POCO AXF-5Q isostatic graphite AXF-5Q
C, synthetic isotropic graphite (carbon only)
Also known as AXF-5Q
POCO AXF-5Q is a fine-grain, isotropic synthetic graphite with 5 µm particles and 0.8 µm pores.
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.
Dense, fine-grain block
1.78
Flexural strength
86
Heat conduction
95
Thermal limit
450
Recipe, share of the weight
- C 100.0%Carbon
Best for
Machinable fine-grain graphite for biomedical implant parts, such as the mechanical heart valve and replacement joint components named in the datasheet
Weakest at
Lowest strength of the six POCO graphite grades in the 2014 brochure table, and oxidation in air from 450°C
Risk at a glance
- People None found. Dust limits apply; no safety data sheet was read
- If it fails Moderate. Oxidation in air at high temperature
- Corrosion Moderate. AXF-5Q has a printed oxidation threshold of 450°C in air, the temperature that gives 1% weight loss in 24 hours.
Quick facts: AXF-5Q
| Property | Value | Basis |
|---|---|---|
| Density | 1.78 g/cm³ | 1 sourced value |
| Tensile strength | 62 MPa | 1 sourced value |
| Young's modulus | 11 GPa | 1 sourced value |
| Thermal conductivity | 95 W/(m·K) | 1 sourced value |
| Thermal expansion (CTE) | 7.9 ppm/K | 1 sourced value |
| Electrical resistivity | 0.000015 Ω·m | 1 sourced value |
What is the density of POCO AXF-5Q isostatic graphite?
POCO AXF-5Q isostatic graphite has a density of 1.78 g/cm³. The source and test conditions are listed in the properties table on this page.
What is the thermal conductivity of POCO AXF-5Q isostatic graphite?
POCO AXF-5Q isostatic graphite has a thermal conductivity of 95 W/(m·K). The source and test conditions are listed in the properties table on this page.
What is the coefficient of thermal expansion of POCO AXF-5Q isostatic graphite?
POCO AXF-5Q isostatic graphite has a coefficient of thermal expansion of 7.9 ppm/K. The source and test conditions are listed in the properties table on this page.
What is the tensile strength of POCO AXF-5Q isostatic graphite?
POCO AXF-5Q isostatic graphite has a tensile strength of 62 MPa. The source and test conditions are listed in the properties table on this page.
What is the Young's modulus of POCO AXF-5Q isostatic graphite?
POCO AXF-5Q isostatic graphite has a Young's modulus of 11 GPa. The source and test conditions are listed in the properties table on this page.
What is POCO AXF-5Q isostatic graphite used for?
Uses recorded in the sources include Pyrocarbon-coated graphite parts for replacement joint and mechanical heart valve manufacturers; Precision machined biomedical parts for orthopedic prosthetics and cancer treatments.
Why it exists
POCO AXF-5Q is a fine-grain, isotropic synthetic graphite with 5 µm particles and 0.8 µm pores. Its datasheet prints an apparent density of 1.78 g/cm3, a flexural strength of 86 MPa and an oxidation threshold of 450°C in air. The datasheet and product page present the grade for medical implants, not for aerospace or semiconductor parts, so the aerospace claim sometimes made about this grade is not supported by the sources read.
Where it's used
Mechanical heart valves
The datasheet says AXF-5Q is ideal for pyrocarbon-coated substances used by replacement joint and mechanical heart valve manufacturers.
Orthopedic prosthetics and cancer treatments
The product page lists orthopedic prosthetics and cancer treatments as applications of AXF-5Q, alongside mechanical heart valves.
Recipe
C, synthetic isotropic graphite (carbon only)
AXF-5Q is a synthetic graphite made of carbon only. Graphite is a crystalline form of carbon built from stacked graphene layers, and synthetic graphite is made by graphitising hydrocarbon materials at temperatures in excess of 2,100 °C. POCO's brochure says the manufacture of bulk synthetic graphite leaves tiny voids (pores), which are open if they link to the surface and closed if they are isolated.
| Ingredient | Atoms per unit | Share of the weight | What it does |
|---|---|---|---|
| Carbon C | 1 | 100.0% | The only element. The stacked graphene layers set the basic heat and electrical behaviour. AXF-5Q's uniform, isotropic microstructure, as POCO describes it, makes those properties the same in every direction. |
Weight shares are calculated from standard atomic weights.
What it can do
Dense, fine-grain block
1.78
measured
AXF-5Q has an apparent density of 1.78 g/cm3 on the datasheet, and the 2014 brochure prints the same value.
Flexural strength
86
measured
AXF-5Q has a flexural strength of 86 MPa, measured by the four-point bend method (datasheet footnote 1).
Heat conduction
95
worked out from the formula
The datasheet prints a thermal conductivity of 95 W/m-K. The 2014 brochure labels this value as estimated.
Thermal limit
450
measured
The oxidation threshold is 450°C in air, defined as 1% weight loss in 24 hours on the datasheet.
