spore: profile
id: tin-antimony-babbitt
spore_version: 0.2
family: low-melting-metals-and-solders
name: Tin-antimony babbitt (tin-base bearing metal)
abbreviation: Sn-Sb-Cu
role: soft bearing-lining alloy
category: metals
type: heavy-metals
summary: |
  Tin-base babbitt is a soft alloy of tin with about 7.5% antimony and 3.5% copper (ASTM B23 Grade 2, nominal 89% tin). It is used as a thin running surface in plain bearings. The ASTM B23 Grade 2 grade has a density of 7.39 g/cm3, a solidus of 241 degC and a liquidus of 354 degC, a Brinell hardness of 24.5, and a chill-cast tensile strength of 77.0 MPa, according to the Kapp Alloy datasheet. Its elongation differs between two datasheets (18% on Kapp, 8.0% on Trotter), and the sheets give no test conditions for the Trotter figure.
best_for: 'Thin plain-bearing linings that must tolerate repeated loading: Wikipedia says combustion engines use tin-based babbitt because it withstands cyclic loading'
weakest_at: 'Strength and temperature: a solidus of 241 degC, a Brinell hardness of 24.5 and 42.1 MPa compressive yield. Tin pest and antimony toxicity add cold and handling limits.'
identity:
  formula: 'Tin-base babbitt ASTM B23 Grade 2: Sn 89, Sb 7.5, Cu 3.5 nominal (mass %), limits Sn 88 to 90, Sb 7 to 8, Cu 3 to 4, Pb up to 0.35. Lead-based babbitt BS 3332 Alloy G: Pb balance, Sn 4.5 to 6.5, Sb 14 to 17 (mass %). Pewter: tin 85 to 99, antimony about 5 to 10, copper about 2 (mass %); typical European casting pewter Sn 94, Cu 1, Sb 5.'
  source: kapp-grade2
  where: Chemical composition limits on the Kapp Alloy product page and the Nathan Trotter datasheet (Sn 89 / Sb 7.5 / Cu 3.5, Pb below 0.35); Wikipedia Babbitt metal (BS 3332 Alloy G) and Wikipedia Pewter (composition paragraphs)
  designations:
    - system: ASTM
      code: B23
      note: Grade 2 tin-base babbitt (the Trotter sheet lists it as ASTM B23-00 Alloy 2)
      source: kapp-grade2
      where: 'Page title ASTM-B23 Grade 2 Tin Babbitt and specification section ASTM B23: Grade 2'
tags:
  applications:
    - mechanisms
    - electronics-and-chips
    - batteries
properties:
  - benchmark: density
    label: Density of tin-base babbitt, ASTM B23 Grade 2
    value: 7.39
    unit: g/cm3
    scope: material
    conditions:
      composition: ASTM B23 Grade 2, nominal Sn 89 / Sb 7.5 / Cu 3.5 (mass %)
      temperature: not stated
    method: Value printed on the Kapp Alloy product page. The same page also prints the unit as mg/m3 once, which is a misprint.
    status: ground
    source: kapp-grade2
    where: Physical properties, density row (7.39 g/cc, 0.267 lb/in3)
  - benchmark: melting_point
    label: Solidus to liquidus range, tin-base babbitt
    value: 241
    value_high: 354
    bound: range
    unit: degC
    scope: material
    conditions:
      basis: printed as 466-669 degF (241-354 degC)
      composition: ASTM B23 Grade 2
    method: Range printed on the Kapp Alloy product page; the Trotter datasheet prints the same 466 and 669 degF as solidus and liquidus.
    status: ground
    source: kapp-grade2
    where: Physical properties, melting range line (466-669 degF (241-354 degC))
  - benchmark: brinell_hardness
    label: Brinell hardness, tin-base babbitt
    value: 24.5
    unit: HB
    scope: material
    conditions:
      ball: 10 mm
      load: 500 kg
      time: 30 s
      composition: ASTM B23 Grade 2
    method: Value printed on the Kapp Alloy product page with its test conditions
    status: ground
    note: The name brinell_hardness is not in spores/property-canon.yaml and is used as it is.
