: ground
source: nasa-rcc-2006
where: Section 3.1, Table 2, row 500
- benchmark: oxidation_weight_change
label: Weight change after 0.5 h in air at 800 C, unprotected reinforced carbon/carbon
value: -27
unit: '%'
scope: material
conditions:
material: RCC-P3 reinforced carbon/carbon, uncoated, small cubes
atmosphere: 5 torr air
time: 0.5 h
method: Weight change printed in NASA oxidation study, Table 2
status: ground
source: nasa-rcc-2006
where: Section 3.1, Table 2, row 800
- benchmark: oxidation_weight_change
label: Weight change after 0.5 h in air at 1100 C, unprotected reinforced carbon/carbon
value: -68.6
unit: '%'
scope: material
conditions:
material: RCC-P3 reinforced carbon/carbon, uncoated, small cubes
atmosphere: 5 torr air
time: 0.5 h
method: Weight change printed in NASA oxidation study, Table 2
status: ground
source: nasa-rcc-2006
where: Section 3.1, Table 2, row 1100
- benchmark: oxidation_weight_change
label: Weight change after 1 h in air at 1500 C, SiC-coated reinforced carbon/carbon
value: -3.34
unit: '%'
scope: material
conditions:
material: RCC-P3/SiC, SiC conversion coating on all faces, 1.9 cm buttons
atmosphere: 667 Pa slowly flowing air
time: 1 h
uncertainty: plus or minus 0.57 % as printed
method: Weight change printed in NASA oxidation study, Table 3 (coated specimens at 500 to 1500 C, two per condition)
status: ground
source: nasa-rcc-2006
where: Section 3.2, Table 3, row 1500
- benchmark: ultimate_tensile_strength
label: Tensile strength, Tenax UMS45 F22 12K 385tex fibre
value: 4600
unit: MPa
scope: material
conditions:
fibre: Tenax UMS45 F22 12K 385tex (PAN-based, ultra-high modulus), bare filament
sizing: PU, 0.9 %
method: Typical value printed in the Teijin German product data sheet TSG01de, Zugfestigkeit column (MPa)
status: ground
source: teijin-tsg01
where: Produktdatenblatt table, row UMS45 F22 12K 385tex
- benchmark: elastic_modulus
label: Tensile modulus, Tenax UMS45 F22 12K 385tex fibre
value: 425
unit: GPa
scope: material
conditions:
fibre: Tenax UMS45 F22 12K 385tex, bare filament
method: Typical value printed in the Teijin German product data sheet TSG01de, Zug-E-Modul column (GPa); the English overview prints the same 425 GPa
status: ground
source: teijin-tsg01
where: Produktdatenblatt table, row UMS45 F22 12K 385tex
corrosion:
- environment: Unprotected carbon/carbon in air at 500 to 1100 C (5 torr, 0.5 h)
headline: Uncoated carbon/carbon loses weight fast in air above 500 C, and most above 800 C.
effect: Weight change was -2.2 % at 500 C, -27.0 % at 800 C and -68.6 % at 1100 C. The NASA authors describe preferential attack along the fibre edges, and say oxidation begins to be significant above about 500 C.
rating: severe
conditions:
material: RCC-P3 reinforced carbon/carbon, uncoated
atmosphere: 5 torr air, 0.5 h
source: nasa-rcc-2006
where: Abstract; Introduction; Section 3.1, Table 2
- environment: SiC-coated carbon/carbon in 667 Pa air for 1 h, 500 to 1500 C
headline: A SiC conversion coating limits weight change, but thermal-expansion cracks let oxygen in.
effect: Weight change was -0.16 % at 500 C, -0.19 % at 700 C, -0.22 % at 900 C and -3.34 % at 1500 C, with no clear oxidation damage at 500 and 700 C. Carbon and SiC expand at different rates, so through-thickness cracks formed in the coating, and cavities formed under cracks at 1100 and 1300 C.
rating: moderate
conditions:
material: RCC-P3/SiC, coated on all faces
atmosphere: 667 Pa slowly flowing air, 1 h
source: nasa-rcc-2006
where: Section 3.2, Table 3; Introduction on coating cracks
- environment: Strong oxidisers and peroxides (high-purity carbon fibre thread)
headline: The SDS warns of violent reactions with strong oxidisers and peroxides.
effect: The Rave SDS lists strong oxidisers and peroxides as incompatible and says violent reactions may occur. It gives no rating or rate.
