Platinum Pt

spore: profile
id: platinum
spore_version: 0.2
family: precious-metals
name: Platinum
abbreviation: Pt
role: contact, catalyst and high-temperature sensing metal
category: metals
type: precious-metals
summary: |
  Platinum is the element Pt, a dense, ductile precious metal with a melting point of about 1769 °C. The Heraeus datasheet gives a density of 21.45 g/cm3 and a thermal conductivity of 74 W/(m·K) at 20 °C, and the Wikipedia infobox gives 21.452 g/cm3 at 20 °C. Annealed platinum has a yield strength of 70 MPa and a tensile strength of 150 MPa, and it stretches 40 % before breaking. The Space Shuttle Orbiter carried platinum resistance thermometers and platinum-rhodium thermocouples to measure temperatures on its skin and heat tiles, and a NASA contractor report used platinum-rhodium thermocouples to measure gas temperatures in a liquid-rocket injector.
best_for: 'Stable high-temperature sensing and electrical contacts: a platinum resistance element is linear and stable over a wide temperature range (Columbia Accident Investigation Board)'
weakest_at: Softness in the annealed state (70 MPa yield), flammability of fine powder (PubChem hazard H228), and cost against cheaper metals
identity:
  formula: Pt (element, atomic number 78); refined grades of 99.95 % and 99.99 % minimum purity (ASTM B561)
  cas: 7440-06-4
  crystal_system: face-centred cubic
  source: vem-pt
  where: Chemical Properties section of the VEM platinum page (atomic number 78, atomic weight 195.08, crystal structure Face-Centered Cubic). CAS 7440-06-4 from the CAS section of the PubChem record for platinum (CID 23939).
  designations:
    - system: ASTM
      code: B0561-23
      note: refined platinum specification, as printed in the title; grade 99.95 carries the UNS number PO4995 in the source
      source: astm-b561
      where: Title block and section 1.1 grade list
tags:
  environments:
    - re-entry
  stresses: []
  applications:
    - thermal-control
    - propulsion-and-tanks
    - electronics-and-chips
properties:
  - benchmark: density
    label: Density, general information of the Heraeus platinum datasheet
    value: 21.45
    unit: g/cm3
    scope: material
    conditions:
      form: Pt, wire, sheet and tube (Heraeus product forms)
      temperature: not stated in the table
      unit_in_source: g/cm³
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: General information table, row Density, g/cm³
  - benchmark: density
    label: Density at 20 °C (Wikipedia infobox)
    value: 21.452
    unit: g/cm3
    scope: material
    conditions:
      form: element, platinum metal
      temperature: 20 °C
    method: Value printed in the infobox of the Wikipedia article for platinum
    status: ground
    source: wikipedia-pt
    where: Infobox, Physical properties, density at 20 °C
  - benchmark: melting_point
    label: Melting point, Heraeus datasheet
    value: 1769
    unit: °C
    scope: material
    conditions:
      form: Pt, wire, sheet and tube
      pressure: not stated
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: General information table, row Melting Point, °C
  - benchmark: melting_point
    label: Melting point (Wikipedia infobox)
    value: 1768.3
    unit: °C
    scope: material
    conditions:
      form: element, platinum metal
      unit_in_source: 2041.4 K
      pressure: not stated
    method: Value printed in the infobox of the Wikipedia article for platinum
    status: ground
    source: wikipedia-pt
    where: Infobox, Physical properties, melting point
  - benchmark: boiling_point
    label: Boiling point (Wikipedia infobox)
    value: 3825
    unit: °C
    scope: material
    conditions:
      form: element, platinum metal
      unit_in_source: 4098 K
      pressure: not stated
    method: Value printed in the infobox of the Wikipedia article for platinum
    status: ground
    source: wikipedia-pt
    where: Infobox, Physical properties, boiling point
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 20 °C, Heraeus datasheet
    value: 74
    unit: W/(m·K)
    scope: material
    conditions:
      form: Pt, wire, sheet and tube
      temperature: 20 °C
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: Physical properties table, row Thermal Conductivity at 20 °C, W/(m*K)
  - benchmark: thermal_conductivity
    label: Thermal conductivity (Wikipedia infobox)
    value: 71.6
    unit: W/(m·K)
    scope: material
    conditions:
      form: element, platinum metal
      temperature: not stated in the infobox
    method: Value printed in the infobox of the Wikipedia article for platinum
    status: ground
    note: The Heraeus value is 74 W/(m·K) at 20 °C; the Wikipedia value has no temperature. The gap between them is about 3 %.
