spore: profile
id: ffkm-kalrez
spore_version: 0.2
family: fluoroelastomers
name: Perfluoroelastomer (FFKM, Kalrez)
abbreviation: FFKM
role: Perfluoroelastomer O-ring and seal material for high-temperature and aggressive-chemical service
category: seals-adhesives
type: elastomers-and-o-rings
summary: |
  Kalrez 4079 is a perfluoroelastomer (FFKM) seal material. Qnity Electronics gives its maximum continuous service temperature as 316 °C (600 °F) and its lowest service temperature as -19 °C. DuPont's seal design guide says Kalrez parts are often the elastomer of choice when sealing aggressive chemicals or working at high temperatures. NASA's outgassing compilation lists two other Kalrez O-ring grades, 1050 and 3018, with total mass loss of 0.44% and 0.40% in vacuum.
best_for: Seals that must survive temperatures near 316 °C or aggressive chemicals, where swell and extrusion must stay low (per the Qnity datasheet and DuPont guide)
weakest_at: Low-temperature flexibility (lowest service temperature -19 °C) and compression set that rises from 37% at 204 °C to 45% at 300 °C after 70 hours on O-ring specimens
identity:
  formula: 'Perfluoroelastomer (FFKM): a perfluorinated elastomer with more fluorine than FKM (Wikipedia). The sources read do not print its monomers or cure system.'
  source: dupont-kag-seal-design
  where: Introduction ('Kalrez perfluoroelastomer parts'); Temperature and Thermal Expansion section; FKM and FFKM comparison in the same section
  designations:
    - system: ASTM
      code: FFKM
      note: class designation for perfluoroelastomers, not a grade
      source: dupont-kag-seal-design
      where: Temperature and Thermal Expansion section, note under the temperature chart
    - system: Trade name
      code: Kalrez® 4079
      source: qnity-kalrez-4079
      where: Product page title and grade name (printed with the registered mark)
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - mechanisms
properties:
  - benchmark: max_service_temp
    label: Maximum continuous service temperature, Kalrez 4079
    value: 316
    unit: °C
    scope: material
    conditions:
      grade: Kalrez 4079
      printed: 316 (600) °C (°F)
      test: Qnity proprietary test method
    method: Maximum continuous service temperature stated on the Qnity Kalrez 4079 physical properties table
    status: ground
    source: qnity-kalrez-4079
    where: Physical Properties table, row 'Maximum continuous service temperature'
  - benchmark: min_service_temp
    label: Lowest service temperature, Kalrez 4079
    value: -19
    unit: °C
    scope: material
    conditions:
      grade: Kalrez 4079
      printed: '-19 (-2.2) °C (°F)'
      note: Qnity says performance will vary with seal design and application specifics
    method: Qnity proprietary method, as stated on the physical properties table
    status: ground
    source: qnity-kalrez-4079
    where: Physical Properties table, row 'Lowest Service Temperature'
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at break, Kalrez 4079
    value: 16.88
    unit: MPa
    scope: material
    conditions:
      grade: Kalrez 4079
      specimen: ASTM D412 dumbbell
      printed_psi: '2450'
    method: ASTM D412 tensile test on dumbbell specimens, as reported by Qnity
    status: ground
    source: qnity-kalrez-4079
    where: Physical Properties table, row 'Tensile Strength at Break'
  - benchmark: elongation
    label: Elongation at break, Kalrez 4079
    value: 150
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 4079
      specimen: ASTM D412 dumbbell
    method: ASTM D412 tensile test on dumbbell specimens, as reported by Qnity
    status: ground
    source: qnity-kalrez-4079
    where: Physical Properties table, row 'Elongation at Break'
  - benchmark: modulus_100_percent
    label: 100% modulus, Kalrez 4079
    value: 7.24
    unit: MPa
    scope: material
    conditions:
      grade: Kalrez 4079
      specimen: ASTM D412 dumbbell
      printed_psi: '1050'
    method: ASTM D412 dumbbell test, as reported by Qnity
    status: ground
    note: 'Custom benchmark name: not in the property canon.'