How it compares
AXF-5Q is the base, unimpregnated grade. Among the six graphite grades in POCO's 2014 brochure table, it has the lowest compressive, flexural and tensile strength, the lowest Shore hardness and the highest open porosity. It also has the lowest oxidation threshold of the grades that print one. Its thermal conductivity is the second highest of the six, behind only the impregnated AXF-5QC. The generic structural graphite profile covers isostatic grades from other makers, and the table below compares this grade on three benchmarks.
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. Other materials are shown beside it; each was measured under its own conditions, so open its page before comparing closely. Compare every grade in the family.
| Measurement | AXF-5Q | Gr-S | GC | PG |
|---|---|---|---|---|
| Thermal behavior and safety | ||||
| Thermal conductivity | 95 W/m-K5 | 105 W m-1 K-1 | 4.6 W/(K.m) | 80 W m-1 K-1 |
| Oxidation threshold in air | 450 °C6 | 500 °C | no data | no data |
| Physical and electrical | ||||
| Apparent densityApparent density, as printed | 1.78 g/cm³1 | 1.72 g/cm³ | 1.54 g/cm³ | 2.25 g cm-3 |
| Shore hardnessShore hardness, as printed | 74 - | no data | no data | no data |
| Electrical resistivityElectrical resistivity, as printed | 1470 µΩ-cm | 12 µΩm | 50 ohm µm | 1375 µOhm cm |
| Other measurements | ||||
| Flexural strengthFlexural strength, as printed | 86 MPa2 | 45 MPa | 210 N/mm2 | no data |
| Compressive strengthCompressive strength, as printed | 138 MPa3 | 90 MPa | no data | no data |
| Tensile strength (manufacturer estimate) | 62 MPa4 | no data | no data | no data |
| Total porosityTotal porosity, as printed | 20 % volume | no data | no data | no data |
| Open porosityOpen porosity, as printed | 80 % of total porosity | 15 Vol. % | no data | no data |
| Particle sizeParticle size, as printed | 5 µm | no data | no data | no data |
| Pore sizePore size, as printed | 0.8 µm | no data | no data | no data |
| Coefficient of thermal expansion | 7.9 µm/m°C7 | 3.2 x10-6 K-1 | 2.5 x10-6 K-1 | 0.6 x10-6 K-1 |
| Modulus of elasticity | 11000 N/mm28 | 14 GPa | 35 kN/mm2 | 4.8 GPa |
| Tensile strain to failure | 0.95 %9 | no data | no data | no data |
Why choose it, and why not
Good for
- Machinable, fine-grain graphite for medical implant parts; the datasheet names mechanical heart valves, orthopedic prosthetics and cancer treatments.
- Precision parts machined from a dense, uniform block; the datasheet says AXF-5Q is easily machined into precision parts.
Watch out for
- Oxidises in air from 450°C. For hot parts, plan a vacuum or inert atmosphere; no test in those atmospheres was found for AXF-5Q.
- Lowest strength of the six POCO graphite grades in the 2014 brochure: 138 MPa compressive, 86 MPa flexural and 62 MPa tensile (the tensile value is an estimate).
- The biocompatibility and FDA wording come from the manufacturer; no independent test was read.
AXF-5Q is a fine-grain, isotropic graphite with a printed density of 1.78 g/cm3 and a printed oxidation threshold of 450°C in air. Its sources describe medical implant use and do not support aerospace or semiconductor claims for this grade. Its strength is the lowest of the six POCO graphite grades in the brochure table, so choose it where machinability and the manufacturer's biocompatibility claims matter, not where high strength matters.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Other names and standards
The same grade under other systems, as datasheets and standards print them. Each code was checked against the page it comes from.
| System | Codes |
|---|---|
| Trade name | AXF-5Q |
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Apparent density | — | grade AXF-5Q, base grade (not impregnated)basis apparent density as printed in the Specifications tabletemperature not stated | — |
| 2 | Flexural strength | — | grade AXF-5Qtest four-point bend method (datasheet footnote 1)temperature not stated | — |
| 3 | Compressive strength | — | grade AXF-5Qtemperature not statedtest not stated | — |
| 4 | Tensile strength (manufacturer estimate) | Printed as an estimate from the flexural result, not a measured tensile test | grade AXF-5Qbasis estimated at 70% of flexural strength (datasheet footnote 2)temperature not stated | — |
| 5 | Thermal conductivity | Printed as 95 W/m-K (55 Btu-ft/hr/ft2 °F) on the datasheet | grade AXF-5Qtemperature not stated | The 2014 brochure marks this value as an estimated value (its footnote 3); the 2021 datasheet prints it without that label. |
| 6 | Oxidation threshold in air | Oxidation threshold, as printed (datasheet footnote 3) | grade AXF-5Qatmosphere air (per brochure footnote 4)definition temperature that results in 1% weight loss in 24 hourssample 0.5 x 0.5 x 1.0 (inches, as printed) | The datasheet says the oxidation threshold increases by approximately 100°C if the graphite is purified. |
| 7 | Coefficient of thermal expansion | Coefficient of thermal expansion, as printed in the brochure table (metric value) | grade AXF-5Qtemperature not stated in the brochure | — |
| 8 | Modulus of elasticity | Modulus of elasticity, as printed in the brochure table | grade AXF-5Qtemperature not stated in the brochure | — |
| 9 | Tensile strain to failure | Tensile strain to failure, as printed in the brochure table | grade AXF-5Qtemperature not stated in the brochure | — |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Air at high temperature (oxygen-containing atmosphere) | moderate | AXF-5Q has a printed oxidation threshold of 450°C in air, the temperature that gives 1% weight loss in 24 hours.1 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Air at high temperature (oxygen-containing atmosphere) | The datasheet gives the threshold as 450°C (840°F) and says it increases by approximately 100°C if the graphite is purified. The 2014 brochure gives the same 450°C (840°F) for AXF-5Q and says graphite is subject to oxidation at high temperatures, typically above 450°C. No AXF-5Q oxidation test in a different atmosphere was printed in the sources read. | atmosphere air (per brochure footnote 4)definition 1% weight loss in 24 hourssample 0.5 x 0.5 x 1.0 (inches, as printed) |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
Graphite dust has OSHA and ACGIH exposure limits. No supplier safety data sheet for AXF-5Q was read in this run, so the hazard picture for the grade itself is incomplete.