    source: kapp-grade2
    where: Hardness row (24.5, 10 mm ball / 500 kg load - 30 sec)
  - benchmark: ultimate_tensile_strength
    label: Ultimate tensile strength, chill cast at 20 degC
    value: 77
    unit: MPa
    scope: material
    conditions:
      casting: chill cast
      temperature: 20 degC (68 degF)
      composition: ASTM B23 Grade 2
    method: Value in the chill-cast table of the Kapp Alloy product page
    status: ground
    source: kapp-grade2
    where: Tensile table, chill cast row at 20 degC (77.0 MPa, 11,200 psi)
  - benchmark: ultimate_tensile_strength
    label: Ultimate tensile strength, die cast
    value: 87
    unit: MPa
    scope: material
    conditions:
      casting: die cast, poured at 600 degF (315 degC) into a 302 degF (150 degC) mold
      composition: ASTM B23 Grade 2
    method: Value printed on the Kapp Alloy product page, footnote and die-cast entry
    status: ground
    source: kapp-grade2
    where: Tensile entry labelled Diecast (87.0 MPa, 12,600 psi)
  - benchmark: elongation
    label: Elongation at break, chill cast (Kapp)
    value: 18
    unit: '%'
    scope: material
    conditions:
      casting: chill cast
      temperature: 20 degC
      gage: 4 x (area)^1/2 gage length
    method: Value printed on the Kapp Alloy product page, chill-cast entry
    status: ground
    source: kapp-grade2
    where: Elongation entry, chill cast (18% at break)
  - benchmark: elongation
    label: Elongation, ASTM B23 Grade 2 datasheet (Trotter)
    value: 8
    unit: '%'
    scope: material
    conditions:
      basis: product data sheet, no test condition printed
      composition: ASTM B23 Grade 2
    method: Value printed on the Nathan Trotter Grade 2 datasheet. It is lower than the chill-cast figure from Kapp, and the two sheets do not give matching test conditions.
    status: ground
    source: trotter-grade2
    where: Physical properties, Elongation % row (8.0)
  - benchmark: elastic_modulus
    label: Tensile elastic modulus, cast tin-base babbitt
    value: 52
    unit: GPa
    scope: material
    conditions:
      test: tension
      casting: cast at 400 degC into a 100 degC mold
    method: Value in the mechanical properties table of the Kapp Alloy product page
    status: ground
    source: kapp-grade2
    where: Elastic modulus row (52 GPa)
  - benchmark: fatigue_strength
    label: Fatigue strength, chill cast tin-base babbitt
    value: 33
    unit: MPa
    scope: material
    conditions:
      test: R.R. Moore
      cycles: 2 x 10^7 (printed as 2 x 107)
      casting: chill cast
    method: Value printed on the Kapp Alloy product page, fatigue entry
    status: ground
    source: kapp-grade2
    where: Fatigue entry, R.R. Moore test (33.0 MPa, 4790 psi)
  - benchmark: compressive_yield_strength
    label: Compressive yield strength, tin-base babbitt
    value: 42.1
    unit: MPa
    scope: material
    conditions:
      set: 0.125% set
      composition: ASTM B23 Grade 2
    method: Value printed on the Kapp Alloy product page, compressive entry
    status: ground
    note: The name compressive_yield_strength is not in spores/property-canon.yaml and is used as it is.
    source: kapp-grade2
    where: Compressive entry (42.1 MPa at 0.125% set)
  - benchmark: melting_point
    label: Melting point of pure tin, for comparison with the babbitt
    value: 231.9
    unit: degC
    scope: material
    conditions:
      form: pure tin
      pressure: not stated
    method: Value listed in the melting point section of the PubChem record for tin
    status: ground
    source: pubchem-tin
    where: Experimental Properties, melting point entries (231.9 degC)
  - benchmark: allotropic_transformation_temperature
    label: Tin pest transition, white tin to grey tin
    value: 13.2
    unit: degC
    scope: material
    conditions:
      transformation: white (beta) tin to grey (alpha) tin, at and below the temperature
      basis: pure tin; the babbitt alloy is not tested
    method: Value printed in the allotropic transformation section of Wikipedia Tin pest
    status: ground
    note: The name allotropic_transformation_temperature is not in spores/property-canon.yaml and is used as it is.