    source: qnity-kalrez-4079
    where: Physical Properties table, row '100% Modulus'
  - benchmark: hardness
    label: Hardness, pellet, Kalrez 4079
    value: 75
    unit: Shore A
    scope: material
    conditions:
      grade: Kalrez 4079
      specimen: pellet
    method: ASTM D2240 on pellet specimens, as reported by Qnity
    status: ground
    source: qnity-kalrez-4079
    where: Physical Properties table, row 'Hardness' (pellet)
  - benchmark: hardness
    label: Hardness, O-ring, Kalrez 4079
    value: 83
    unit: Shore M
    scope: material
    conditions:
      grade: Kalrez 4079
      specimen: AS568 K214 O-ring
    method: ASTM D2240 and ASTM D1414 on O-ring test specimens, as reported by Qnity
    status: ground
    source: qnity-kalrez-4079
    where: Physical Properties table, row 'Hardness' (O-ring)
  - benchmark: compression_set
    label: Compression set, pellet, 70 h at 204 °C
    value: 25
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 4079
      time: 70 hours
      temperature: 204 °C
      specimen: pellet
    method: ASTM D395B on pellet specimens, as reported by Qnity
    status: ground
    note: 'Custom benchmark name: not in the property canon.'
    source: qnity-kalrez-4079
    where: Physical Properties table, row 'Compression Set, 70 hr at 204 °C' (pellet)
  - benchmark: compression_set
    label: Compression set, O-ring, 70 h at 204 °C
    value: 37
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 4079
      time: 70 hours
      temperature: 204 °C
      specimen: AS568 K214 O-ring
    method: ASTM D395B and D1414 on O-ring test specimens, as reported by Qnity
    status: ground
    note: 'Custom benchmark name: not in the property canon.'
    source: qnity-kalrez-4079
    where: Physical Properties table, row 'Compression Set, 70 hr at 204 °C' (O-ring)
  - benchmark: compression_set
    label: Compression set, O-ring, 70 h at 250 °C
    value: 41
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 4079
      time: 70 hours
      temperature: 250 °C
      specimen: AS568 K214 O-ring
    method: ASTM D395B and D1414 on O-ring test specimens, as reported by Qnity
    status: ground
    note: 'Custom benchmark name: not in the property canon.'
    source: qnity-kalrez-4079
    where: Physical Properties table, row 'Compression Set, 70 hr at 250 °C'
  - benchmark: compression_set
    label: Compression set, O-ring, 70 h at 300 °C
    value: 45
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 4079
      time: 70 hours
      temperature: 300 °C
      specimen: AS568 K214 O-ring
    method: ASTM D395B and D1414 on O-ring test specimens, as reported by Qnity
    status: ground
    note: 'Custom benchmark name: not in the property canon.'
    source: qnity-kalrez-4079
    where: Physical Properties table, row 'Compression Set, 70 hr at 300 °C'
  - benchmark: total_mass_loss
    label: Total mass loss in vacuum, Kalrez 1050 O-ring
    value: 0.44
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 1050
      test: 'ASTM E 595 micro-CVCM method: 125 °C for 24 hours in vacuum'
      printed_in_table: 0 44 (decimal point lost in the text layer)
    method: Total mass loss (TML) from the NASA GSFC outgassing table
    status: ground
    note: 'Custom benchmark name: not in the property canon. Values are read from the OCR text layer of a scanned table.'
    source: nasa-rp1124
    where: Section 15 (Rubbers and Elastomers), row 'KALREZ 1050 PERFLUOROELASTOMER', %TML column
  - benchmark: total_mass_loss
    label: Total mass loss in vacuum, Kalrez 3018 O-ring
    value: 0.4
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 3018
      test: 'ASTM E 595 micro-CVCM method: 125 °C for 24 hours in vacuum'
      printed_in_table: 0.40 (printed as 0 40 in the text layer)
    method: Total mass loss (TML) from the NASA GSFC outgassing table
    status: ground
    note: 'Custom benchmark name: not in the property canon. Values are read from the OCR text layer of a scanned table.'
