Tinned copper Sn/Cu

spore: profile
id: tinned-copper
spore_version: 0.2
family: copper-alloys
name: Tinned copper
abbreviation: Sn/Cu
role: electrical conductor with a solderable tin coating
category: metals
type: copper-alloys
summary: |
  Tinned copper is copper wire, braid strand or bar with a thin tin coating, used where a copper conductor must stay solderable and resist tarnish. ASTM B33 covers tin-coated soft or annealed copper wire for electrical purposes, and the federal commercial item description A-A-59569 builds EMI shielding braid from it. Pure tin melts at 231.9 °C, conducts heat at 66.6 W/(m·K) and has a resistivity of 11.5 µΩ·cm, while the copper core is rated 58 MS/m (100 %IACS). The weak points are cold and whiskers: below 13.2 °C white tin turns to brittle grey tin, and pure tin plate can grow whiskers that short out circuits, which NASA reports caused failures of on-orbit commercial satellites.
best_for: 'Solderable, heat-conducting current paths in shields and harnesses: a 58 MS/m copper core with a tin skin, and tin-plated braid rated -65 to +150 °C'
weakest_at: 'Cold and whiskers: tin turns brittle below 13.2 °C, and pure tin plate can grow whiskers several millimetres long that bridge closely spaced circuits'
identity:
  formula: Copper core (Cu) with a thin tin (Sn) coating on soft or annealed wire, braid strands or bar; silver-coated copper is a separate product covered by ASTM B298
  cas: 7440-50-8 (copper); 7440-31-5 (tin)
  source: astm-b33
  where: Title of the ASTM B33 store page (Standard Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes). CAS 7440-31-5 from the PubChem tin record; 7440-50-8 from the PubChem copper record.
  designations:
    - system: ASTM
      code: B33
      note: tin-coated soft or annealed copper wire for electrical purposes
      source: astm-b33
      where: Page title of the ASTM store entry
tags:
  environments: []
  stresses:
    - vacuum-and-outgassing
    - extreme-cold
  applications:
    - electronics-and-chips
properties:
  - benchmark: density
    label: Density of tin
    value: 7.28
    unit: g/cm3
    scope: material
    conditions:
      form: element
      temperature: not stated on the page (NIOSH 2024 entry)
    method: Value printed in the density section of the PubChem record
    status: ground
    source: pubchem-sn
    where: Chemical and Physical Properties, Density, first entry (7.28, NIOSH 2024)
  - benchmark: density
    label: Density of silver
    value: 10.49
    unit: g/cm3
    scope: material
    conditions:
      form: metal
      temperature: 15 °C
    method: Value printed in the density section of the PubChem record
    status: ground
    source: pubchem-ag
    where: Chemical and Physical Properties, Density, entry 10.49 @ 15 °C
  - benchmark: melting_point
    label: Melting point of tin
    value: 231.9
    unit: °C
    scope: material
    conditions:
      form: element
      pressure: not stated
    method: Value printed in the melting point section of the PubChem record
    status: ground
    source: pubchem-sn
    where: Chemical and Physical Properties, Melting Point, entry 231.9 °C
  - benchmark: melting_point
    label: Melting point of silver
    value: 961.78
    unit: °C
    scope: material
    conditions:
      form: metal
      pressure: not stated
    method: Value printed in the melting point section of the PubChem record
    status: ground
    source: pubchem-ag
    where: Chemical and Physical Properties, Melting Point, entry 961.78 °C
  - benchmark: allotropic_transformation_temperature
    label: White (beta) to grey (alpha) tin transformation temperature
    value: 13.2
    unit: °C
    scope: material
    conditions:
      basis: beta tin in equilibrium with alpha tin
    method: Value printed in the melting point section of the PubChem record (non-canonical property name)
    status: ground
    source: pubchem-sn
    where: Chemical and Physical Properties, Melting Point, entry 'Transformation temp (beta in equilibrium with alpha) 13.2 °C'
  - benchmark: thermal_conductivity
    label: Thermal conductivity of tin
    value: 66.6
    unit: W/(m·K)
    scope: material
    conditions:
      form: polycrystalline
      temperature: not stated on the page
    method: Value printed on a reference-database physical properties page
    status: ground
    source: webelements-sn
    where: Heat and conduction, Thermal conductivity, polycrystalline value
  - benchmark: thermal_conductivity
    label: Thermal conductivity of silver
    value: 430
    unit: W/(m·K)
    scope: material
    conditions:
      form: element
      temperature: not stated on the page
    method: Value printed on a reference-database physical properties page
    status: ground
    source: webelements-ag
    where: Heat and conduction, Thermal conductivity
  - benchmark: electrical_resistivity
    label: Electrical resistivity of tin
    value: 11.5
    unit: µΩ·cm
    scope: material
    conditions:
      form: element
      temperature: not stated on the page
      unit_in_source: 11.5 × 10-8 Ω m
    method: 'Printed as 11.5 × 10-8 Ω m on the WebElements page (its label reads mΩ cm, which does not match the number). Converted here to µΩ·cm, since 1 Ω m is 100 Ω cm, so the value is unchanged in magnitude: 11.5 µΩ·cm.'
    status: ground
    source: webelements-sn
    where: Electrical properties, Electrical resistivity
  - benchmark: electrical_resistivity
    label: Electrical resistivity of silver
    value: 1.63
    unit: µΩ·cm
    scope: material
    conditions:
      form: element
      temperature: not stated on the page
      unit_in_source: 1.63 × 10-8 Ω m
    method: Printed as 1.63 × 10-8 Ω m on the WebElements page. Converted to µΩ·cm the same way as the tin value (1 Ω m is 100 Ω cm).
    status: ground
    source: webelements-ag
    where: Electrical properties, Electrical resistivity
  - benchmark: elastic_modulus
    label: Young's modulus of tin
    value: 50
    unit: GPa
    scope: material
    conditions:
      form: solid element
    method: Value printed on a reference-database physical properties page
    status: ground
    source: webelements-sn
    where: Elastic properties, Young's modulus
  - benchmark: cte
    label: Coefficient of linear thermal expansion of tin
    value: 22
    unit: ppm/K
    scope: material
    conditions:
      temperature: not stated on the page
      unit_in_source: 22 × 10-6 K-1
    method: Value printed on a reference-database physical properties page
    status: ground
    source: webelements-sn
    where: Heat and conduction, Coefficient of linear thermal expansion
  - benchmark: whisker_length
    label: Tin whisker length, observed in pure tin plate
    value: 10
    bound: lower
    unit: mm
    scope: material
    conditions:
      basis: whiskers grown from pure tin plate; several millimetres are common, lengths over 10 mm are rare
    method: 'Statement in a NASA Goddard background page: lengths of several millimetres, and in rare instances over 10 mm (non-canonical property name)'
    status: ground
    source: nasa-whisker
    where: Background page, Whisker Length paragraph
  - benchmark: whisker_diameter
    label: Tin whisker diameter, lower end of reported range
    value: 100
    bound: lower
    unit: nm
    scope: material
    conditions:
      basis: typical diameters are a few microns; rarely less than 100 nm
    method: Statement in a NASA Goddard background page (non-canonical property name)
    status: ground
    source: nasa-whisker
    where: Background page, Whisker Diameter paragraph
  - benchmark: coating_thickness
    label: Minimum silver coating on silver-coated copper braid
    value: 40
    bound: lower
    unit: micro-inches
    scope: material
    conditions:
      product: silver-coated copper braid under A-A-59569
      applies_to: silver coating only, not tin
    method: Minimum thickness printed in a federal commercial item description (non-canonical property name)
    status: ground
    source: cid-a-a-59569
    where: Section 3.2 Materials
  - benchmark: max_service_temp
    label: Upper temperature, tin-plated copper screening braid
    value: 150
    unit: °C
    scope: material
    conditions:
      product: tin-plated copper screening braid
      note: the same datasheet gives +260 °C for the nickel-plated version