- Dust
- OSHA's PEL-TWA for graphite (synthetic) is 15 mg/m3 total dust and 5 mg/m3 respirable fraction. The ACGIH TLV-TWA is 2 mg/m3 for respirable particulate matter.
- Medical grade
- The datasheet calls AXF-5Q biocompatible and says it is suitable for implants. These are manufacturer claims; no independent test was read.
In service
The printed oxidation threshold is 450°C in air, the temperature that gives 1% weight loss in 24 hours. Purifying the graphite raises the threshold by approximately 100°C.
- Oxidation
- The datasheet gives an oxidation threshold of 450°C (840°F) for AXF-5Q in air, defined as 1% weight loss in 24 hours.
- Strength
- The 2014 brochure lists AXF-5Q with the lowest compressive, flexural and tensile strength of the six graphite grades in its table.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Oxidation in air at high temperaturemoderate severity | Sustained exposure in air at the 450°C oxidation thresholdSurface and section loss; the datasheet defines the threshold as the temperature that gives 1% weight loss in 24 hours |
| Lower strength than the other POCO graphite grades in the brochuremoderate severity | Mechanical load on a part made from this gradeThe 2014 brochure table gives AXF-5Q the lowest compressive strength (138 MPa), flexural strength (86 MPa) and tensile strength (62 MPa) of the six graphite grades it lists |
Side effects on surrounding parts
| Affects | Effect |
|---|---|
| Sealing, fluid contact and permeability of parts made from the base grade | Open porosity is 80% of total porosity, so most of the pore network connects to the surface; the brochure defines open porosity as voids that link to the surface. |
| Designers choosing between the base grade and the impregnated grade | The brochure marks impregnated grades with an asterisk. AXF-5Q has no asterisk, and its impregnated sibling AXF-5QC has a higher thermal conductivity and a lower electrical resistivity. |
Handling and storage
- The datasheet prints no handling or storage instructions for AXF-5Q, and no supplier safety data sheet for it was read in this run.
- Keep parts in air below the 450°C oxidation threshold where they must keep their strength.
Mitigations
- Use a purified grade where the oxidation threshold matters: the datasheet says the threshold increases by approximately 100°C if the graphite is purified.
Supply and geography
How common the raw materials are and where they come from.
Natural graphite (USGS mine production; the USGS chapter does not quantify synthetic graphite production)
The USGS says the rest of the world's resources exceed 800 million tons of recoverable graphite.
- Top producers (2025)
- China 77.8%, Madagascar 4.4%, Brazil 3.6%, Mozambique 3.3%
- Critical mineral lists
- US: listed
- Recycling
- USGS: information on the quantity and value of recycled graphite was not available, and the abundance of graphite in the world market inhibits increased recycling efforts.
- Substitutes
- USGS: synthetic graphite powder, scrap from discarded machined shapes and calcined petroleum coke compete for use in iron and steel production; synthetic graphite powder and secondary synthetic graphite from machining compete in battery applications.