    source: nasa-rp1124
    where: Section 15 (Rubbers and Elastomers), row 'KALREZ 3018 PERFLUOROELASTOMER', %TML column
  - benchmark: cvcm
    label: Collected volatile condensable materials, Kalrez 1050
    value: 0
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 1050
      test: 'ASTM E 595 micro-CVCM method: 125 °C for 24 hours in vacuum'
      printed_in_table: '0.00'
    method: Collected volatile condensable materials (CVCM) from the NASA GSFC outgassing table
    status: ground
    note: 'Custom benchmark name: not in the property canon.'
    source: nasa-rp1124
    where: Section 15 (Rubbers and Elastomers), row 'KALREZ 1050 PERFLUOROELASTOMER', %CVCM column
  - benchmark: cvcm
    label: Collected volatile condensable materials, Kalrez 3018
    value: 0
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 3018
      test: 'ASTM E 595 micro-CVCM method: 125 °C for 24 hours in vacuum'
      printed_in_table: '0.00'
    method: Collected volatile condensable materials (CVCM) from the NASA GSFC outgassing table
    status: ground
    note: 'Custom benchmark name: not in the property canon.'
    source: nasa-rp1124
    where: Section 15 (Rubbers and Elastomers), row 'KALREZ 3018 PERFLUOROELASTOMER', %CVCM column
  - benchmark: water_vapor_regained
    label: Water vapor regained, Kalrez 1050
    value: 0.08
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 1050
      test: 24 hours at 25 °C and 50% relative humidity after the vacuum test
      printed_in_table: '0.08'
    method: Water vapor regained (WVR) from the NASA GSFC outgassing table
    status: ground
    note: 'Custom benchmark name: not in the property canon.'
    source: nasa-rp1124
    where: Section 15 (Rubbers and Elastomers), row 'KALREZ 1050 PERFLUOROELASTOMER', %WVR column
  - benchmark: water_vapor_regained
    label: Water vapor regained, Kalrez 3018
    value: 0.08
    unit: '%'
    scope: material
    conditions:
      grade: Kalrez 3018
      test: 24 hours at 25 °C and 50% relative humidity after the vacuum test
      printed_in_table: '0.08'
    method: Water vapor regained (WVR) from the NASA GSFC outgassing table
    status: ground
    note: 'Custom benchmark name: not in the property canon.'
    source: nasa-rp1124
    where: Section 15 (Rubbers and Elastomers), row 'KALREZ 3018 PERFLUOROELASTOMER', %WVR column
corrosion:
  - environment: Air at 204 to 300 °C for 70 hours (thermal ageing, measured as compression set)
    headline: Compression set rises from 37% at 204 °C to 45% at 300 °C after 70 hours on O-ring specimens.
    effect: Qnity's table gives O-ring compression set of 37% at 204 °C, 41% at 250 °C and 45% at 300 °C after 70 hours. DuPont says higher compression set in perfluoroelastomers comes mainly from stress relaxation rather than thermal or chemical degradation, so Kalrez parts stay soft after long exposure at high temperature.
    rating: moderate
    conditions:
      specimen: AS568 K214 O-ring
      time: 70 hours
      test: ASTM D395B and D1414
    source: qnity-kalrez-4079
    where: Physical Properties table; DuPont guide, O-ring Compression Set section
  - environment: Chemical exposure (general statement, no numeric swell value printed)
    headline: DuPont describes Kalrez as the ultimate in chemical resistance, with minimal swell.
    effect: DuPont says Kalrez perfluoroelastomer parts 'can provide the ultimate in chemical resistance', which means minimal swell and a lower chance of extrusion. It also says exposure testing in the actual chemical is often the only way to get an accurate swell value, and that immersion in fluorinated oils can cause significant swell.
    rating: low
    conditions:
      basis: qualitative statement; no swell percentage printed in the sources read
    source: dupont-kag-seal-design
    where: Chemical Resistance section; Lubrication section
  - environment: Vacuum at 125 °C for 24 hours (NASA outgassing test, ASTM E 595 micro-CVCM method)
    headline: Kalrez 1050 and 3018 O-rings lost 0.44% and 0.40% of their mass in vacuum, with CVCM of 0.00% for both.
    effect: NASA's compilation lists only materials with total mass loss of 1.0% or less and CVCM of 0.10% or less. Both Kalrez O-ring grades in the table fall inside those limits. The table gives no value for Kalrez 4079 itself.