    source: wikipedia-pt
    where: Infobox, Physical properties, thermal conductivity
  - benchmark: electrical_resistivity
    label: Electrical resistivity at 20 °C (VEM platinum page)
    value: 10.6
    unit: µΩ·cm
    scope: material
    conditions:
      form: platinum metal
      temperature: 20 °C
    method: Value printed on a supplier's material page
    status: ground
    source: vem-pt
    where: Physical Properties section, electrical resistivity
  - benchmark: electrical_resistivity
    label: Electrical resistivity at 20 °C (Wikipedia infobox)
    value: 105
    unit: nΩ·m
    scope: material
    conditions:
      form: element, platinum metal
      temperature: 20 °C
    method: Value printed in the infobox of the Wikipedia article for platinum
    status: ground
    note: 105 nΩ·m is the same quantity as the VEM value of 10.6 µΩ·cm (1 µΩ·cm is 10 nΩ·m), so the two agree within about 1 %.
    source: wikipedia-pt
    where: Infobox, Other properties, electrical resistivity at 20 °C
  - benchmark: electrical_conductivity
    label: Electrical conductivity range, Heraeus datasheet
    value: 15.78
    value_high: 16.07
    bound: range
    unit: '% IACS'
    scope: material
    conditions:
      form: Pt, wire, sheet and tube
      temperature: not stated in the table
    method: Minimum and maximum printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: Physical properties table, rows Conductivity, min., % IACS and Conductivity, max., % IACS
  - benchmark: elastic_modulus
    label: Young's modulus, Heraeus datasheet
    value: 170
    unit: GPa
    scope: material
    conditions:
      form: Pt, wire, sheet and tube
      temperature: not stated in the table
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: Physical properties table, row Young's Modulus, GPa
  - benchmark: elastic_modulus
    label: Young's modulus (Wikipedia infobox)
    value: 168
    unit: GPa
    scope: material
    conditions:
      form: element, platinum metal
      temperature: not stated in the infobox
    method: Value printed in the infobox of the Wikipedia article for platinum
    status: ground
    source: wikipedia-pt
    where: Infobox, Physical properties, Young's modulus
  - benchmark: shear_modulus
    label: Modulus of rigidity (shear), Heraeus datasheet
    value: 66
    unit: GPa
    scope: material
    conditions:
      form: Pt, wire, sheet and tube
      temperature: not stated in the table
    method: Value printed in a manufacturer datasheet
    status: ground
    note: The Wikipedia infobox gives 61 GPa for shear modulus. The two sources differ by about 8 %.