Documents
Datasheets, safety data sheets, papers and standards you can open.
| Document | Type | Year |
|---|---|---|
| Entegris AXF-5Q Graphite datasheet (6200-11934ENT-0821, 2021) | datasheet | 2021 |
| POCO Premium Carbon Materials brochure, For the Aerospace Industry (IND-107610-0814) | datasheet | 2014 |
| POCO product page: AXF-5Q, industrial graphite grades | datasheet | 2026 |
| USGS Mineral Commodity Summaries 2026: Graphite (natural) | report | 2026 |
| OSHA chemical data: Graphite (synthetic) | database | 2026 |
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: poco-axf-5q
spore_version: 0.2
family: carbon-materials
name: POCO AXF-5Q isostatic graphite
abbreviation: AXF-5Q
role: Premium fine-grain isotropic synthetic graphite from Entegris POCO, sold as rods, blocks, plates and finished parts; the datasheet presents it for medical implants
category: carbon
type: Graphite
summary: |
POCO AXF-5Q is a fine-grain, isotropic synthetic graphite with 5 µm particles and 0.8 µm pores. Its Entegris datasheet prints an apparent density of 1.78 g/cm3, a flexural strength of 86 MPa (four-point bend) and an oxidation threshold of 450°C in air. The datasheet and product page present the grade for medical implants, and neither names aerospace or semiconductor use for it.
best_for: Machinable fine-grain graphite for biomedical implant parts, such as the mechanical heart valve and replacement joint components named in the datasheet
weakest_at: Lowest strength of the six POCO graphite grades in the 2014 brochure table, and oxidation in air from 450°C
identity:
formula: C, synthetic isotropic graphite (carbon only)
source: wiki-graphite
where: 'Wikipedia Graphite: crystalline allotrope of carbon, made by thermal graphitization in excess of 2,100 °C; grade identity from the Entegris AXF-5Q datasheet title'
designations:
- system: Trade name
code: AXF-5Q
source: poco-axf5q-datasheet
where: Datasheet title and Specifications table
tags:
environments: []
stresses: []
applications: []
properties:
- benchmark: density
label: Apparent density
value: 1.78
unit: g/cm3
scope: material
conditions:
grade: AXF-5Q, base grade (not impregnated)
basis: apparent density as printed in the Specifications table
temperature: not stated
method: Apparent density, as printed
status: ground
source: poco-axf5q-datasheet
where: Specifications table, Apparent density row; the 2014 brochure prints the same 1.78 g/cm3 for AXF-5Q
- benchmark: flexural_strength
label: Flexural strength
value: 86
unit: MPa
scope: material
conditions:
grade: AXF-5Q
test: four-point bend method (datasheet footnote 1)
temperature: not stated
method: Flexural strength, as printed
status: ground
source: poco-axf5q-datasheet
where: Specifications table, Flexural strength row and footnote 1; the 2014 brochure prints 86 MPa
- benchmark: compressive_strength
label: Compressive strength
value: 138
unit: MPa
scope: material
conditions:
grade: AXF-5Q
temperature: not stated
test: not stated
method: Compressive strength, as printed
status: ground
source: poco-axf5q-datasheet
where: Specifications table, Compressive strength row
- benchmark: ultimate_tensile_strength
label: Tensile strength (manufacturer estimate)
value: 62
unit: MPa
scope: material
conditions:
grade: AXF-5Q
basis: estimated at 70% of flexural strength (datasheet footnote 2)
temperature: not stated
method: Printed as an estimate from the flexural result, not a measured tensile test
status: calculated
source: poco-axf5q-datasheet
where: Specifications table, Tensile strength row and footnote 2
- benchmark: shore_hardness
label: Shore hardness
value: 74
unit: '-'
scope: material
conditions:
grade: AXF-5Q
scale: not printed on the datasheet
method: Shore hardness, as printed
status: ground
source: poco-axf5q-datasheet
where: Specifications table, Shore hardness row
- benchmark: electrical_resistivity
label: Electrical resistivity
value: 1470
unit: µΩ-cm
scope: material
conditions:
grade: AXF-5Q
temperature: not stated
method: Electrical resistivity, as printed
status: ground
source: poco-axf5q-datasheet
where: Specifications table, Electrical resistivity row; the 2014 brochure prints 1470 µΩ-cm for AXF-5Q
- benchmark: thermal_conductivity
label: Thermal conductivity
value: 95
unit: W/m-K
scope: material
conditions:
grade: AXF-5Q
temperature: not stated
method: Printed as 95 W/m-K (55 Btu-ft/hr/ft2 °F) on the datasheet
status: calculated
note: The 2014 brochure marks this value as an estimated value (its footnote 3); the 2021 datasheet prints it without that label.
source: poco-axf5q-datasheet
where: Specifications table, Thermal conductivity row; brochure Typical Material Properties table, footnote 3
- benchmark: oxidation_onset_air
label: Oxidation threshold in air
value: 450
unit: °C
scope: material
conditions:
grade: AXF-5Q
atmosphere: air (per brochure footnote 4)
definition: temperature that results in 1% weight loss in 24 hours
sample: 0.5 x 0.5 x 1.0 (inches, as printed)
method: Oxidation threshold, as printed (datasheet footnote 3)
status: ground
note: The datasheet says the oxidation threshold increases by approximately 100°C if the graphite is purified.