    rating: low
    conditions:
      grade: Kalrez 1050 and 3018
      test: 125 °C for 24 hours in vacuum
      limits_for_listing: TML 1.0% or less and CVCM 0.10% or less
    source: nasa-rp1124
    where: Section C introduction (listing criteria); Section 15 table rows for Kalrez 1050 and 3018
  - environment: High-pressure gas, carbon dioxide at 2000 psi (rapid gas decompression)
    headline: Rapid gas decompression can blister or split a Kalrez O-ring; DuPont suggests Kalrez 0090 for this case.
    effect: DuPont says gas that has dissolved in the seal can expand when system pressure drops suddenly and can blow the O-ring apart. In less severe cases the O-ring may blister or develop small splits. The application guide can select Kalrez 0090 to reduce this problem.
    rating: moderate
    conditions:
      example_fluid: carbon dioxide at 2000 psi
    source: dupont-kag-seal-design
    where: Pressure and Extrusion section, Rapid Gas Decompression paragraph
risks:
  hazards:
    - text: DuPont product literature states that highly toxic products can be generated when Kalrez parts are exposed to fire or to temperatures above 400 °C, so respiratory equipment should be used if ventilation is inadequate.
      ghs: []
      source: dupont-kalrez-tech-2010
      where: Product Safety section
    - text: The KRZ028 family safety data sheet (DuPont Dow Elastomers, 2004) says that above 204 °C small amounts of carbon monoxide and carbon dioxide are given off, and above 400 °C small amounts of hydrogen fluoride and perfluoroolefins are given off.
      ghs: []
      source: kalrez-krz028-msds
      where: Stability and Reactivity, Decomposition
    - text: The KRZ028 family safety data sheet says that inhaling fumes from overheating or burning Kalrez, or from smoking contaminated tobacco, may cause polymer fume fever, a flu-like illness with chills and fever that goes away in 24 to 48 hours.
      ghs: []
      source: kalrez-krz028-msds
      where: Hazards Identification, Inhalation
    - text: The KRZ028 family safety data sheet (2004) says Kalrez perfluoroelastomer is incompatible with or can react with molten alkali metals and interhalogen compounds.
      ghs: []
      source: kalrez-krz028-msds
      where: Stability and Reactivity, Incompatibility with Other Materials
  failure_risks:
    - mode: Breakage during installation
      trigger: Stretching the O-ring by more than 50% of its elongation at break; the guide's example avoids more than 60% stretch for an O-ring with 120% elongation
      consequence: The O-ring can break. For small O-rings the guide suggests keeping installation stretch under 25% of the elongation at break.
      severity: moderate
      source: dupont-kag-seal-design
      where: Stretch section
    - mode: Splitting from over-compression
      trigger: Relative compression of 30% or greater, which can happen when parts heat up
      consequence: Parts can split or crack, then fail. The guide suggests 14% to 18% compression for static seals.
      severity: high
      source: dupont-kag-seal-design
      where: Compression section
    - mode: Premature failure from assembled stretch
      trigger: Assembled stretch greater than 5% on the inner-diameter seal
      consequence: High internal stress and premature failure. The guide suggests 1% to 3% assembled stretch when sealing on the inner diameter.
      severity: moderate
      source: dupont-kag-seal-design
      where: Stretch section, assembled stretch paragraph
    - mode: Leak after cooling (compression set)
      trigger: Long continuous use at high temperature followed by cooling
      consequence: The seal keeps its high-temperature shape and can leak as it contracts. The guide says to let it recover by raising the temperature before applying fluid pressure, or to replace it.
      severity: moderate
      source: dupont-kag-seal-design
      where: O-ring Compression Set section
    - mode: Extrusion at high temperature and pressure
      trigger: High temperature, where Kalrez softens and loses modulus, combined with high pressure and a wide clearance gap
      consequence: The seal extrudes into the gap and can fail. The guide suggests keeping the clearance gap to 0.002 to 0.005 in (0.051 to 0.127 mm) and using anti-extrusion rings at high pressure.