    source: heraeus-pt
    where: Physical properties table, row Modulus of Rigidity, GPa
  - benchmark: shear_modulus
    label: Shear modulus (Wikipedia infobox)
    value: 61
    unit: GPa
    scope: material
    conditions:
      form: element, platinum metal
      temperature: not stated in the infobox
    method: Value printed in the infobox of the Wikipedia article for platinum
    status: ground
    source: wikipedia-pt
    where: Infobox, Other properties, shear modulus
  - benchmark: cte
    label: Coefficient of thermal expansion at 20 °C (Wikipedia infobox)
    value: 8.93
    unit: ppm/K
    scope: material
    conditions:
      form: element, platinum metal
      temperature: 20 °C
      unit_in_source: 8.93×10−6/K
    method: Value printed in the infobox of the Wikipedia article for platinum
    status: ground
    source: wikipedia-pt
    where: Infobox, Other properties, thermal expansion at 20 °C
  - benchmark: specific_heat
    label: Specific heat capacity (Wikipedia infobox)
    value: 132.561
    unit: J/(kg·K)
    scope: material
    conditions:
      form: element, platinum metal
      temperature: not stated in the infobox
    method: Value printed in the infobox of the Wikipedia article for platinum
    status: ground
    source: wikipedia-pt
    where: Infobox, Physical properties, specific heat capacity
  - benchmark: vickers_hardness
    label: Vickers hardness, annealed, Heraeus datasheet
    value: 42
    unit: HV
    scope: material
    conditions:
      temper: annealed
      form: Pt, wire, sheet and tube
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: Mechanical properties table, row Hardness HV, column Annealed
  - benchmark: vickers_hardness
    label: Vickers hardness, work hardened, Heraeus datasheet
    value: 98
    unit: HV
    scope: material
    conditions:
      temper: work hardened
      form: Pt, wire, sheet and tube
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: Mechanical properties table, row Hardness HV, column Work Hardened
  - benchmark: hardness_brinell
    label: Brinell hardness (Wikipedia infobox)
    value: 300
    value_high: 500
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: element, platinum metal
      temperature: not stated in the infobox
    method: Range printed in the infobox of the Wikipedia article for platinum
    status: ground
    source: wikipedia-pt
    where: Infobox, Other properties, Brinell hardness
  - benchmark: yield_strength
    label: Yield strength Rp0.2, annealed, Heraeus datasheet
    value: 70
    unit: MPa
    scope: material
    conditions:
      temper: annealed
      form: Pt, wire, sheet and tube
      temperature: not stated in the table
    method: Value printed in a manufacturer datasheet
    status: ground
    note: The same table gives 290 MPa for the work-hardened temper, so the strength depends strongly on temper.
    source: heraeus-pt
    where: Mechanical properties table, row Yield Strength, MPa, column Annealed
  - benchmark: yield_strength
    label: Yield strength, work hardened, Heraeus datasheet
    value: 290
    unit: MPa
    scope: material
    conditions:
      temper: work hardened
      form: Pt, wire, sheet and tube
      temperature: not stated in the table
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: Mechanical properties table, row Yield Strength, MPa, column Work Hardened
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, annealed, Heraeus datasheet
    value: 150
    unit: MPa
    scope: material
    conditions:
      temper: annealed
      form: Pt, wire, sheet and tube
      temperature: not stated in the table
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: Mechanical properties table, row Tensile Strength, MPa, column Annealed
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, work hardened, Heraeus datasheet
    value: 330
    unit: MPa
    scope: material
    conditions:
      temper: work hardened
      form: Pt, wire, sheet and tube
      temperature: not stated in the table
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: Mechanical properties table, row Tensile Strength, MPa, column Work Hardened
  - benchmark: elongation
    label: Elongation, annealed, Heraeus datasheet
    value: 40
    unit: '%'
    scope: material
    conditions:
      temper: annealed
      form: Pt, wire, sheet and tube
      gauge_length: not stated in the table
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: Mechanical properties table, row Elongation, %, column Annealed
  - benchmark: elongation
    label: Elongation, work hardened, Heraeus datasheet
    value: 3
    unit: '%'
    scope: material
    conditions:
      temper: work hardened
      form: Pt, wire, sheet and tube
      gauge_length: not stated in the table
    method: Value printed in a manufacturer datasheet
    status: ground
    source: heraeus-pt
    where: Mechanical properties table, row Elongation, %, column Work Hardened
  - benchmark: poisson_ratio
    label: Poisson ratio (Wikipedia infobox)
    value: 0.38
    unit: '-'
    scope: material
    conditions:
      form: element, platinum metal
      temperature: not stated in the infobox
    method: Value printed in the infobox of the Wikipedia article for platinum; no unit printed
    status: ground
    source: wikipedia-pt
    where: Infobox, Other properties, Poisson ratio
  - benchmark: temperature_coefficient_of_resistance
    label: Temperature coefficient of resistivity of platinum used in RTDs
    value: 0.0039
    unit: /°C
    scope: material
    conditions:
      form: platinum sensing element of a resistance temperature detector
      temperature_range: not stated in the report
    method: Value printed in an official accident investigation report, as the coefficient of resistivity of platinum used for RTDs
    status: ground
    note: The report calls this the temperature coefficient of resistivity (TCR), alpha = 0.0039 °C−1. Its temperature range is not stated, and the same report says the response is nearly linear over a wide range.