    method: Value printed in the Features list of a supplier datasheet
    status: ground
    source: farnell-3812260
    where: Features list, bullet 'Tin Plated'
  - benchmark: min_service_temp
    label: Lower temperature, tin-plated copper screening braid
    value: -65
    unit: °C
    scope: material
    conditions:
      product: tin-plated copper screening braid
    method: Value printed in the Features list of a supplier datasheet
    status: ground
    source: farnell-3812260
    where: Features list, bullet 'Tin Plated'
  - benchmark: electrical_conductivity
    label: Electrical conductivity of the copper core, soft oxygen-free grade
    value: 58
    unit: MS/m
    scope: material
    conditions:
      grade: C10200 (Cu-OF)
      temper: soft
      equivalent_in_source: 100 %IACS
    method: Value printed in a manufacturer datasheet
    status: ground
    source: aurubis-c10200
    where: Physical properties table, Electrical cond. [MS/m] column, soft row
  - benchmark: density
    label: Density of the copper core, C10200
    value: 8.9
    unit: g/cm3
    scope: material
    conditions:
      grade: C10200 (Cu-OF)
    method: Value printed in a manufacturer datasheet
    status: ground
    source: aurubis-c10200
    where: Physical properties table, Density [g/cm3] column
  - benchmark: thermal_conductivity
    label: Thermal conductivity of the copper core, C10200 at 20 °C
    value: 391
    unit: W/(m·K)
    scope: material
    conditions:
      grade: C10200 (Cu-OF)
      temperature: 20 °C
    method: Value printed in a manufacturer datasheet
    status: ground
    source: aurubis-c10200
    where: Physical properties table, Thermal cond. [W/mK] column
corrosion:
  - environment: Humid air, bulk tin
    headline: Bulk tin is stable in air, but powdered tin oxidizes, especially with moisture.
    effect: PubChem's stability entry for tin says it is stable in air, but in powder form it oxidizes, especially in the presence of moisture. The sources read give no rate for a tin coating on copper.
    rating: low
    conditions:
      form: bulk metal in air; powder with moisture
    source: pubchem-sn
    where: Chemical and Physical Properties, Stability/Shelf Life
  - environment: Cold, below 13.2 °C
    headline: Below 13.2 °C, white tin changes to brittle grey tin, which crumbles.
    effect: PubChem gives 13.2 °C as the transformation point. At -40 °C tin crumbles to a grey amorphous powder (grey tin), and it changes back to white tin slowly above 20 °C. The transformation rate is not given in the sources read.
    rating: moderate
    conditions:
      basis: allotrope change in cold storage; no transformation rate in the source
    source: pubchem-sn
    where: Color/Form (crumbles at -40 °C); Melting Point (transformation 13.2 °C)
  - environment: Air containing sulfur compounds or ozone (silver coating)
    headline: Silver tarnishes in air containing sulfur or ozone, forming a dark surface film.
    effect: PubChem says silver is stable in air and water but tarnishes when exposed to ozone, hydrogen sulfide or air containing sulfur. Silver sulfide, a dark-grey to black film, is named in the hazards summary. No tarnish rate or contact-resistance change was found in the sources read.
    rating: moderate
    conditions:
      basis: qualitative statement; no exposure time or rate given
    source: pubchem-ag
    where: Chemical and Physical Properties, Stability/Shelf Life; Safety and Hazards, Hazards Summary
risks:
  hazards:
    - text: 'PubChem''s aggregated GHS section for tin: the substance does not meet GHS hazard criteria in 72.9% (695 of 953) of company reports. The codes given are H319 (causes serious eye irritation, 24.2%) and H335 (may cause respiratory irritation, 23.1%), signal word Warning.'
      ghs:
        - H319
        - H335
      source: pubchem-sn
      where: Safety and Hazards, GHS Classification (aggregated reports)
    - text: PubChem's aggregated GHS section for silver lists H361f (suspected of damaging fertility), H373 (may cause damage to organs through prolonged or repeated exposure), H400 (very toxic to aquatic life) and H410 (very toxic to aquatic life with long lasting effects).