rating: unknown
conditions:
product: High purity carbon fibres in carbon fibre threads (SDS product, not a Tenax or Torayca grade)
source: rave-cf-sds
where: Sections 10.3 and 10.5
risks:
hazards:
- text: PubChem reports that the acrylonitrile monomer used to make PAN fibre is classified as May cause cancer (H350, 99.8 % of reports), Highly flammable (H225, 99.8 %), Toxic in contact with skin (H311, 97.2 %) and Toxic if inhaled (H331, 97.1 %). This describes the precursor monomer, not the finished fibre.
ghs:
- 'H350: May cause cancer'
- 'H225: Highly flammable liquid and vapour'
- 'H311: Toxic in contact with skin'
- 'H331: Toxic if inhaled'
source: pubchem-acrylonitrile
where: GHS Classification, aggregated reports for CID 7855
- text: The Rave high-purity carbon fibre SDS says the product is not classified for inhalation, skin, eye, sensitisation, mutagenicity or carcinogenicity. It says inhaling dust may irritate the respiratory system and dust can cause eye irritation.
ghs: []
source: rave-cf-sds
where: Section 11 (toxicological information and symptoms)
failure_risks:
- mode: Oxidation of unprotected carbon/carbon in air
trigger: Heating in air at 800 C for 0.5 h (5 torr)
consequence: Weight loss of 27.0 % at 800 C and 68.6 % at 1100 C; oxidation attacks the fibres along their edges
severity: high
source: nasa-rcc-2006
where: Section 3.1, Table 2; Abstract
- mode: Cracking of the SiC oxidation barrier on carbon/carbon
trigger: Carbon and SiC expand at different rates, so through-thickness cracks form in the coating
consequence: Oxidation-induced cavities form under cracks at 1100 C and 1300 C; weight change at 1500 C was -3.34 %
severity: moderate
source: nasa-rcc-2006
where: Section 3.2, Table 3; Introduction
- mode: Violent reaction with strong oxidisers
trigger: Contact with strong oxidisers or peroxides
consequence: Violent reactions, according to the SDS
severity: high
source: rave-cf-sds
where: Sections 10.3 and 10.5
side_effects:
- text: The Rave SDS says the product is combustible but will not ignite readily. In a fire it releases carbon monoxide and carbon dioxide.
affects: Fire crew and the enclosure
source: rave-cf-sds
where: Sections 5.2 and 9.1 (flammability)
mitigations:
- text: A SiC conversion coating held weight change to -0.16 % at 500 C, -0.19 % at 700 C and -0.22 % at 900 C in 1 h at 667 Pa air, with no clear oxidation damage at 500 and 700 C.
source: nasa-rcc-2006
where: Section 3.2, Table 3
handling:
- text: Store in a cool dry place, away from strong oxidisers and peroxides.
source: rave-cf-sds
where: Sections 7.2 and 10.5
- text: Avoid creating or accumulating dust. Use breathing protection at high dust concentrations, and safety goggles with side protection.
source: rave-cf-sds
where: Sections 7 and 8 (control procedures and eye protection)
- text: Torayca T700S shelf life is 24 months from the month of manufacture if stored under ambient conditions.
source: toray-t700s
where: Requirements section
uses:
- application: heat-shields
device: Space Shuttle Orbiter wing leading edge and nose cap (reinforced carbon/carbon)
example: NASA describes reinforced carbon/carbon as the thermal protection of the wing leading edge and nose cap of the Space Shuttle Orbiter.
source: nasa-rcc-2006
where: Introduction, first paragraph
- application: propulsion-and-tanks
device: Compressed gas storage tanks (natural gas, hydrogen)
example: Toray says the T700S suits large-scale production, including compressed gas storage tanks for natural gas and hydrogen.
source: toray-t700s
where: Introduction paragraph of the data sheet
- application: structures
device: Automotive, marine, sports and civil engineering parts
example: Toray names the T700S as the benchmark for automotive, marine, sports and leisure and civil engineering uses.
source: toray-t700s
where: Introduction paragraph of the data sheet
supply:
- subject: PAN and pitch precursors (carbon fibre feedstock)
abundance: 'Not applicable: synthetic fibre made from a polymer or pitch precursor; no crustal abundance applies'
producers: []
manufacture: Torayca T700S is manufactured in France, Japan, the USA and Korea, according to the Toray data sheet. No production shares by country were read in a fetched source.