    source: caib
    where: Resistance-Temperature Detector (RTD) Temperature Sensors section, page 520 of Volume II
corrosion:
  - environment: Hot aqua regia
    headline: Platinum dissolves in hot aqua regia but resists hydrochloric and nitric acid alone.
    effect: The Wikipedia article says platinum is insoluble in hydrochloric and nitric acid but dissolves in hot aqua regia, forming chloroplatinic acid, H2PtCl6.
    rating: severe
    conditions:
      temperature: hot
      reagent: aqua regia (mixed hydrochloric and nitric acid)
    source: wikipedia-pt
    where: Characteristics, Chemical section
  - environment: Air at high temperature
    headline: Bulk platinum does not oxidize in air at any temperature.
    effect: The Wikipedia article says bulk platinum does not oxidize in air at any temperature, and its lead section says platinum does not corrode even at high temperatures, which is why it is classed as a noble metal.
    rating: low
    conditions:
      form: bulk platinum
      temperature: any temperature, as stated
    source: wikipedia-pt
    where: Lead section and Characteristics, Chemical section
  - environment: Hot gases on the orbiter surface
    headline: Platinum and its rhodium alloy are fairly inert towards hot gases, so reaction with them was not expected to cause corrosion.
    effect: The Columbia report says that platinum and its rhodium alloy have the same melting point of 1769 °C and that each material is fairly inert, so reactions with hot gases should not have caused unusual etching or corrosion of the thermocouples on the orbiter surfaces.
    rating: low
    conditions:
      environment: re-entry heating of the Orbiter surface, from the report's analysis
      basis: analysis in the report, not a measured corrosion rate
    source: caib
    where: Thermocouple (TC) Temperature Sensors section, page 520
risks:
  hazards:
    - text: 'PubChem GHS record for the platinum element, aggregated from ECHA C&L notifications: H228, flammable solid (10.7 % of reports), signal word Danger, pictogram GHS02 flame. The record says 410 of 504 company reports do not meet GHS criteria.'
      ghs:
        - H228
      source: pubchem-pt
      where: Hazards Identification, GHS Classification
    - text: The same PubChem record lists H315 (skin irritation), H319 (serious eye irritation), H334 (may cause allergy or asthma symptoms or breathing difficulties if inhaled) and H335 (may cause respiratory irritation) from 94 of 504 company reports that gave hazard codes.
      ghs:
        - H315
        - H319
        - H334
        - H335
      source: pubchem-pt
      where: Hazards Identification, GHS Classification, ECHA C&L Notifications Summary
  failure_risks:
    - mode: Mechanical failure of a thermocouple
      trigger: Mechanical stress on the welds, wires or splices, or leads pinched together so they short
      consequence: The report says failures would most likely arise from broken welds or wires, or from shorting that moves the sensing point. It gives no failure rate.
      severity: low
      source: caib
      where: Thermocouple (TC) Temperature Sensors section, page 520
    - mode: Debonding of a platinum sensor from its surface
      trigger: Adhesive release of the RTD sensor from the mounted component
      consequence: The report says failure of the sensor would most likely be debonding or adhesive release, rather than melting of the metal, which melts at 1769 °C.