      ghs:
        - H361f
        - H373
        - H400
        - H410
      source: pubchem-ag
      where: Safety and Hazards, GHS Classification, signal word Warning
    - text: PubChem's copper record, from the ECHA C&L Inventory, lists H302, H400 and H410 among the codes given by notifiers for the copper core. The record notes that classification varies with impurities and form.
      ghs:
        - H302
        - H400
        - H410
      source: pubchem-cu
      where: GHS Classification, ECHA C&L Inventory
  failure_risks:
    - mode: Tin whisker short circuit
      trigger: Pure tin plate on copper or other substrates; growth varies with plating chemistry, thickness, substrate, grain structure and storage conditions
      consequence: Whiskers bridge closely spaced circuit elements. NASA reports at least three tin whisker short circuits that caused complete failure of on-orbit commercial satellites, and whisker-induced failures in medical devices, weapon systems, power plants and consumer products.
      severity: high
      source: nasa-whisker
      where: Background page, introduction and Whisker Growth Factors
    - mode: Metal vapour arc in vacuum after a whisker short
      trigger: A whisker-initiated short in a vacuum environment, as in spacecraft electronics
      consequence: NASA reports metal vapour arcs in vacuum on at least three commercial satellites, which blew fuses and left the spacecraft non-operational.
      severity: high
      source: nasa-whisker
      where: Background page, section on vacuum arcing and cited Richardson and Lasley paper
    - mode: Tin pest in cold storage
      trigger: Exposure below the 13.2 °C transformation point for a long time
      consequence: The tin becomes brittle grey tin, which crumbles to powder at low temperature. The sources read give no time scale for this, so tin pest may matter only for long cold storage.
      severity: moderate
      source: pubchem-sn
      where: Color/Form and Melting Point entries
    - mode: Silver coating tarnish
      trigger: Sulfur compounds or ozone in the air, with silver-coated braid
      consequence: A tarnish film forms on the silver. The sources read do not report an effect on contact resistance or shielding.
      severity: low
      source: pubchem-ag
      where: Stability/Shelf Life; Hazards Summary
  side_effects: []
  handling:
    - text: PubChem lists strong oxidizers, hydrogen peroxide and acids as incompatible with tin, and reports that tin is combustible in fire.
      source: pubchem-sn
      where: Safety and Hazards, Hazardous Reactivities and Incompatibilities; Fire Hazards
    - text: Specify the coating and the temper on the order. ASTM B33 and the federal item description both require tin or silver coatings to be solderable; the commercial description requires good solderability to MIL-STD-202 method 208.
      source: cid-a-a-59569
      where: Section 3.5 Solderability; Section 3.2 Materials
  mitigations:
    - text: NASA GSFC suggests stripping pure tin plate and re-plating with a tin-lead or nickel finish, and warns that a finish laid over an existing pure tin deposit has its own risks.
      source: nasa-whisker
      where: Background page, mitigation paragraph
    - text: NASA GSFC experiments showed that a conformal coating (Arathane 5750) applied uniformly to a nominal 2 to 3 mils thickness helps contain whisker growth outward through the coating.
      source: nasa-whisker
      where: Background page, mitigation paragraph
uses:
  - application: electronics-and-chips
    device: EMI and RF shielding braid for wire and cable harnesses
    example: Farnell's copper screening braid is sold in tin-plated or nickel-plated form to protect harnesses from electromagnetic, electrostatic and radio frequency interference, with a -65 to +150 °C range for the tin-plated version.
    source: farnell-3812260
    where: Features list and part number table
  - application: electronics-and-chips
    device: Tin-plated copper braid for military and industrial EMI/RFI shielding
    example: Glenair describes its tin-plated copper braid, part 100-001, as industry-standard EMI/RFI shielding, drawn to A-A-59569 and built from wire to ASTM B33.