source: toray-t700s
where: Introduction paragraph of the Torayca T700S data sheet
media: []
documents:
- title: Torayca T700S Carbon Fiber Data Sheet (Toray Carbon Fibers Europe)
type: datasheet
url: https://toray-cfe.com/wp-content/uploads/2025/02/Torayca-T700S-Technical-Data-Sheet.pdf
year: 2024
- title: Tenax filament yarn product overview (Teijin Carbon)
type: datasheet
url: https://www.teijincarbon.com/fileadmin/user_upload/Datenbl%C3%A4tter/Filament_Yarn/EU_Filament_overview.pdf
year: 2026
- title: 'Mitsubishi Chemical America: K63712 coal tar pitch-based carbon fibers, typical properties (hosted by Rockwest Composites)'
type: datasheet
url: https://www.rockwestcomposites.com/media/wysiwyg/PD_K63712.pdf
- title: Oxidation Microstructure Studies of Reinforced Carbon/Carbon (NASA Glenn and Johnson Space Center)
type: report
url: https://ntrs.nasa.gov/api/citations/20060005054/downloads/20060005054.pdf
- title: 'Safety data sheet: High purity carbon fibers in carbon fiber threads, SDS00170CC1016 v4.0 (Rave Scientific)'
type: sds
url: https://ravescientific.com/images/pdf/SDS00170CC1016-01_Carbon_Fibre.pdf
year: 2022
- title: 'PubChem: Acrylonitrile (CID 7855), GHS classification summary'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/Acrylonitrile
gaps:
- 'Country production shares for PAN-based and pitch-based carbon fibre: no readable source found, so none are given.'
- 'Critical-mineral status of acrylonitrile (PAN precursor) and of pitch feedstock: not read.'
- 'Tenax UMS2526 and Mitsubishi K13C2U (about 900 GPa in trade press): only distributor or trade-press figures found, not a datasheet, so not used.'
- Tenax HTA40 and UMS40 values come from the Teijin product overview. Its HTA40 row prints a second modulus of 230 GPa for a different test method; this profile uses the first pair (240 GPa).
- 'Atomic oxygen erosion, UV ageing and thermal-cycling numbers for carbon fibre: not read.'
- 'Density, thermal conductivity and CTE of carbon/carbon (as a composite): not read. Only weight-change figures from the NASA oxidation study are used.'
- Filament diameter is not in the property canon, so it is written in identity only. Weight change under oxidation uses the snake_case name oxidation_weight_change, which is not in the canon either.
- The Rave SDS is for a high-purity carbon fibre thread product (CAS 7782-42-5), not for the Tenax or Torayca production grades. No SDS for a production grade was read.
- Laminate and composite values for Tenax grades were not read. The Toray 2500 composite rows are for T700S only and are normalised to 60 % fibre volume.
- Galvanic coupling of carbon fibre with aluminium is covered in the CFRP profile and is not repeated here.
- 'No media: no image with a checked licence was fetched.'
license: CC-BY-4.0
updated: '2026-10-26'
review:
status: draft
method: assistant
checked_values: 28
unreachable: 2
caveats: 4
note: 'Written by an AI assistant on 2026-10-26 from fetched sources. Unreachable: Teijin standalone HTA40 and UMS fibre data sheets (only the product overview and German sheet were readable); a Mitsubishi K13C2U data sheet. Caveats: UMS40 and HTA40 modulus have two printed test methods; K63712 values converted from ksi and Msi; T700S composite values are composite, not fibre; carbon/carbon values are weight change, not material properties.'
story:
recipe:
line: Carbon fibre is made by spinning a precursor into filament, stabilising it and carbonising it to drive off non-carbon elements. For PAN fibre the spun filament is heated to about 300 C in air to oxidise it, then heated in an inert gas to graphitise it (Wikipedia). Pitch-based grades start from coal-tar pitch; K63712 is over 99 % carbon by the Mitsubishi data sheet.
parts:
- name: Carbon (element)
share: over 99 % in the pitch-based K63712 grade (Mitsubishi data sheet); not stated for the PAN-based grades in the sources read
role: Forms the graphitic filament. The graphitic layers are aligned along the fibre axis, which gives the strength and stiffness per unit mass.
- name: Polyacrylonitrile (PAN) precursor
share: the PAN-based grades' precursor share is not stated in the sources read
role: Spun into filament, oxidised in air at about 300 C, then carbonised. Its oxidation time, temperature and tension set the final properties.
- name: Coal-tar pitch precursor
share: the K63712 precursor share is not stated in the sources read
role: Starting material for the pitch-based high-modulus fibre (Mitsubishi calls K63712 coal tar pitch-based).
risk_groups:
- title: For people
level: 1
verdict: Dust irritates; acrylonitrile precursor is carcinogenic
lead: The carbon fibre itself is not classified as hazardous in the SDS read here. Its precursor monomer, acrylonitrile, carries cancer and flammability hazards in PubChem.
points:
- label: Dust
line: Inhaling dust may irritate the respiratory system and dust can cause eye irritation (Rave SDS, section 11). Use goggles and avoid creating dust.