source: poco-axf5q-datasheet
where: Specifications table, Oxidation threshold row and footnote 3; the 2014 brochure prints 450°C (840°F) with footnote 4
- benchmark: total_porosity
label: Total porosity
value: 20
unit: '% volume'
scope: material
conditions:
grade: AXF-5Q
basis: as printed
method: Total porosity, as printed
status: ground
source: poco-axf5q-datasheet
where: Specifications table, Total porosity row
- benchmark: open_porosity
label: Open porosity
value: 80
unit: '% of total porosity'
scope: material
conditions:
grade: AXF-5Q
basis: as printed
method: Open porosity, as printed
status: ground
source: poco-axf5q-datasheet
where: Specifications table, Open porosity row
- benchmark: particle_size
label: Particle size
value: 5
unit: µm
scope: material
conditions:
grade: AXF-5Q
basis: as printed (200 µin)
method: Particle size, as printed
status: ground
source: poco-axf5q-datasheet
where: Specifications table, Particle size row
- benchmark: pore_size
label: Pore size
value: 0.8
unit: µm
scope: material
conditions:
grade: AXF-5Q
basis: as printed (32 µin)
method: Pore size, as printed
status: ground
source: poco-axf5q-datasheet
where: Specifications table, Pore size row
- benchmark: cte
label: Coefficient of thermal expansion
value: 7.9
unit: µm/m°C
scope: material
conditions:
grade: AXF-5Q
temperature: not stated in the brochure
method: Coefficient of thermal expansion, as printed in the brochure table (metric value)
status: ground
source: poco-brochure
where: Typical Material Properties table, Coefficient of thermal expansion row, AXF-5Q column
- benchmark: elastic_modulus
label: Modulus of elasticity
value: 11000
unit: N/mm2
scope: material
conditions:
grade: AXF-5Q
temperature: not stated in the brochure
method: Modulus of elasticity, as printed in the brochure table
status: ground
source: poco-brochure
where: Typical Material Properties table, Modulus of elasticity row, AXF-5Q column
- benchmark: tensile_strain_to_failure
label: Tensile strain to failure
value: 0.95
unit: '%'
scope: material
conditions:
grade: AXF-5Q
temperature: not stated in the brochure
method: Tensile strain to failure, as printed in the brochure table
status: ground
source: poco-brochure
where: Typical Material Properties table, Tensile strain to failure row, AXF-5Q column
corrosion:
- environment: Air at high temperature (oxygen-containing atmosphere)
headline: AXF-5Q has a printed oxidation threshold of 450°C in air, the temperature that gives 1% weight loss in 24 hours.
effect: The datasheet gives the threshold as 450°C (840°F) and says it increases by approximately 100°C if the graphite is purified. The 2014 brochure gives the same 450°C (840°F) for AXF-5Q and says graphite is subject to oxidation at high temperatures, typically above 450°C. No AXF-5Q oxidation test in a different atmosphere was printed in the sources read.
rating: moderate
conditions:
atmosphere: air (per brochure footnote 4)
definition: 1% weight loss in 24 hours
sample: 0.5 x 0.5 x 1.0 (inches, as printed)
source: poco-axf5q-datasheet
where: Specifications table, Oxidation threshold row and footnote 3; brochure Oxidation Inhibition text and footnote 4
risks:
hazards:
- text: OSHA's PEL-TWA for graphite (synthetic) is 15 mg/m3 total dust and 5 mg/m3 respirable fraction; the California limit is 10 mg/m3 total dust and 5 mg/m3 respirable fraction.
ghs: []
source: osha-graphite-synthetic
where: PEL-TWA lines, OSHA chemical data page for GRAPHITE (SYNTHETIC)
- text: The ACGIH TLV-TWA for graphite (synthetic) is 2 mg/m3 for respirable particulate matter, as listed on the same OSHA page.
ghs: []
source: osha-graphite-synthetic
where: ACGIH line, OSHA chemical data page for GRAPHITE (SYNTHETIC)
failure_risks:
- mode: Oxidation in air at high temperature
trigger: Sustained exposure in air at the 450°C oxidation threshold
consequence: Surface and section loss; the datasheet defines the threshold as the temperature that gives 1% weight loss in 24 hours
severity: moderate
source: poco-axf5q-datasheet
where: Specifications table, Oxidation threshold row and footnote 3
- mode: Lower strength than the other POCO graphite grades in the brochure
trigger: Mechanical load on a part made from this grade
consequence: The 2014 brochure table gives AXF-5Q the lowest compressive strength (138 MPa), flexural strength (86 MPa) and tensile strength (62 MPa) of the six graphite grades it lists
severity: moderate
source: poco-brochure
where: Typical Material Properties table, strength rows, AXF-5Q column
side_effects:
- text: Open porosity is 80% of total porosity, so most of the pore network connects to the surface; the brochure defines open porosity as voids that link to the surface.
affects: Sealing, fluid contact and permeability of parts made from the base grade
source: poco-axf5q-datasheet
where: Specifications table, Open porosity row; brochure Densification paragraph
- text: The brochure marks impregnated grades with an asterisk. AXF-5Q has no asterisk, and its impregnated sibling AXF-5QC has a higher thermal conductivity and a lower electrical resistivity.