      severity: low
      source: caib
      where: Resistance-Temperature Detector (RTD) Temperature Sensors section, page 519
  side_effects:
    - text: Platinum is dense at 21.45 g/cm3, so parts are heavy for their volume.
      affects: Mass of a sensor, contact or crucible
      source: heraeus-pt
      where: General information table, row Density
  handling:
    - text: PubChem lists the precautionary codes P210, P240, P241, P280 and P370+P378 for the platinum element record, with the H228 flammable-solid classification.
      source: pubchem-pt
      where: Hazards Identification, Precautionary Statement Codes
    - text: The Heraeus datasheet gives the product forms as wire, sheet and tube, and says the metal is ductile and can be roll clad, formed and machined.
      source: heraeus-pt
      where: Forming Processes table
  mitigations: []
uses:
  - application: thermal-control
    device: Platinum resistance thermometers (RTDs) on the Space Shuttle Orbiter
    example: Each sensor is a chemically pure platinum element bonded to an insulating substrate, with a nominal resistance of 100 Ω at 0 °C and an operating range of −320 °F to +500 °F, or up to +2000 °F depending on the dash number. The report estimates the inherent accuracy of the Shuttle Pt RTD systems at 2 to 3 °F.
    source: caib
    where: Resistance-Temperature Detector (RTD) Temperature Sensors section, page 519
  - application: thermal-control
    device: Platinum-rhodium thermocouples (Type R) on the Orbiter skin and heat tiles
    example: Type II thermocouples are platinum alloy (87 % Pt, 13 % Rh) against platinum, rated from −65 °F to +3000 °F, and are used on the lower outer skin of the wings and fuselage and on the outer surface of the heat tiles.
    source: caib
    where: Thermocouple (TC) Temperature Sensors section, pages 519 and 520
  - application: propulsion-and-tanks
    device: Butt-welded platinum-platinum 10 % rhodium thermocouples in a liquid-rocket injector test
    example: A NASA contractor report used 0.010 and 0.020 inch platinum-platinum 10 % rhodium thermocouples inserted through the injector face of a heptane and liquid oxygen engine at 300 psia. The average gas temperature was between 3100 and 3500 °F (1700 and 1950 °C).
    source: ntrs-cr1211
    where: Abstract (item 16) and the experimental section
  - application: electronics-and-chips
    device: Electronic components
    example: The USGS lists computer hard disks, hybridized integrated circuits and multilayer ceramic capacitors among the electronic uses of platinum-group metals.
    source: usgs-mcs2026-pgm
    where: Domestic Production and Use paragraph, PGM chapter
supply:
  - subject: Platinum mine production (United States net import reliance 89 % of apparent consumption in 2025e)
    producers:
      - country: South Africa
        share_percent: 70.6
        year: 2025
      - country: Russia
        share_percent: 11.8
        year: 2025
      - country: Zimbabwe
        share_percent: 10.6
        year: 2025
      - country: Canada
        share_percent: 2.9
        year: 2025
      - country: United States
        share_percent: 1.1
        year: 2025
    critical_lists:
      - list: USGS Final 2025 List of Critical Minerals (platinum listed, platinum-group metals chapter)
        listed: true
    recycling: 'USGS: about 140,000 kg of palladium and platinum were recovered globally from new and old scrap in 2025, including 8,600 kg of platinum recovered from automobile catalytic converters in the United States.'
    substitutes:
      - 'USGS: palladium can be used in place of platinum in most gasoline-engine catalytic converters, and about 25 % of palladium can routinely be substituted for platinum in diesel catalytic converters.'
    source: usgs-mcs2026-pgm
    where: 'World Mine Production and Reserves table (platinum 2025e: South Africa 120,000 kg, Russia 20,000 kg, Zimbabwe 18,000 kg, Canada 5,000 kg, United States 1,800 kg, world total 170,000 kg). Shares are calculated by Space Mushroom from those kilogram values. Net import reliance table; Recycling; Substitutes; Critical minerals table footnote 3.'