      severity: moderate
      source: dupont-kag-seal-design
      where: O-ring Extrusion Due to High Pressure section
  side_effects:
    - text: Kalrez parts soften at high temperature and lose some mechanical properties, which can aggravate extrusion.
      affects: Seal gland and clearance gap
      source: dupont-kag-seal-design
      where: O-ring Extrusion Due to High Pressure section
    - text: The linear coefficient of thermal expansion for Kalrez parts can be in the range of 50% greater than a fluoroelastomer of similar hardness, so the gland volume must be checked when a lower-temperature seal is replaced.
      affects: Gland groove volume
      source: dupont-kag-seal-design
      where: Temperature and Thermal Expansion section
    - text: Immersing a perfluoroelastomer in fluorinated oil can cause significant swell. A thin film of fluorinated oil applied for installation does not affect performance.
      affects: Seal dimensions
      source: dupont-kag-seal-design
      where: Lubrication section
  handling:
    - text: Apply a light lubricant film during installation. The guide names fluorinated oil, powdered graphite or water as examples, and the lubricant must not swell or degrade the O-ring.
      source: dupont-kag-seal-design
      where: Lubrication section
    - text: Use a gland sealing surface finish of 32 µinch for most applications, and 16 µinch or better when sealing gases or in vacuum.
      source: dupont-kag-seal-design
      where: Surface Roughness section
    - text: For small O-rings, stretch evenly with a special tool such as a cone device. A high localized elongation can break the O-ring.
      source: dupont-kag-seal-design
      where: Stretch section
  mitigations:
    - text: Use anti-extrusion (backup) rings for high-pressure applications and keep the clearance gap at the minimum achievable, typically 0.002 to 0.005 in (0.051 to 0.127 mm).
      source: dupont-kag-seal-design
      where: Pressure and Extrusion section
    - text: Use 0% stretch for an O-ring that seals against a rotating shaft, because stretch causes heat build-up (the Gough-Joule effect).
      source: dupont-kag-seal-design
      where: Stretch section
uses:
  - application: mechanisms
    device: O-ring seal in spacecraft hardware (NASA outgassing compilation for spacecraft materials)
    example: NASA Reference Publication 1124 lists Kalrez 1050 and Kalrez 3018 as O-rings in its Rubbers and Elastomers section, among materials screened for spacecraft use.
    source: nasa-rp1124
    where: Section 15 (Rubbers and Elastomers), rows for KALREZ 1050 and KALREZ 3018, application column
  - application: mechanisms
    device: Seal for aggressive chemicals or high temperature
    example: DuPont says that when sealing aggressive chemicals or at high temperatures, Kalrez perfluoroelastomer parts are often the elastomer of choice.
    source: dupont-kag-seal-design
    where: Introduction section
supply:
  - subject: Fluorspar (fluorine feedstock)
    abundance: Not stated for fluorspar in the source read
    producers:
      - country: China
        share_percent: 60
        year: 2025
      - country: Mexico
        share_percent: 15
        year: 2025
      - country: Mongolia
        share_percent: 15
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals (fluorspar listed)
        listed: true
    recycling: 'USGS: synthetic fluorspar may be produced from waste neutralization in uranium enrichment, petroleum alkylation and stainless-steel pickling, but undesirable impurities constrain its use.'
    substitutes:
      - 'USGS: fluorosilicic acid has been used as an alternative to fluorspar in producing AlF3 and HF.'
    source: usgs-mcs2026-fluorspar
    where: World Mine Production and Reserves table, 2025 column (world total 10,000 thousand t, rounded; shares calculated by Space Mushroom from China 6,000, Mexico 1,500 and Mongolia 1,500 thousand t); Recycling; Substitutes. The USGS text says aqueous HF is the primary feedstock for fluorine-bearing chemicals, including fluoropolymers.