affects: Designers choosing between the base grade and the impregnated grade
source: poco-brochure
where: Typical Material Properties table, AXF-5Q and AXF-5QC columns, and asterisk note
handling:
- text: The datasheet prints no handling or storage instructions for AXF-5Q, and no supplier safety data sheet for it was read in this run.
source: poco-axf5q-datasheet
where: Whole document; ordering information and terms of sale only
- text: Keep parts in air below the 450°C oxidation threshold where they must keep their strength.
source: poco-axf5q-datasheet
where: Specifications table, Oxidation threshold row
mitigations:
- text: 'Use a purified grade where the oxidation threshold matters: the datasheet says the threshold increases by approximately 100°C if the graphite is purified.'
source: poco-axf5q-datasheet
where: Specifications table, footnote 3
uses:
- application: structures
device: Pyrocarbon-coated graphite parts for replacement joint and mechanical heart valve manufacturers
example: The datasheet says AXF-5Q is ideal for pyrocarbon-coated substances used by replacement joint and mechanical heart valve manufacturers around the world.
source: poco-axf5q-datasheet
where: Opening text and APPLICATIONS list (Mechanical heart valves), first page
- application: structures
device: Precision machined biomedical parts for orthopedic prosthetics and cancer treatments
example: The POCO product page lists Orthopedic prosthetics and Cancer treatments under Applications, next to Mechanical heart valves, and says the grade is further processed for targeted applications such as in the biomedical field.
source: poco-axf5q-web
where: Applications heading and product description on the AXF-5Q product page
supply:
- subject: Natural graphite (USGS mine production; the USGS chapter does not quantify synthetic graphite production)
abundance: The USGS says the rest of the world's resources exceed 800 million tons of recoverable graphite.
producers:
- country: China
share_percent: 77.8
year: 2025
- country: Madagascar
share_percent: 4.4
year: 2025
- country: Brazil
share_percent: 3.6
year: 2025
- country: Mozambique
share_percent: 3.3
year: 2025
critical_lists:
- list: USGS 2025 List of Critical Minerals (graphite listed; 60 minerals on the final list)
listed: true
recycling: 'USGS: information on the quantity and value of recycled graphite was not available, and the abundance of graphite in the world market inhibits increased recycling efforts.'
substitutes:
- 'USGS: synthetic graphite powder, scrap from discarded machined shapes and calcined petroleum coke compete for use in iron and steel production; synthetic graphite powder and secondary synthetic graphite from machining compete in battery applications.'
source: usgs-mcs2026-graphite
where: 'World Mine Production and Reserves table, 2025e (world total 1,800,000 t, rounded; shares calculated by Space Mushroom from the China, Madagascar, Brazil and Mozambique rows). The USGS text gives China about 82% of world natural graphite on another basis. Critical list: USGS final 2025 list page.'
media: []
documents:
- title: Entegris AXF-5Q Graphite datasheet (6200-11934ENT-0821, 2021)
type: datasheet
url: https://www.entegris.com/content/dam/product-assets/axf5qgraphite/datasheet-axf5qgraphite.pdf
year: 2021
- title: POCO Premium Carbon Materials brochure, For the Aerospace Industry (IND-107610-0814)
type: datasheet
url: https://www.entegris.com/content/dam/shared-product-assets/specialty-shared/datasheet-aerospace-graphite-107610-a4.pdf
year: 2014
- title: 'POCO product page: AXF-5Q, industrial graphite grades'
type: datasheet
url: https://www.poco.entegris.com/en/home/products/premium-graphite/industrial-grades/axf5q.html
year: 2026
- title: 'USGS Mineral Commodity Summaries 2026: Graphite (natural)'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-graphite.pdf
year: 2026
- title: 'OSHA chemical data: Graphite (synthetic)'
type: database
url: https://www.osha.gov/chemicaldata/533
year: 2026
gaps:
- No supplier safety data sheet or PubChem GHS record for AXF-5Q was read in this run (the PubChem page returned a browser check), so the ghs lists are empty.
- The two uses[] entries (mechanical heart valves and replacement joints; orthopedic prosthetics and cancer treatments) are filed under structures, the nearest platform application, because the platform application list has no medical category. The same convention is used in hydroxyapatite.yaml. The application field is therefore a placeholder for a medical use, not a space application.
- The task brief described AXF-5Q as marketed for aerospace and semiconductor parts. The datasheet and product page do not say this. The 2014 POCO brochure is headed For the Aerospace Industry but does not name AXF-5Q as an aerospace grade, so no aerospace or semiconductor use is written in this profile.
- The datasheet prints 'FDA Class II and II applications' (the second class looks like a typo) and calls the grade biocompatible. These are manufacturer statements; no independent test or FDA record was read.
- No vacuum, radiation, atomic-oxygen, thermal-cycling or outgassing result for AXF-5Q was found in the sources read.
- No chemical-resistance result (acids, bases, solvents) and no oxidation result in an inert atmosphere for AXF-5Q was found in the sources read.
- Impurity or ash content of the base AXF-5Q grade is not printed. The brochure's purified-grade figure is for purified POCO grades in general, not AXF-5Q.