documents:
  - title: Heraeus Precious Metals, Pt datasheet (Platinum, general information and physical and mechanical properties), status 09/2021
    type: datasheet
    url: https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Pt_Datasheet_EN_(Heraeus_Precious_Metals).pdf
    year: 2021
  - title: 'Wikipedia: Platinum'
    type: database
    url: https://en.wikipedia.org/wiki/Platinum
    year: 2026
  - title: PubChem compound record for platinum (CID 23939), GHS classification and CAS number
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23939/JSON
  - title: USGS Mineral Commodity Summaries 2026, Platinum-Group Metals chapter
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026.pdf
    year: 2026
  - title: Columbia Accident Investigation Board Report, Volume II, October 2003, instrumentation section (RTD and thermocouple sensors)
    type: report
    url: https://govinfo.library.unt.edu/caib/news/report/pdf/vol2/part19.pdf
    year: 2003
  - title: Boylan and O'Hara, Gas velocity and temperature near a liquid rocket injector face, NASA CR-1211, Tulane University
    type: report
    url: https://ntrs.nasa.gov/api/citations/19730011577/downloads/19730011577.pdf
  - title: VEM, platinum material page (physical properties, chemical properties, purity guide)
    type: datasheet
    url: https://www.vem-co.com/material-docs/platinum/
  - title: ASTM B561-23, Standard Specification for Refined Platinum (page summary of the grades and scope)
    type: standard
    url: http://www.technickenormy.cz/astm-b0561-23-standard-specification-for-refined-platinum
gaps:
  - 'UNS P04995 for the 99.95 grade is not entered as a designation: the page that prints the grade shows it as PO4995 (letter O), and verify-values would not find P04995 in it. The 99.99 grade has no UNS number in the source.'
  - No EN, DIN, W.Nr., JIS or AISI number for platinum was found in a page read in this run. The EN and W.Nr. searches returned no platinum code.
  - Crustal abundance, seawater, and the share of platinum in lunar or Martian regolith were not looked up.
  - No NASA outgassing test result (total mass loss or collected volatile condensable material) for platinum was found.
  - Atomic oxygen erosion yield, cold welding and radiation effects for platinum were not looked up.
  - The Johnson Matthey physical-property article (1984, thermophysical data) and the Johnson Matthey PGM database were found by search, but their tables were not readable, so they are not used.
  - The Pt-Rh thermocouple drift value (a NASA Lewis brief on about -2.8 K after 3700 hours at 1530 K) was seen only in a search snippet and was not opened, so it is not recorded.
  - The platinum RTD flight heritage on ESA satellites and the TE Connectivity claim of more than 20 years of flight heritage are vendor statements, not read in an agency document, so they are not recorded.
  - The Wikipedia infobox does not state the temperature for the Young's modulus, shear modulus, specific heat, Brinell hardness, or Poisson ratio, so those rows have no temperature condition.
  - The Heraeus datasheet gives no temperature for density, melting point, thermal conductivity, Young's modulus, or the strength values.
  - The 2025 world totals are given for platinum only; the USGS report's 2025 reserve figures are printed in a column that is misaligned in the text extraction, so reserves are not recorded.
  - The 2024 platinum price and the 2025 platinum price (USGS, dollars per troy ounce) are not recorded as properties.
  - Platinum powder hazards from a supplier SDS (for example Sigma-Aldrich product 327476) were not read; the hazards here come from the PubChem record only.
  - The media section of the LFP reference is not added, since no image or figure source was located for this profile.
  - Canonical benchmark names were not checked for shear_modulus, vickers_hardness, hardness_brinell, poisson_ratio and temperature_coefficient_of_resistance, which may need to be added to spores/property-canon.yaml.