    source: wiki-tin-pest
    where: Allotropic transformation section, At 13.2 degC (55.8 degF) and below
  - benchmark: volume_change
    label: Volume increase, white tin to grey tin
    value: 27
    unit: '%'
    scope: material
    conditions:
      basis: change from white (beta) to grey (alpha) tin
      composition: pure tin
    method: Value printed in the allotropic transformation section of Wikipedia Tin pest
    status: ground
    source: wiki-tin-pest
    where: Allotropic transformation section, a large volume increase of about 27%
  - benchmark: melting_point
    label: Melting point of antimony metal, the alloying element
    value: 630
    unit: degC
    scope: material
    conditions:
      form: antimony metal
      pressure: not stated
    method: Value listed in the melting point section of the PubChem record for antimony
    status: ground
    source: pubchem-antimony
    where: Experimental Properties, melting point entries (630 degC)
  - benchmark: density
    label: Density of antimony metal, the alloying element
    value: 6.68
    unit: g/cm3
    scope: material
    conditions:
      temperature: 20 degC
      form: antimony metal
    method: Value printed in the density section of the PubChem record for antimony
    status: ground
    source: pubchem-antimony
    where: Experimental Properties, density entries (6.68 g/cu cm at 20 degC)
corrosion:
  - environment: Below 13.2 degC, pure tin
    headline: At and below 13.2 degC, white tin can change to grey tin with a volume increase of about 27%.
    effect: Wikipedia gives 13.2 degC as the temperature at and below which the change happens. It says the change is slow to start because of a high activation energy and then speeds up, and it gives a volume increase of about 27%. No rate test on the babbitt alloy was found.
    rating: moderate
    conditions:
      basis: pure tin; alloy behaviour not stated in the source
      condition: temperature at or below 13.2 degC
    source: wiki-tin-pest
    where: Allotropic transformation section
risks:
  hazards:
    - text: 'PubChem notifications for antimony metal (CID 5354495): H301 (18.2%) toxic if swallowed, H302 (23.4%) harmful if swallowed, H332 (26.9%) harmful if inhaled, H351 (31.8%) suspected of causing cancer. Signal word Danger. 18.7% (140 of 748) of company reports say antimony does not meet GHS criteria.'
      ghs:
        - H301
        - H302
        - H332
        - H351
      source: pubchem-antimony
      where: GHS Classification section, aggregated ECHA notifications (CID 5354495)
    - text: 'PubChem notifications for lead (CID 5352425): H360 (84.4%) may damage fertility or the unborn child, H372 (50.5%) causes damage to organs through prolonged or repeated exposure. Signal word Danger.'
      ghs:
        - H360
        - H372
      source: pubchem-lead
      where: GHS Classification section, aggregated ECHA notifications (CID 5352425)
    - text: 'PubChem notifications for tin (CID 5352426): 72.9% (695 of 953) of company reports say tin does not meet GHS criteria. Where codes were given, H319 (24.2%) causes serious eye irritation and H335 (23.1%) may cause respiratory irritation. Signal word Warning. One further notification gives H372, damage to organs through prolonged or repeated exposure.'
      ghs:
        - H319
        - H335
        - H372
      source: pubchem-tin
      where: GHS Classification section, ECHA and NITE-CMC notifications (CID 5352426)
  failure_risks:
    - mode: Overheating of the bearing lining
      trigger: Operating temperature rises to the solidus of 241 degC
      consequence: The Kapp datasheet gives a solidus of 241 degC and a liquidus of 354 degC. Above the solidus the alloy starts to melt, so the lining loses its strength before it reaches the liquidus. No failure test was read for this grade.