    source: glenair-100-001
    where: Page title, description and the note 'Copper/Tin Plate I.A.W ASTM B33'
  - application: electronics-and-chips
    device: Harness shielding and grounding braid
    example: MBN Flexo sells tinned copper braid for shielding on harnesses and cables and for grounding, with a wire thickness of 0.005 to 0.010 inch.
    source: mbn-flexo
    where: Product description and specification table
supply:
  - subject: Tin
    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
    critical_lists: []
    recycling: 'USGS: about 17000 tons of tin from old and new scrap was recycled in 2025, which the USGS says is 22% of apparent consumption.'
    substitutes:
      - 'USGS: aluminum, glass, paper, plastic or tin-free steel substitute for tin in cans and containers, and epoxy resins can replace solder.'
    source: usgs-mcs2026-tin
    where: World Mine Production and Reserves table, 2025e (world total 290000 t, tin content; shares calculated by Space Mushroom from the country values 71000, 61000, 33000 and 28000 t); Recycling; Substitutes
  - subject: Silver
    producers:
      - country: Mexico
        share_percent: 24.2
        year: 2025
      - country: Peru
        share_percent: 13.8
        year: 2025
      - country: China
        share_percent: 13.1
        year: 2025
    critical_lists:
      - list: U.S. Final 2025 List of Critical Minerals (silver added in 2025, per the USGS silver summary)
        listed: true
    recycling: 'USGS: in 2025 about 1000 tons of silver was recovered from new and old scrap, about 11% of apparent consumption.'
    substitutes:
      - 'USGS: stainless steel, tantalum and titanium can replace silver in some surgical items, and aluminum and rhodium can replace it in mirrors.'
    source: usgs-mcs2026-silver
    where: World Mine Production and Reserves table, 2025e (world total 26000 t, silver content; shares calculated by Space Mushroom from the country values 6300, 3600 and 3400 t); Recycling; Substitutes; list changes in the summary
documents:
  - title: 'ASTM B33: Standard Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes (ASTM store page)'
    type: standard
    url: https://store.astm.org/b0033-10r14.html
  - title: 'Commercial item description A-A-59569C: Braid, wire (copper, tin-coated, silver-coated, or nickel coated, tubular or flat), GSA and federal agencies (2009)'
    type: standard
    url: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/7161/AA59569.pdf
    year: 2009
  - title: Glenair 100-001 industry-standard tin-plated copper braid EMI/RFI shielding datasheet
    type: datasheet
    url: https://www.glenair.com/braided-shielding-and-sleeving/emi-rfi-tubular-expandable-braided-shielding/pdf/100-001.pdf
  - title: Farnell copper screening braid, tin or nickel plated, datasheet 3812260
    type: datasheet
    url: https://www.farnell.com/datasheets/3812260.pdf
  - title: MBN Flexo tinned copper braid product sheet
    type: datasheet
    url: https://www.cableorganizer.com/cdn/shop/files/MBN-Flexo_Tinned_Copper.pdf
  - title: 'PubChem compound record: Tin (JSON view, GHS, density and melting point)'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5352426/JSON
  - title: 'PubChem compound record: Silver (JSON view, GHS, density and melting point)'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23954/JSON
  - title: 'PubChem compound record: Copper (JSON view, atomic weight and GHS)'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23978/JSON
  - title: 'WebElements: Tin, physics properties'
    type: database
    url: https://www.webelements.com/tin/physics.html
  - title: 'WebElements: Silver, physics properties'
    type: database
    url: https://www.webelements.com/silver/physics.html
  - title: NASA GSFC Tin Whisker background (NEPP)
    type: report
    url: https://nepp.nasa.gov/whisker/background/index.htm
  - title: 'USGS Mineral Commodity Summaries 2026: Tin'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tin.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Silver'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf
    year: 2026
  - title: Aurubis technical datasheet C10200 (Cu-OF), 18 08 US
    type: datasheet
    url: https://www.aurubis.be/en/dam/jcr:90029b00-b968-486e-bde0-ce56f16022cd/c10200-cu-of-us.pdf
gaps:
  - ASTM B546 could not be identified. The search returned only ASTM B545 (electrodeposited coatings of tin) and the ASTM store pages were not readable, so no B546 title or value is used. Confirm the intended standard.