- No test temperature is printed for density, strength, hardness, electrical resistivity or thermal conductivity; the brochure lists CTE, modulus and tensile strain with no test temperature either.
- The 2014 brochure is the only source for CTE, modulus of elasticity and tensile strain to failure; the 2021 datasheet does not repeat them.
- Tensile strength of 62 MPa is a manufacturer estimate (70% of flexural strength), not a measured tensile test. Thermal conductivity of 95 W/m-K is labelled as estimated in the 2014 brochure.
- 'Non-canonical property names used because no canonical name fits: compressive_strength, shore_hardness, total_porosity, open_porosity, particle_size, pore_size, oxidation_onset_air and tensile_strain_to_failure.'
- 'Supply: the USGS graphite chapter covers natural graphite and gives no production figure for synthetic graphite, the feedstock class of AXF-5Q. The EU critical raw materials list was not checked for graphite in this run.'
- Carbon atomic weight 12.011 is the Wikipedia Carbon infobox value with its plus-or-minus 0.002 uncertainty; the page prints no unit next to it.
sources:
poco-axf5q-datasheet:
title: Entegris AXF-5Q Graphite datasheet
id: 6200-11934ENT-0821 (copyright 2021 Entegris, Inc.)
url: https://www.entegris.com/content/dam/product-assets/axf5qgraphite/datasheet-axf5qgraphite.pdf
year: 2021
kind: datasheet
license: Entegris datasheet, cited, not reproduced
poco-axf5q-web:
title: 'POCO product page: AXF-5Q, industrial graphite grades'
id: poco.entegris.com, read 2026-11-01
url: https://www.poco.entegris.com/en/home/products/premium-graphite/industrial-grades/axf5q.html
year: 2026
kind: web
license: Manufacturer web page, cited
poco-brochure:
title: POCO Premium Carbon Materials brochure
id: IND-107610-0814 (copyright 2014 Poco Graphite, Inc.)
url: https://www.entegris.com/content/dam/shared-product-assets/specialty-shared/datasheet-aerospace-graphite-107610-a4.pdf
year: 2014
kind: datasheet
license: Manufacturer brochure, cited, not reproduced
usgs-mcs2026-graphite:
title: 'Mineral Commodity Summaries 2026: Graphite (natural)'
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-graphite.pdf
year: 2026
kind: report
license: US government work (public domain)
usgs-critical-2025:
title: About the 2025 List of Critical Minerals (USGS, final list of 60 minerals)
id: Final 2025 List of Critical Minerals
url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
year: 2025
kind: web
license: US government work (public domain)
osha-graphite-synthetic:
title: 'OSHA chemical data: Graphite (synthetic)'
id: OSHA chemical data page 533, CAS 7440-44-0
url: https://www.osha.gov/chemicaldata/533
year: 2026
kind: database
license: US government work (public domain)
wiki-graphite:
title: 'Wikipedia: Graphite'
id: en.wikipedia.org, Graphite
url: https://en.wikipedia.org/wiki/Graphite
year: 2026
kind: web
license: CC BY-SA 4.0 (cited)
wiki-carbon:
title: 'Wikipedia: Carbon'
id: en.wikipedia.org, Carbon
url: https://en.wikipedia.org/wiki/Carbon
year: 2026
kind: web
license: CC BY-SA 4.0 (cited)
license: CC-BY-4.0
updated: '2026-11-01'
review:
status: draft
method: assistant
checked_values: 15
note: Written by an AI assistant on 2026-11-01 from the Entegris AXF-5Q datasheet, the POCO product page, the 2014 POCO brochure, USGS, OSHA and Wikipedia, all read in this run. Where the datasheet and the brochure both print a value for AXF-5Q, the two agree.
story:
recipe:
line: AXF-5Q is a synthetic graphite made of carbon only. Graphite is a crystalline form of carbon built from stacked graphene layers, and synthetic graphite is made by graphitising hydrocarbon materials at temperatures in excess of 2,100 °C. POCO's brochure says the manufacture of bulk synthetic graphite leaves tiny voids (pores), which are open if they link to the surface and closed if they are isolated.
parts:
- name: Carbon
symbol: C
atoms: 1
atomic_weight: 12.011
role: The only element. The stacked graphene layers set the basic heat and electrical behaviour. AXF-5Q's uniform, isotropic microstructure, as POCO describes it, makes those properties the same in every direction.
risk_groups:
- title: For people
level: 0
verdict: Dust limits apply; no safety data sheet was read
lead: Graphite dust has OSHA and ACGIH exposure limits. No supplier safety data sheet for AXF-5Q was read in this run, so the hazard picture for the grade itself is incomplete.
points:
- label: Dust
line: OSHA's PEL-TWA for graphite (synthetic) is 15 mg/m3 total dust and 5 mg/m3 respirable fraction. The ACGIH TLV-TWA is 2 mg/m3 for respirable particulate matter.