      severity: high
      source: kapp-grade2
      where: Physical properties, melting range line
    - mode: Tin pest, transformation to grey tin
      trigger: Exposure to temperatures at or below 13.2 degC
      consequence: Wikipedia gives a volume increase of about 27% for the change to grey tin. The source gives no rate for the babbitt alloy, and the alloy is not tested for this change.
      severity: moderate
      source: wiki-tin-pest
      where: Allotropic transformation section
  side_effects: []
  handling:
    - text: The PubChem hazard codes above (H319, H335 and H372 for tin; H301, H302, H332 and H351 for antimony; H360 and H372 for lead) are for the elements, not for a babbitt grade. The sources read give no handling advice for the alloy; check the supplier's safety data sheet for the grade you buy.
      source: pubchem-antimony
      where: GHS Classification sections, CID 5354495, 5352425 and 5352426
  mitigations: []
uses:
  - application: mechanisms
    device: Engine plain bearings (tin-based babbitt)
    example: 'Wikipedia: internal combustion engines use Babbitt metal which is primarily tin-based because it can withstand cyclic loading. Poured Babbitt bearings were common in automotive applications until the mid-1950s.'
    source: wiki-babbitt
    where: Lead introduction and Design, Modern section
  - application: mechanisms
    device: Bearing metals, bronze and brass (babbitt, tinning)
    example: 'USGS: babbitt, brass and bronze, and tinning together took 7% of tin use in the United States in 2025.'
    source: usgs-mcs2026-tin
    where: Domestic Production and Use paragraph (uses percentages)
  - application: electronics-and-chips
    device: Solder
    example: 'USGS: solder took 11% of tin use in the United States in 2025.'
    source: usgs-mcs2026-tin
    where: Domestic Production and Use paragraph (uses percentages)
  - application: batteries
    device: Antimonial lead for lead-acid battery plates (antimony context)
    example: 'USGS: secondary antimony was intended for the lead-acid battery industry, and antimonial lead and ammunition took 40% of antimony use in the United States in 2025.'
    source: usgs-mcs2026-antimony
    where: Domestic Production and Use paragraph
supply:
  - subject: Tin (mine production)
    producers:
      - country: China
        share_percent: 24.5
        year: 2025
      - country: Indonesia
        share_percent: 21
        year: 2025
      - country: Peru
        share_percent: 11.4
        year: 2025
      - country: Brazil
        share_percent: 9.7
        year: 2025
      - country: Congo (Kinshasa)
        share_percent: 9.3
        year: 2025
    recycling: 'USGS: about 17,000 tons of tin from old and new scrap was recycled in 2025, accounting for 22% of apparent consumption.'
    substitutes:
      - 'USGS: plastics for bearing metals that contain tin; epoxy resins for solder; alternative copper-base alloys for bronze.'
    source: usgs-mcs2026-tin
    where: World Mine Production and Reserves table, 2025e column (world total 290,000 t; shares calculated by Space Mushroom from China 71,000, Indonesia 61,000, Peru 33,000, Brazil 28,000 and Congo (Kinshasa) 27,000 over the world total); Recycling; Substitutes
  - subject: Antimony (mine production)
    producers:
      - country: China
        share_percent: 36.4
        year: 2025
      - country: Russia
        share_percent: 29.1
        year: 2025
      - country: Tajikistan
        share_percent: 20
        year: 2025
      - country: Bolivia
        share_percent: 4.5
        year: 2025
      - country: Australia
        share_percent: 1.2
        year: 2025
    recycling: 'USGS: recycling supplied 12% of estimated domestic apparent consumption in 2025.'
    substitutes:
      - 'USGS: combinations of calcium, copper, selenium, sulfur, and tin are substitutes for alloys in lead-acid batteries.'