  - ASTM B33 text was not readable from the ASTM store, so its resistivity limits, tin coating thickness and conductor sizes are not recorded. Vendor resistance-per-length figures found in search snippets were not fetched and are not used.
  - Tin coating thickness on tinned copper wire, braid or busbar was not found in a source read in this run.
  - 'Busbar: distributor listings for tin-plated copper busbar were found (Eaton, Siemens), but the RS Components page refused access, so no busbar value or source is recorded.'
  - 'Tin critical-mineral status: the USGS tin summary does not state it, and the USGS 2025 list page and the EU critical raw materials list were not read for tin, so critical_lists is empty.'
  - Tin electrical conductivity in percent IACS was not read; resistivity is recorded instead, in µΩ·cm converted from the printed Ω m value.
  - 'Copper-tin intermetallic growth on wire: a repository record in search results was not opened, so no growth rate is recorded. The room-temperature growth statement is therefore absent.'
  - No NASA outgassing (total mass loss), atomic oxygen erosion or radiation result for tin, silver or tin-plated copper was found in a source read in this run.
  - 'Non-canonical property names used: whisker_length, whisker_diameter, allotropic_transformation_temperature and coating_thickness. Each is defined in its own property entry.'
  - Silver tarnish has no rate or contact-resistance value in the sources read.
  - The PubChem GHS percentages for silver are not recorded because the silver record gives its codes without shares.
sources:
  pubchem-sn:
    title: 'PubChem compound record: Tin (CID 5352426), experimental properties, GHS classification and reactivity'
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5352426/JSON
    year: 2026
    kind: database
    license: PubChem (NCBI), public domain; some sections attributed to ECHA, HSDB and NTP (cited, not reproduced)
  pubchem-ag:
    title: 'PubChem compound record: Silver (CID 23954), experimental properties, GHS classification and hazards summary'
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23954/JSON
    year: 2026
    kind: database
    license: PubChem (NCBI), public domain (cited, not reproduced)
  pubchem-cu:
    title: 'PubChem compound record: Copper (CID 23978), atomic weight and ECHA C&L Inventory classification'
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23978/JSON
    year: 2026
    kind: database
    license: PubChem (NCBI), public domain (cited, not reproduced)
  webelements-sn:
    title: 'WebElements: Tin, physics properties'
    url: https://www.webelements.com/tin/physics.html
    kind: database
    license: WebElements (cited, not reproduced)
  webelements-ag:
    title: 'WebElements: Silver, physics properties'
    url: https://www.webelements.com/silver/physics.html
    kind: database
    license: WebElements (cited, not reproduced)
  nasa-whisker:
    title: 'NASA Goddard Space Flight Center, Tin Whisker (and Other Metal Whisker) Homepage: background'
    url: https://nepp.nasa.gov/whisker/background/index.htm
    kind: report
    license: NASA public web page
  astm-b33:
    title: 'ASTM B33: Standard Specification for Tin-Coated Soft or Annealed Copper Wire for Electrical Purposes'
    url: https://store.astm.org/b0033-10r14.html
    kind: standard
    license: ASTM store page (title read, standard text not read)
  cid-a-a-59569:
    title: 'Commercial item description A-A-59569C: Braid, wire (copper, tin-coated, silver-coated, or nickel coated, tubular or flat)'
    id: A-A-59569C, 22 January 2009
    url: https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/7161/AA59569.pdf
    year: 2009
    kind: standard
    license: U.S. government commercial item description (cited, not reproduced)
  glenair-100-001:
    title: Glenair 100-001 industry-standard metallic EMI/RFI braided shielding, tin-plated copper braid
    url: https://www.glenair.com/braided-shielding-and-sleeving/emi-rfi-tubular-expandable-braided-shielding/pdf/100-001.pdf