  - The type is set to precious-metals, as gold and silver use it, rather than heavy-metals; platinum is a precious metal in the taxonomy.
sources:
  heraeus-pt:
    title: Pt Datasheet EN, Platinum (Heraeus Precious Metals GmbH & Co. KG), status 09/2021
    url: https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Pt_Datasheet_EN_(Heraeus_Precious_Metals).pdf
    year: 2021
    kind: datasheet
    license: Manufacturer datasheet (cited, not reproduced)
  wikipedia-pt:
    title: Platinum (Wikipedia, infobox and Characteristics sections)
    url: https://en.wikipedia.org/wiki/Platinum
    year: 2026
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  pubchem-pt:
    title: PubChem compound record, Platinum (CID 23939), GHS classification and CAS number
    id: CID 23939, CAS 7440-06-4
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23939/JSON
    kind: database
    license: PubChem (NCBI), public domain; sections attributed to ECHA and others
  usgs-mcs2026-pgm:
    title: Mineral Commodity Summaries 2026, Platinum-Group Metals chapter (U.S. Geological Survey, February 2026)
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  caib:
    title: Columbia Accident Investigation Board Report, Volume II, instrumentation section (October 2003)
    url: https://govinfo.library.unt.edu/caib/news/report/pdf/vol2/part19.pdf
    year: 2003
    kind: report
    license: public domain (NASA report)
  ntrs-cr1211:
    title: Gas Velocity and Temperature Near a Liquid Rocket Injector Face, NASA CR-1211 (Boylan and O'Hara, Tulane University)
    id: NTRS 19730011577
    url: https://ntrs.nasa.gov/api/citations/19730011577/downloads/19730011577.pdf
    kind: report
    license: public domain (NASA)
  vem-pt:
    title: 'VEM, Platinum (Pt) material page: properties and purity data'
    url: https://www.vem-co.com/material-docs/platinum/
    kind: datasheet
    license: Supplier web page (cited, not reproduced)
  astm-b561:
    title: ASTM B561-23, Standard Specification for Refined Platinum (page summary of the grades and scope)
    url: http://www.technickenormy.cz/astm-b0561-23-standard-specification-for-refined-platinum
    kind: standard
    license: Summary page for a standard (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 27
  unreachable: 2
  caveats: 6
  note: 'Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable: the ASTM standard itself (only a summary page was read), and the American Elements and Sigma-Aldrich SDS pages (403 or not opened). Caveats: the Heraeus datasheet gives no temperatures; Wikipedia values are secondary and some lack conditions; the flight use is limited to the Shuttle sensors and one NASA contractor ground test; the supply shares are calculated from kilogram values; the UNS number is printed in the source with a letter O and is not entered; the TCR value has no stated temperature range.'
story:
  risk_groups:
    - title: For people
      lead: 'The hazard record for the platinum element is mixed: most of the notifications report no GHS hazard, and a minority report flammability and respiratory sensitisation.'
      level: 1
      verdict: Mixed notifications
      points:
        - label: Platinum as a substance
          line: Of 504 company reports to the European chemicals agency, 410 said platinum does not meet GHS criteria. Among the reports that gave codes, H228 (flammable solid, 10.7 %) is the classification shown in the PubChem summary, with the signal word Danger.
        - label: Respiratory sensitisation
          line: PubChem also lists H334 (may cause allergy or asthma symptoms or breathing difficulties if inhaled) from 94 of 504 reports that gave hazard codes. This is a reason to handle fine platinum dust with care.
    - title: If it fails
      lead: These are failure routes found in the sources. None of them is a measured failure rate.
      points:
        - label: Thermocouple wiring
          line: The Columbia report says a thermocouple would most likely fail from broken welds, wires or splices, or from leads shorting together. It gives no failure rate.
        - label: Sensor debonding
          line: The same report says an RTD would most likely fail by debonding from its surface, not by melting of the metal, which melts at 1769 °C.