    source: usgs-mcs2026-antimony
    where: World Mine Production and Reserves table, 2025e column (world total 110,000 t; shares calculated by Space Mushroom from China 40,000, Russia 32,000, Tajikistan 22,000, Bolivia 5,000 and Australia 1,300 over the world total); Recycling; Substitutes
media: []
documents:
  - title: 'Nathan Trotter & Co. product data sheet: ASTM Grade 2 Babbitt Metal (Rev. 3, 2015)'
    type: datasheet
    url: https://nathantrotter.com/wp-content/uploads/2020/09/Grade-2-Babbitt-Data.pdf
    year: 2015
  - title: 'Kapp Alloy: DuraKapp 2, ASTM B23 Grade 2 Tin Babbitt'
    type: datasheet
    url: https://www.kappalloy.com/babbitt-alloy/tin-babbitt-alloys/durakapp-2/
  - title: 'USGS Mineral Commodity Summaries 2026: Antimony'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-antimony.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Tin'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tin.pdf
    year: 2026
  - title: 'PubChem compound record: Antimony (CID 5354495), GHS classification and experimental properties'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5354495/JSON
    year: 2026
  - title: 'PubChem compound record: Lead (CID 5352425), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5352425/JSON
    year: 2026
  - title: 'PubChem compound record: Tin (CID 5352426), experimental properties and GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5352426/JSON
    year: 2026
gaps:
  - No standard text (ASTM B23 or BS 3332) was opened; the composition and property values come from vendor and distributor datasheets, not from the standards themselves.
  - Elongation disagrees between the two datasheets (18% chill cast on Kapp, 8.0% on Trotter) and neither gives a full test set; both are recorded.
  - The Kapp page prints the lead limit as 0.1000% in one list and 0.35% in the component table; the Trotter sheet prints below 0.35%. Only the 0.35% limit is used.
  - Lead-based babbitt (BS 3332 Alloy G) is recorded for composition only. No property, corrosion or hazard value for a Sn-Pb-Sb babbitt was read in this run.
  - 'Bismuth-tin alloys were not covered: no source for them was read in this run, so no value is given.'
  - Pewter composition is recorded from Wikipedia (general ranges). The Britannia metal composition was not printed on the page read, and no pewter property value was read.
  - No corrosion test, ageing data or service-environment result was found for tin-antimony babbitt (oil, humidity, fuel or seawater).
  - Tin whisker growth on tin-rich alloys was not read in this run (see the tin profile for the NASA source).
  - No space-environment data (outgassing, vacuum, radiation, atomic oxygen, thermal cycling) was found for any tin-antimony alloy. No flight use of babbitt was found.
  - Antimony critical-mineral status is not stated in the USGS MCS 2026 antimony text read here, and the USGS 2025 critical list was not opened, so critical_lists is left out.
  - Brinell hardness on the Trotter sheet is printed as 24.5/12 with no test conditions, so only the Kapp row (10 mm ball, 500 kg, 30 s) is used.
  - The Sn-Sb binary phase diagram and a thermal conductivity value for the babbitt grade were not found in a fetched source.
  - UNS, EN and JIS designations for tin-base babbitt were not printed on any fetched page, so only the ASTM B23 Grade 2 designation is listed.