media: []
documents:
  - title: Kalrez 4079 product page, Qnity Electronics (physical properties)
    type: datasheet
    url: https://www.qnityelectronics.com/products/kalrez-4079.html
    year: 2026
  - title: Seal Design Considerations for Kalrez and Utilizing the Kalrez Application Guide (DuPont)
    type: datasheet
    url: https://www.dupont.com/KAG/pdf/SealDesignConsiderationsUsingKalrez.pdf
  - title: 'NASA Reference Publication 1124, Rev. 3: Outgassing Data for Selecting Spacecraft Materials'
    type: report
    url: https://ntrs.nasa.gov/api/citations/19940017416/downloads/19940017416.pdf
    year: 1993
  - title: Mineral Commodity Summaries 2026, Fluorspar
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf
    year: 2026
  - title: Material Safety Data Sheet KRZ028, Kalrez perfluoroelastomer compounds (DuPont Dow Elastomers, revised 14 May 2004; copy hosted by ERIKS)
    type: sds
    url: https://o-ring.info/en/datasheets/kalrez/ERIKS%20-%20MSDS%20-%20KRZ028.pdf
    year: 2004
  - title: Kalrez Spectrum and Kalrez Physical Properties and Product Comparisons, Technical Information Rev. 8 (DuPont Performance Elastomers, January 2010; copy hosted by Jefferson Lab)
    type: datasheet
    url: https://hallaweb.jlab.org/tech/Detectors/public_html/manuals/data_sheets-manuals/D-F/D/dupont/kalrez.pdf
    year: 2010
gaps:
  - Propellant, oxidiser and semiconductor-vacuum seal uses were not found in any page fetched in this run (the web search budget ran out), so they are not stated as uses.
  - No PubChem GHS record for the perfluoroelastomer class was found in a search. The hazards come from DuPont's 2004 family safety data sheet (KRZ028, covering all Kalrez compounds, not a Kalrez 4079 sheet) and the 2010 DuPont technical sheet. The Qnity safety data sheet for Kalrez 4079 opens a sign-in page and was not read. The family sheet prints no GHS hazard statements.
  - 'Composition is not disclosed: the monomers and cure system are not printed in the Qnity or DuPont sources read. Wikipedia gives only a general description (more fluorine than FKM).'
  - No density, glass transition, or dynamic temperature range was found as text. The DuPont temperature range chart and thermal expansion charts are images with no printed values.
  - Chemical swell and retained-sealing-force numbers (Lucas test) are shown only in graphs with no printed values in the text.
  - Wikipedia gives a maximum continuous service temperature of 327 °C for certain FFKM grades. It is not used as a value here because it is not the Kalrez 4079 datasheet value.
  - The NASA table values for Kalrez 1050 and 3018 are read from the OCR text layer of a scanned table. Decimal points appear lost in some cells, and the values are not Kalrez 4079 values.
  - Hardness, compression set, total mass loss, CVCM, water vapor regained and 100% modulus are custom benchmark names because no canonical name fits.
  - Producers of perfluoroelastomer itself and their country shares were not found. The fluorspar shares are a feedstock proxy, not perfluoroelastomer supply.
  - EU critical raw materials status for fluorspar was not checked.
  - The oil and gas exploration and production use named by Qnity has no matching application slug in the brief, so it is described in the story but not listed under uses.
  - No images were fetched with a usable licence, so media is empty.
  - The Qnity page was read through a summarising fetch, not a raw copy of the page.
