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.