sources:
  kapp-grade2:
    title: 'Kapp Alloy: DuraKapp 2, ASTM B23 Grade 2 Tin Babbitt (product page with physical and mechanical data)'
    url: https://www.kappalloy.com/babbitt-alloy/tin-babbitt-alloys/durakapp-2/
    kind: datasheet
    license: vendor product page, cited not reproduced
  trotter-grade2:
    title: Nathan Trotter & Co. product data sheet, ASTM Grade 2 Babbitt Metal (SPEC NO NT Grade 2 Babbitt, Rev. 3, 2015)
    id: ASTM B23-00 Alloy 2 on the sheet
    url: https://nathantrotter.com/wp-content/uploads/2020/09/Grade-2-Babbitt-Data.pdf
    year: 2015
    kind: datasheet
    license: supplier document, cited not reproduced
  wiki-babbitt:
    title: Babbitt metal, Wikipedia (history, BS 3332 alloy compositions, bearing uses)
    url: https://en.wikipedia.org/wiki/Babbitt_metal
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
  wiki-pewter:
    title: Pewter, Wikipedia (composition ranges and types)
    url: https://en.wikipedia.org/wiki/Pewter
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
  wiki-tin-pest:
    title: Tin pest, Wikipedia (allotropic transformation at 13.2 degC, volume increase)
    url: https://en.wikipedia.org/wiki/Tin_pest
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
  usgs-mcs2026-tin:
    title: 'Mineral Commodity Summaries 2026: Tin (U.S. Geological Survey)'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tin.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-antimony:
    title: 'Mineral Commodity Summaries 2026: Antimony (U.S. Geological Survey)'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-antimony.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  pubchem-antimony:
    title: 'PubChem compound record: Antimony (CID 5354495), experimental properties and GHS classification'
    id: CID 5354495
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5354495/JSON
    year: 2026
    kind: database
    license: PubChem (NCBI), public domain; sections attributed to ECHA and other databases
  pubchem-lead:
    title: 'PubChem compound record: Lead (CID 5352425), GHS classification'
    id: CID 5352425
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5352425/JSON
    year: 2026
    kind: database
    license: PubChem (NCBI), public domain; sections attributed to ECHA and other databases
  pubchem-tin:
    title: 'PubChem compound record: Tin (CID 5352426), experimental properties and GHS classification'
    id: CID 5352426
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5352426/JSON
    year: 2026
    kind: database
    license: PubChem (NCBI), public domain; sections attributed to ECHA, NITE-CMC and other databases
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 15
  unreachable: 0
  caveats: 5
  note: 'Values were read by an AI assistant on 2026-10-26 from the datasheets, USGS PDFs, PubChem JSON records and Wikipedia pages named in each entry. Caveats: the babbitt values come from vendor datasheets, not the ASTM standard; the two elongation figures disagree; the PubChem antimony GHS notifications do not give test conditions; the USGS antimony shares are calculated; pewter and Sn-Pb-Sb values are composition only.'
story:
  recipe:
    line: Tin-base babbitt (ASTM B23 Grade 2) is a tin alloy with about 7.5% antimony and 3.5% copper. The nominal composition is 89% tin, 7.5% antimony and 3.5% copper, within limits of 88 to 90% tin, 7 to 8% antimony and 3 to 4% copper, with lead at or below 0.35%.
    parts:
      - name: Tin
        symbol: Sn
        share_percent: 89
        role: The base metal, 88 to 90% of the alloy by the datasheet limits.
      - name: Antimony
        symbol: Sb
        share_percent: 7.5
        role: The main alloying addition, limit 7 to 8%.
      - name: Copper
        symbol: Cu
        share_percent: 3.5
        role: A second alloying addition, limit 3 to 4%.
  risk_groups:
    - title: For people
      level: 0
      verdict: Hazard codes apply to the elements
      lead: The babbitt is mostly tin, but the PubChem notifications for antimony and lead carry serious hazard codes.
      points:
        - label: Antimony
          line: PubChem notifications for antimony metal give H301 at 18.2%, H332 at 26.9% and H351 (suspected of causing cancer) at 31.8%, with signal word Danger.
        - label: Lead
          line: PubChem notifications for lead give H360 at 84.4%, which covers harm to fertility or the unborn child, and H372 at 50.5%.
        - label: Tin
          line: PubChem notifications for tin give H319 at 24.2% and H335 at 23.1%. A further notification gives H372.
    - title: If the lining overheats
      level: 1
      verdict: Melts from 241 to 354 degC
      lead: The melting range of the babbitt and the cold change of tin are the two temperature limits the sources give.
      points:
        - label: Melting range
          line: The Kapp datasheet gives a solidus of 241 degC and a liquidus of 354 degC. The alloy starts to melt at the solidus, so its strength falls before the liquidus.
        - label: Tin pest
          line: Wikipedia gives 13.2 degC as the temperature at and below which white tin changes to grey tin, with a volume increase of about 27%.