sources:
  qnity-kalrez-4079:
    title: Kalrez 4079, Qnity Electronics product page (physical properties table)
    id: Qnity Electronics, Kalrez 4079
    url: https://www.qnityelectronics.com/products/kalrez-4079.html
    year: 2026
    kind: datasheet
    license: supplier web page, linked not reproduced
  dupont-kag-seal-design:
    title: Seal Design Considerations for Kalrez and Utilizing the Kalrez Application Guide
    id: DuPont Kalrez application guide (PDF)
    url: https://www.dupont.com/KAG/pdf/SealDesignConsiderationsUsingKalrez.pdf
    kind: datasheet
    license: supplier document, linked not reproduced
  nasa-rp1124:
    title: Outgassing Data for Selecting Spacecraft Materials, NASA Reference Publication 1124, Revision 3
    id: NTRS 19940017416; Campbell and Scialdone, Goddard Space Flight Center, September 1993
    url: https://ntrs.nasa.gov/api/citations/19940017416/downloads/19940017416.pdf
    year: 1993
    kind: report
    license: public domain (NASA)
  usgs-mcs2026-fluorspar:
    title: Mineral Commodity Summaries 2026, Fluorspar
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-fluorspar.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-crit2025:
    title: About the 2025 List of Critical Minerals (USGS)
    id: USGS 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: public domain (USGS)
  wikipedia-kalrez:
    title: Kalrez, Wikipedia (composition and curing description only)
    id: en.wikipedia.org/wiki/Kalrez
    url: https://en.wikipedia.org/wiki/Kalrez
    kind: web
    license: CC BY-SA 4.0 (Wikipedia)
  kalrez-krz028-msds:
    title: Material Safety Data Sheet KRZ028, Kalrez perfluoroelastomer compounds (all compounds in the synonym list)
    id: DuPont Dow Elastomers L. L. C., KRZ028, revised 14-MAY-2004
    url: https://o-ring.info/en/datasheets/kalrez/ERIKS%20-%20MSDS%20-%20KRZ028.pdf
    year: 2004
    kind: datasheet
    license: supplier document, linked not reproduced
  dupont-kalrez-tech-2010:
    title: Kalrez Spectrum and Kalrez Physical Properties and Product Comparisons, Technical Information Rev. 8
    id: DuPont Performance Elastomers, Rev. 8, January 2010
    url: https://hallaweb.jlab.org/tech/Detectors/public_html/manuals/data_sheets-manuals/D-F/D/dupont/kalrez.pdf
    year: 2010
    kind: datasheet
    license: supplier document, linked not reproduced
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 17
  unreachable: 1
  caveats: 3
  note: 'Written by an AI assistant on 2026-11-01 from the Qnity Kalrez 4079 page, the DuPont Kalrez application guide, NASA RP 1124 Rev. 3 (outgassing table), the USGS fluorspar summary, the USGS 2025 critical minerals list, DuPont''s 2004 Kalrez family safety data sheet (KRZ028) and DuPont''s 2010 Kalrez technical sheet. Not verified: the Kalrez 4079 safety data sheet (sign-in page), the propellant and semiconductor uses, and the OCR-read NASA values.'
story:
  recipe:
    line: Perfluoroelastomer (FFKM) is a perfluorinated elastomer. The sources read do not print its monomers, cure system or atomic formula, so no composition or atomic share is stated here. Kalrez is the brand name of the grade family, and Kalrez 4079 is the grade on the Qnity datasheet.
    parts: []
  risk_groups:
    - title: For people
      lead: DuPont's 2004 safety data sheet for all Kalrez perfluoroelastomer compounds and its 2010 technical sheet both warn about fire and heat. No GHS hazard statement is printed for Kalrez 4079 in either.
      points:
        - label: Safety data sheet
          line: The Qnity safety data sheet for Kalrez 4079 opens a sign-in page, so the family sheet from DuPont is the one read. Check the current sheet for the grade you buy before handling.
        - label: Fumes and decomposition
          line: Above 400 °C Kalrez gives off small amounts of hydrogen fluoride and perfluoroolefins, and fumes from overheating can cause polymer fume fever. Heating above the 316 °C service limit is outside the datasheet and should be avoided.
    - title: If a seal fails
      lead: These risks come from the DuPont design guide and the NASA test data, not from incident reports.
      points:
        - label: Over-stretch on installation
          line: Stretching an O-ring by more than 50% of its elongation at break can break it. DuPont's example avoids more than 60% stretch for an O-ring with 120% elongation.
        - label: Over-compression
          line: Relative compression of 30% or more can split or crack a Kalrez O-ring. The guide suggests 14% to 18% compression for static seals.
        - label: High pressure and gas
          line: At high temperature Kalrez softens and can extrude into the gap under pressure. With carbon dioxide at 2000 psi, a rapid pressure drop can blister or split the O-ring.
    - title: Handling
      points:
        - label: Lubricant
          line: Use a light film of lubricant on the O-ring. Fluorinated oil can cause significant swell if the O-ring is immersed in it.