    kind: datasheet
    license: Manufacturer datasheet (cited, not reproduced)
  farnell-3812260:
    title: Copper Screening Braid, Tin or Nickel Plated (Farnell datasheet 3812260)
    url: https://www.farnell.com/datasheets/3812260.pdf
    kind: datasheet
    license: Supplier datasheet (cited, not reproduced)
  mbn-flexo:
    title: MBN Flexo Tinned Copper braid product sheet
    url: https://www.cableorganizer.com/cdn/shop/files/MBN-Flexo_Tinned_Copper.pdf
    kind: datasheet
    license: Supplier datasheet (cited, not reproduced)
  usgs-mcs2026-tin:
    title: Mineral Commodity Summaries 2026, Tin
    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-silver:
    title: Mineral Commodity Summaries 2026, Silver
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silver.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  aurubis-c10200:
    title: Technical Datasheet C10200 (Cu-OF), Aurubis, version 18 08 US
    id: UNS C10200; ASTM B152
    url: https://www.aurubis.be/en/dam/jcr:90029b00-b968-486e-bde0-ce56f16022cd/c10200-cu-of-us.pdf
    kind: datasheet
    license: Manufacturer leaflet, general information only (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 19
  unreachable: 3
  caveats: 4
  note: 'Written by an AI assistant on 2026-10-26 from pages read in this run. Unreachable: ASTM B33 and B298 text (store pages blocked), the RS Components busbar listing, and ASTM B546 (not identified). Caveats: tin resistivity is converted from a printed Ω m value; the braid temperatures are product limits; the silver GHS codes are aggregated; no tin coating thickness was found.'
story:
  recipe:
    line: Tinned copper is copper (Cu, face-centred cubic, a single element) with a thin layer of tin (Sn) on its surface. The tin is deposited on the finished wire, strand or bar, and ASTM B33 governs the wire and coating. The silver-coated variant is a separate product (ASTM B298).
    parts:
      - name: Copper
        symbol: Cu
        share: 'The core: the whole conductor by mass; the coating is thin'
        role: Carries the current.
      - name: Tin
        symbol: Sn
        share: A surface layer only; its thickness is not recorded here
        role: Coats the copper to keep it solderable and resistant to tarnish.
  risk_groups:
    - title: For people
      lead: The tin coating is not classified as hazardous in most reports, but the silver coating and the copper core are classified in PubChem.
      level: 1
      verdict: Low for tin, classified for silver
      points:
        - label: Tin
          line: PubChem records that tin does not meet the GHS criteria in 72.9% of company reports. The codes given are H319 (serious eye irritation) and H335 (respiratory irritation), with signal word Warning.
        - label: Silver
          line: PubChem's aggregated silver record lists H361f, H373, H400 and H410, including fertility and aquatic hazards.
        - label: Copper
          line: The copper record lists H302, H400 and H410 among the codes given by notifiers.
    - title: If it fails
      lead: These routes come from the sources read. Two are measured in space hardware; the cold route is a material property with no time scale given.
      points:
        - label: Whisker shorts
          line: Pure tin plate can grow whiskers that bridge circuit spacings. NASA reports at least three commercial satellites with complete failure from whisker short circuits.
        - label: Vacuum arcs
          line: In vacuum, a whisker short can cause a metal vapour arc. NASA reports at least three commercial satellites with blown fuses from such arcs.
        - label: Cold
          line: Below 13.2 °C, white tin turns to brittle grey tin, which crumbles at low temperature.
    - title: Handling and storage
      points:
        - label: Incompatibilities
          line: PubChem lists strong oxidizers, hydrogen peroxide and acids as incompatible with tin, and reports that tin is combustible in a fire.