    - title: Handling and storage
      level: 2
      verdict: No handling advice for the alloy
      lead: The sources read give no handling advice for the babbitt grade itself.
      points:
        - label: Safety data
          line: Check the supplier's safety data sheet for the grade you buy. The PubChem codes above belong to the elements.
  why: Tin-base babbitt is a soft tin alloy with about 7.5% antimony and 3.5% copper. It is used as a thin running surface in plain bearings. The ASTM B23 Grade 2 grade has a density of 7.39 g/cm3, a solidus of 241 degC and a liquidus of 354 degC, and a Brinell hardness of 24.5 with a 10 mm ball and a 500 kg load. Its tensile strength is 77 MPa when chill cast. Wikipedia describes babbitt as a thin surface layer in a multi-metal bearing and says combustion engines use tin-based babbitt because it tolerates cyclic loading. Pure tin melts at 231.9 degC, so the babbitt starts to melt at a higher temperature than the pure metal.
  uses:
    - where: Engine bearings
      line: Internal combustion engines use babbitt that is primarily tin-based because it can withstand cyclic loading (Wikipedia). Poured babbitt bearings were common in cars until the mid-1950s.
    - where: Bearing metals, solder and tinning
      line: Babbitt, brass and bronze, and tinning together took 7% of U.S. tin use in 2025, and solder took 11% (USGS).
    - where: Lead-acid batteries (antimony)
      line: Antimonial lead and ammunition took 40% of U.S. antimony use in 2025, and secondary antimony was intended for the lead-acid battery industry (USGS).
  can_do:
    - label: Melt range
      value: 241 to 354 degC
      benchmark: melting_point
      line: The tin-base babbitt starts to melt at 241 degC and is fully liquid at 354 degC (Kapp). Pure tin melts at 231.9 degC.
    - label: Hardness
      value: 24.5 HB
      benchmark: brinell_hardness
      line: Brinell hardness is 24.5 at a 500 kg load with a 10 mm ball (Kapp). Chill cast, the tensile strength is 77 MPa.
    - label: Stiffness
      value: 52 GPa
      benchmark: elastic_modulus
      line: The tensile elastic modulus is 52 GPa for the alloy cast at 400 degC into a 100 degC mold (Kapp).
    - label: Fatigue
      value: 33 MPa
      benchmark: fatigue_strength
      line: Kapp gives a fatigue strength of 33 MPa at 2 x 10^7 cycles in an R.R. Moore test.
  compare: The babbitt starts to melt at 241 degC, above pure tin at 231.9 degC, and well below antimony metal at 630 degC. It is denser than antimony (7.39 against 6.68 g/cm3). The rows below compare the babbitt with those reference values.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Melting point
      benchmark: melting_point
    - label: Hardness
      benchmark: brinell_hardness
  handling:
    - Check the supplier's safety data sheet for the babbitt grade you buy; the sources read give no handling advice for the alloy.
    - Treat dust and fume from melting or machining as the PubChem codes show for tin, antimony and lead.
    - Keep the lining below its 241 degC solidus in service, and keep tin-rich parts above 13.2 degC if the change to grey tin matters.
  good_for:
    - 'Thin plain-bearing linings: the Kapp datasheet gives a Brinell hardness of 24.5 and a tensile strength of 77 MPa when chill cast.'
    - 'Engine bearings: Wikipedia says tin-based babbitt is used in combustion engines because it withstands cyclic loading.'
  watch_out:
    - 'Melting range: the babbitt begins to melt at 241 degC, well below the 630 degC melting point of antimony metal.'
    - Elongation differs by source (18% on Kapp, 8.0% on Trotter) and the Trotter figure has no test conditions.
    - 'Tin pest: below 13.2 degC, white tin can change to grey tin with a volume increase of about 27%; no test on the alloy was found.'
    - Antimony and lead carry serious PubChem hazard codes; the babbitt itself has no hazard data in the sources read.
  verdict: Tin-base babbitt is a soft, low-melting bearing alloy with a solidus of 241 degC, a Brinell hardness of 24.5 and a 77 MPa chill-cast tensile strength. Its uses are in engine bearings and as a bearing metal. Its weak points are the low melting range, the cold change of tin, and the absence of test data on corrosion, ageing and space environments. Elongation values disagree between datasheets.