        - label: Surface finish
          line: Use a gland surface finish of 32 µinch in most cases, and 16 µinch or better for gas or vacuum sealing.
  why: Kalrez 4079 is a perfluoroelastomer, abbreviated FFKM, sold as a seal material. Qnity Electronics gives its maximum continuous service temperature as 316 °C. DuPont's seal design guide says Kalrez parts are often the elastomer of choice where aggressive chemicals or high temperatures are involved, because they can be the only elastomers stable at those temperatures.
  uses:
    - where: Spacecraft hardware
      line: NASA Reference Publication 1124 lists Kalrez 1050 and Kalrez 3018 O-rings in its table of materials screened for spacecraft use. Both show total mass loss in vacuum of 0.44% and 0.40%, with CVCM of 0.00%.
    - where: Aggressive chemicals and high temperature
      line: DuPont says Kalrez perfluoroelastomer parts are often the elastomer of choice when sealing aggressive chemicals or at high temperatures.
    - where: Oil and gas exploration and production
      line: Qnity lists exploration and production services as the application for Kalrez 4079 and calls the parts best in class for chemical resistance. This is the only application Qnity names on the page.
  can_do:
    - label: Temperature
      benchmark: max_service_temp
      value: 316 °C
      line: Kalrez 4079 is rated for a maximum continuous service temperature of 316 °C. Its lowest service temperature is -19 °C, and Qnity notes that performance varies with seal design and application.
    - label: Chemical resistance
      line: DuPont says Kalrez can provide the ultimate in chemical resistance, with minimal swell. It also says exposure testing in the real chemical is often the only reliable way to measure swell.
    - label: Vacuum
      benchmark: total_mass_loss
      value: 0.44%
      line: In NASA's vacuum test at 125 °C for 24 hours, Kalrez 1050 lost 0.44% of its mass and Kalrez 3018 lost 0.40%. Both grades show CVCM of 0.00%. These are grade values, not Kalrez 4079 values.
    - label: Compression set
      benchmark: compression_set
      value: 37% at 204 °C
      line: After 70 hours at 204 °C, a Kalrez 4079 O-ring had 37% compression set. The value rose to 41% at 250 °C and 45% at 300 °C.
    - label: Strength
      benchmark: ultimate_tensile_strength
      value: 16.88 MPa
      line: Tensile strength at break is 16.88 MPa (2450 psi), with elongation at break of 150%, both by ASTM D412 on dumbbell specimens.
  compare: Kalrez 4079 is a perfluoroelastomer seal material. DuPont says its linear coefficient of thermal expansion can be in the range of 50% greater than a fluoroelastomer of similar hardness, so the gland volume has to be checked when a lower-temperature seal is replaced by Kalrez. The table compares its service temperature limits and the vacuum mass loss measured for the grades in the NASA table.
  compare_rows:
    - label: Maximum continuous service temperature
      benchmark: max_service_temp
    - label: Lowest service temperature
      benchmark: min_service_temp
    - label: Total mass loss in vacuum (grade 1050)
      benchmark: total_mass_loss
  handling:
    - Keep installation stretch under 50% of the elongation at break, and under 25% for small O-rings.
    - Keep compression between 14% and 18% for static seals. 30% or more can split the part.
    - Use a light film of lubricant. Do not immerse the O-ring in fluorinated oil, which can cause significant swell.
    - Keep the material away from molten alkali metals and interhalogen compounds, which the 2004 safety data sheet lists as incompatible. Check the current supplier safety data sheet for the grade before handling.
  good_for:
    - High-temperature seals. Qnity gives a maximum continuous service temperature of 316 °C for Kalrez 4079.
    - Aggressive chemicals. DuPont calls the chemical resistance the ultimate, with minimal swell.
    - Vacuum screening. NASA's table lists two Kalrez O-ring grades with low total mass loss.
  watch_out:
    - Low-temperature limit. The lowest service temperature is -19 °C, and low-temperature or vacuum sealing may need a special gland design.
    - Thermal cycling. A seal can leak after cooling because of compression set. Recover it by reheating before pressure is applied, or replace it.
    - Grade values. The NASA outgassing values belong to Kalrez 1050 and 3018, not to Kalrez 4079.
  verdict: Kalrez 4079 suits seals that must survive heat near 316 °C and aggressive chemicals, within the datasheet and design-guide limits. Its hazards come from DuPont's family safety data sheet and technical sheet, not from a 4079 sheet, and the propellant and semiconductor uses were not verified.