- label: Precursor monomer
line: PubChem reports that acrylonitrile is classified as May cause cancer (H350) and Highly flammable (H225) in most reports. The finished fibre is not the monomer.
- title: If it fails
lead: The failure modes read here are oxidation in air at high temperature, and violent reactions with strong oxidisers.
points:
- label: Air above 500 C
line: Unprotected carbon/carbon lost 27.0 % of its weight in 0.5 h at 800 C and 68.6 % at 1100 C, in 5 torr air (NASA).
- label: Coating cracks
line: A SiC coating limited weight change to -0.22 % at 900 C in 1 h, but cracks from thermal-expansion mismatch let oxygen reach the carbon.
- label: Oxidisers
line: The SDS lists violent reactions with strong oxidisers and peroxides.
- title: Handling and storage
points:
- label: Keep it dry and closed
line: Store in a cool dry place. Torayca T700S shelf life is 24 months from manufacture under ambient conditions.
- label: Dust
line: Avoid creating or accumulating dust. Use breathing protection at high dust concentrations.
why: Carbon fibre combines high stiffness and strength with low density. The PAN-based Tenax UMS40 is rated at 4700 MPa and 390 GPa along the fibre, and the Torayca T700S at 4900 MPa and 230 GPa, both at a density of about 1.8 g/cm3. Mitsubishi's pitch-based K63712 is stiffer still, at 92 Msi, but breaks at only 0.4 % elongation and has a higher density of 2.12 g/cm3. The fibre values are bare-filament datasheet values, not laminate values. In air, the carbon itself is the weak point above about 500 C, which is why carbon/carbon for the Space Shuttle leading edges was used with a SiC coating.
uses:
- where: Launcher heat shields
line: NASA describes reinforced carbon/carbon as the thermal protection of the wing leading edge and nose cap of the Space Shuttle Orbiter. Those parts were exposed to high-temperature air during re-entry.
- where: Compressed gas tanks
line: Toray says the T700S suits large-scale production, including compressed gas storage tanks for natural gas and hydrogen.
- where: Structures
line: Toray names the T700S as the benchmark for automotive, marine, sports and leisure and civil engineering uses.
can_do:
- label: Strength and stiffness
benchmark: ultimate_tensile_strength
line: Tenax UMS40 is rated at 4700 MPa in tension along the fibre, and T700S at 4900 MPa. Both are bare-fibre typical or nominal values from the datasheets.
- label: Thermal conduction
value: 140 W/(m·K)
line: The pitch-based K63712 conducts heat at 140 W/(m·K), against 9.37 W/(m·K) for T700S along the fibre (converted from the printed 0.0224 cal/(cm s K)).
- label: Heat tolerance in carbon/carbon
value: Oxidises above about 500 C
line: Unprotected carbon/carbon is limited by air oxidation. The SiC coating in the NASA study held weight change to -0.22 % at 900 C in 1 h at 667 Pa air.
compare: Along the fibre, the PAN-based grades read here reach 4100 to 4900 MPa and 230 to 390 GPa, with elongation between 1.2 and 2.1 %. The pitch-based K63712 is stiffer (92 Msi) and denser (2.12 g/cm3), and it breaks at only 0.4 %. Carbon/carbon adds heat tolerance but oxidises in air above about 500 C unless it is coated. The table compares the three benchmarks across the PAN and pitch fibres.
compare_rows:
- label: Strength along the fibres
benchmark: ultimate_tensile_strength
- label: Stiffness along the fibres
benchmark: elastic_modulus
- label: Density
benchmark: density
handling:
- Keep it dry and closed, away from strong oxidisers and peroxides.
- Avoid creating dust. Use goggles and breathing protection at high dust concentrations.
- Check the safety data sheet of the grade you handle, since the SDS read here is for a thread product.
- Torayca T700S shelf life is 24 months from manufacture if stored at ambient conditions.
good_for:
- 'Stiffness per unit mass along known load paths: Tenax UMS40 reaches 390 GPa at 1.79 g/cm3 (Teijin).'
- 'High-temperature heat shields, where the carbon is protected from oxygen: carbon/carbon was used for Space Shuttle leading edges (NASA).'
- 'Compressed gas tanks at high volume: the T700S is produced for that market (Toray).'
watch_out:
- Oxidation in air above about 500 C when uncoated (NASA).