- label: Medical grade
line: The datasheet calls AXF-5Q biocompatible and says it is suitable for implants. These are manufacturer claims; no independent test was read.
- title: In service
level: 1
verdict: Oxidises in air above 450°C
lead: The printed oxidation threshold is 450°C in air, the temperature that gives 1% weight loss in 24 hours. Purifying the graphite raises the threshold by approximately 100°C.
points:
- label: Oxidation
line: The datasheet gives an oxidation threshold of 450°C (840°F) for AXF-5Q in air, defined as 1% weight loss in 24 hours.
- label: Strength
line: The 2014 brochure lists AXF-5Q with the lowest compressive, flexural and tensile strength of the six graphite grades in its table.
why: POCO AXF-5Q is a fine-grain, isotropic synthetic graphite with 5 µm particles and 0.8 µm pores. Its datasheet prints an apparent density of 1.78 g/cm3, a flexural strength of 86 MPa and an oxidation threshold of 450°C in air. The datasheet and product page present the grade for medical implants, not for aerospace or semiconductor parts, so the aerospace claim sometimes made about this grade is not supported by the sources read.
uses:
- where: Mechanical heart valves
line: The datasheet says AXF-5Q is ideal for pyrocarbon-coated substances used by replacement joint and mechanical heart valve manufacturers.
- where: Orthopedic prosthetics and cancer treatments
line: The product page lists orthopedic prosthetics and cancer treatments as applications of AXF-5Q, alongside mechanical heart valves.
can_do:
- label: Dense, fine-grain block
benchmark: density
value: '1.78'
line: AXF-5Q has an apparent density of 1.78 g/cm3 on the datasheet, and the 2014 brochure prints the same value.
- label: Flexural strength
benchmark: flexural_strength
value: '86'
line: AXF-5Q has a flexural strength of 86 MPa, measured by the four-point bend method (datasheet footnote 1).
- label: Heat conduction
benchmark: thermal_conductivity
value: '95'
line: The datasheet prints a thermal conductivity of 95 W/m-K. The 2014 brochure labels this value as estimated.
- label: Thermal limit
benchmark: oxidation_onset_air
value: '450'
line: The oxidation threshold is 450°C in air, defined as 1% weight loss in 24 hours on the datasheet.
compare: AXF-5Q is the base, unimpregnated grade. Among the six graphite grades in POCO's 2014 brochure table, it has the lowest compressive, flexural and tensile strength, the lowest Shore hardness and the highest open porosity. It also has the lowest oxidation threshold of the grades that print one. Its thermal conductivity is the second highest of the six, behind only the impregnated AXF-5QC. The generic structural graphite profile covers isostatic grades from other makers, and the table below compares this grade on three benchmarks.
compare_rows:
- label: Compressive strength
benchmark: compressive_strength
- label: Thermal conductivity
benchmark: thermal_conductivity
- label: Oxidation threshold in air
benchmark: oxidation_onset_air
handling:
- The datasheet prints no handling or storage instructions for AXF-5Q, and no supplier safety data sheet was read.
- Keep parts in air below the 450°C oxidation threshold where they must keep their strength.
- 'Limit dust: keep exposure under OSHA''s PEL-TWA of 5 mg/m3 for the respirable fraction.'
good_for:
- Machinable, fine-grain graphite for medical implant parts; the datasheet names mechanical heart valves, orthopedic prosthetics and cancer treatments.
- Precision parts machined from a dense, uniform block; the datasheet says AXF-5Q is easily machined into precision parts.
watch_out:
- Oxidises in air from 450°C. For hot parts, plan a vacuum or inert atmosphere; no test in those atmospheres was found for AXF-5Q.
- 'Lowest strength of the six POCO graphite grades in the 2014 brochure: 138 MPa compressive, 86 MPa flexural and 62 MPa tensile (the tensile value is an estimate).'
- The biocompatibility and FDA wording come from the manufacturer; no independent test was read.
verdict: AXF-5Q is a fine-grain, isotropic graphite with a printed density of 1.78 g/cm3 and a printed oxidation threshold of 450°C in air. Its sources describe medical implant use and do not support aerospace or semiconductor claims for this grade. Its strength is the lowest of the six POCO graphite grades in the brochure table, so choose it where machinability and the manufacturer's biocompatibility claims matter, not where high strength matters.
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 |
|---|---|---|---|---|
| Entegris AXF-5Q Graphite datasheet | datasheet | 2021 | 19 values | |
| POCO product page: AXF-5Q, industrial graphite grades | web | 2026 | 1 value | |
| POCO Premium Carbon Materials brochure | datasheet | 2014 | 5 values | |
| Mineral Commodity Summaries 2026: Graphite (natural) | report | 2026 | 1 value | |
| About the 2025 List of Critical Minerals (USGS, final list of 60 minerals) | web | 2025 | 0 values | |
| OSHA chemical data: Graphite (synthetic) | database | 2026 | 2 values | |
| Wikipedia: Graphite | web | 2026 | 1 value | |
| Wikipedia: Carbon | web | 2026 | 0 values |