        - label: Solderability
          line: The federal commercial item description requires good solderability for tin-coated braid, tested to MIL-STD-202 method 208.
  why: Tinned copper keeps the high conductivity of copper and adds a tin skin that is easy to solder and resists tarnish. The copper core is rated 58 MS/m (100 %IACS) in the soft oxygen-free grade, and its thermal conductivity is 391 W/(m·K) at 20 °C. Tin adds solderability and a melting point of 231.9 °C. Shield braid built from tin-plated copper is sold for EMI and RF protection of harnesses, with a tin-plated range of -65 to +150 °C. The cost of the tin skin is the whisker risk, and in cold storage the tin can turn brittle. Silver coating is an alternative where the coating must conduct better or resist more heat.
  uses:
    - where: EMI shielding
      line: Farnell sells copper screening braid in tin-plated or nickel-plated form to protect harnesses from electromagnetic, electrostatic and radio frequency interference. The tin-plated version is rated -65 to +150 °C.
    - where: Military and industrial braid
      line: Glenair's tin-plated copper braid, part 100-001, is built to ASTM B33 and drawn to A-A-59569. Glenair calls it the industry-standard metallic EMI/RFI shield.
    - where: Harness shielding and grounding
      line: MBN Flexo sells tinned copper braid for shielding on harnesses and cables and for grounding, in wire thicknesses of 0.005 to 0.010 inch.
  can_do:
    - label: Carry current
      value: 58 MS/m (100 %IACS)
      line: The soft oxygen-free copper core conducts at 58 MS/m, the 100 %IACS reference. The datasheet says this applies to the soft condition only.
    - label: Carry heat
      value: 391 W/(m·K)
      benchmark: thermal_conductivity
      line: The copper core conducts heat at 391 W/(m·K) at 20 °C. Tin conducts at 66.6 W/(m·K), and silver at 430 W/(m·K).
    - label: Solder
      value: 231.9 °C tin melting point
      benchmark: melting_point
      line: Tin melts at 231.9 °C, which is the temperature range used for common solder work. The federal item description requires good solderability for tinned braid.
    - label: Shield temperature
      value: '-65 to +150 °C'
      benchmark: max_service_temp
      line: The tin-plated copper screening braid is rated -65 to +150 °C in the Farnell datasheet, and the nickel-plated version to +260 °C.
  compare: Among the three coating and core metals, copper conducts heat best at 391 W/(m·K), against 66.6 W/(m·K) for tin. Silver conducts at 430 W/(m·K) but costs more and tarnishes. Tin is the lightest coating at 7.28 g/cm3 against 10.49 g/cm3 for silver and 8.9 g/cm3 for the copper core.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Melting point
      benchmark: melting_point
    - label: Thermal conductivity
      benchmark: thermal_conductivity
  handling:
    - 'Specify the coating and temper: the conductivity figure applies to the soft copper core, and tin is what keeps the wire solderable.'
    - Keep tin-coated parts above 13.2 °C for long storage, to avoid tin pest.
    - Protect the wire from strong oxidizers and acids, which PubChem lists as incompatible with tin.
    - On a whisker-prone pure tin finish, consider a tin-lead or nickel underlayer or finish, and a conformal coating, as NASA suggests.
  good_for:
    - 'Solderable current paths: 58 MS/m copper core with a tin skin, and the federal item description requires good solderability for tinned braid.'
    - EMI shielding for harnesses, with tin-plated braid rated -65 to +150 °C.
    - 'Heat conduction: 391 W/(m·K) in the copper core at 20 °C.'
  watch_out:
    - 'Whiskers: pure tin plate can grow whiskers several millimetres long, and at least three commercial satellites failed from whisker shorts.'
    - 'Cold: white tin turns to brittle grey tin below 13.2 °C.'
    - 'Tarnish: the silver coating tarnishes in sulfur-bearing air or ozone.'
    - No tin coating thickness, busbar figure or NASA outgassing result was found for this profile.
  verdict: Tinned copper is the solderable, heat-conducting option for shields and harnesses. The copper core carries the current, and the tin skin keeps it solderable. Pure tin plate can grow whiskers and turns brittle below 13.2 °C, so it suits shields and harnesses better than long-term space hardware without a whisker mitigation.