- Very low strain to failure in the pitch-based K63712 (0.4 %).
- Fibre values are bare-filament values. Laminate strength is lower, so use the CFRP profile for structures.
verdict: Very stiff and strong along the fibre, and light for what it carries. The fibre is not the limit in air. Oxidation above about 500 C is.
sources:
toray-t700s:
title: Torayca T700S Carbon Fiber Data Sheet
id: Toray Carbon Fibers Europe, commercial documentation AQ. 866-6, July 2024; test methods TY-QA-002, TY-QA-003
url: https://toray-cfe.com/wp-content/uploads/2025/02/Torayca-T700S-Technical-Data-Sheet.pdf
year: 2024
kind: datasheet
license: manufacturer datasheet, values quoted for reference
teijin-overview:
title: 'Product overview: Tenax and Tenax Next filament yarn (Teijin Carbon)'
id: Teijin Carbon, PDS dated 2026-04-15
url: https://www.teijincarbon.com/fileadmin/user_upload/Datenbl%C3%A4tter/Filament_Yarn/EU_Filament_overview.pdf
year: 2026
kind: datasheet
license: manufacturer datasheet, values quoted for reference
teijin-tsg01:
title: 'Produktdatenblatt: Tenax filament yarn, EU filament (Teijin Carbon Europe)'
id: Teijin Carbon Europe, product data sheet TSG01de, dated 2025-02-15
url: https://www.teijincarbon.com/fileadmin/user_upload/Datenbl%C3%A4tter/Filament_Yarn/Product_Data_Sheet_TSG01de__EU_Filament__de____DE_.pdf
year: 2025
kind: datasheet
license: manufacturer datasheet, values quoted for reference
mitsubishi-k63712:
title: 'K63712: Coal tar pitch-based carbon fibers, typical properties (Mitsubishi Chemical America)'
id: Mitsubishi Chemical America data sheet, undated; hosted by Rockwest Composites
url: https://www.rockwestcomposites.com/media/wysiwyg/PD_K63712.pdf
kind: datasheet
license: manufacturer datasheet, values quoted for reference
nasa-rcc-2006:
title: Oxidation Microstructure Studies of Reinforced Carbon/Carbon
id: NASA NTRS 20060005054; N. S. Jacobson (NASA Glenn), D. M. Curry (NASA Johnson Space Center)
url: https://ntrs.nasa.gov/api/citations/20060005054/downloads/20060005054.pdf
kind: report
license: NASA NTRS public document
rave-cf-sds:
title: 'Safety data sheet: High purity carbon fibers in carbon fiber threads, SDS00170CC1016 v4.0'
id: Rave Scientific, Regulation (EC) No 1907/2006 Art. 31, dated October 5th 2022
url: https://ravescientific.com/images/pdf/SDS00170CC1016-01_Carbon_Fibre.pdf
year: 2022
kind: datasheet
license: supplier safety data sheet, quoted for reference
pubchem-acrylonitrile:
title: 'PubChem compound record: Acrylonitrile (CID 7855), GHS classification summary'
id: CID 7855, National Center for Biotechnology Information
url: https://pubchem.ncbi.nlm.nih.gov/compound/Acrylonitrile
kind: database
license: PubChem public data
wiki-carbon-fibre:
title: 'Carbon fibers (Wikipedia article): composition, history and PAN process only'
id: Wikipedia, article Carbon fibers
url: https://en.wikipedia.org/wiki/Carbon_fibers
kind: web
license: CC BY-SA 4.0
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
| # | Source | Type | Year | Used for |
|---|---|---|---|---|
| Torayca T700S Carbon Fiber Data Sheet | datasheet | 2024 | 14 values | |
| Product overview: Tenax and Tenax Next filament yarn (Teijin Carbon) | datasheet | 2026 | 8 values | |
| Produktdatenblatt: Tenax filament yarn, EU filament (Teijin Carbon Europe) | datasheet | 2025 | 2 values | |
| K63712: Coal tar pitch-based carbon fibers, typical properties (Mitsubishi Chemical America) | datasheet | 5 values | ||
| Oxidation Microstructure Studies of Reinforced Carbon/Carbon | report | 10 values | ||
| Safety data sheet: High purity carbon fibers in carbon fiber threads, SDS00170CC1016 v4.0 | datasheet | 2022 | 6 values | |
| PubChem compound record: Acrylonitrile (CID 7855), GHS classification summary | database | 1 value | ||
| Carbon fibers (Wikipedia article): composition, history and PAN process only | web | 0 values |