        - label: Aqua regia
          line: Platinum dissolves in hot aqua regia. That is a chemical failure route for any platinum part in a process containing it.
    - title: Handling and storage
      points:
        - label: Keep the temper in mind
          line: The Heraeus datasheet gives 70 MPa yield strength annealed and 290 MPa work hardened, so the temper changes the design strength a lot.
        - label: Fine forms
          line: PubChem gives the element H228 (flammable solid) and precautionary codes P210 and P240, so keep fine forms away from heat and ignition sources.
  why: Platinum is a dense, ductile precious metal that resists oxidation and dissolves only in hot aqua regia. The Heraeus datasheet gives a density of 21.45 g/cm3, a melting point of 1769 °C and a thermal conductivity of 74 W/(m·K) at 20 °C. The resistance of platinum changes linearly and stably with temperature, with a temperature coefficient of resistivity of 0.0039 per °C in the Columbia report, which is why it is used in resistance thermometers. The Space Shuttle Orbiter carried platinum RTDs and platinum-rhodium thermocouples to measure temperatures on its skin and heat tiles. A NASA contractor report used platinum-rhodium thermocouples to measure gas temperatures near a liquid-rocket injector face.
  uses:
    - where: Shuttle temperature sensors
      line: The Space Shuttle Orbiter used platinum resistance thermometers, with a nominal resistance of 100 Ω at 0 °C and an estimated accuracy of 2 to 3 °F. Its platinum-rhodium thermocouples were used on the wing and fuselage skin and on the outer surface of the heat tiles.
    - where: Rocket injector test
      line: Butt-welded platinum-platinum 10 % rhodium thermocouples were pushed through the injector face of a liquid-rocket engine and measured average gas temperatures of 3100 to 3500 °F (1700 to 1950 °C).
    - where: Electronics and catalysts
      line: The USGS lists electronic uses such as hard disks, integrated circuits and multilayer ceramic capacitors, and the leading use of platinum-group metals is in catalytic converters.
  can_do:
    - label: Measure temperature
      value: 0.0039 per °C
      benchmark: temperature_coefficient_of_resistance
      line: The resistance of a platinum sensing element rises by a coefficient of 0.0039 per °C, and the RTD is linear and stable over a wide range. The temperature range of that coefficient is not stated.
    - label: Carry heat
      value: 74 W/(m·K)
      benchmark: thermal_conductivity
      line: Thermal conductivity is 74 W/(m·K) at 20 °C in the Heraeus datasheet, and 71.6 W/(m·K) in the Wikipedia infobox with no temperature stated.
    - label: Weight
      value: 21.45 g/cm3
      benchmark: density
      line: Density is 21.45 g/cm3 in the Heraeus datasheet and 21.452 g/cm3 at 20 °C in the Wikipedia infobox.
    - label: Melting
      value: 1769 °C
      benchmark: melting_point
      line: The Heraeus datasheet gives a melting point of 1769 °C. The Wikipedia infobox gives 1768.3 °C, and the Columbia report uses 1769 °C.
    - label: Strength when annealed
      value: 70 MPa yield
      benchmark: yield_strength
      line: Annealed platinum has a yield strength of 70 MPa and a tensile strength of 150 MPa, and stretches 40 % before breaking.
    - label: Strength when work hardened
      value: 290 MPa yield
      benchmark: yield_strength
      line: Work-hardened platinum has a yield strength of 290 MPa and a tensile strength of 330 MPa, but stretches only 3 % before breaking.
  compare: Platinum is much denser than copper and conducts heat less well than copper, but it resists corrosion and oxidation far better. The table rows show the same quantity for both metals, but they come from different sources and grades, so read them as examples, not as a ranking.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Thermal conductivity
      benchmark: thermal_conductivity
    - label: Thermal expansion
      benchmark: cte
  handling:
    - Specify the temper, since annealed and work-hardened platinum differ by a factor of about four in yield strength (70 and 290 MPa).
    - Keep fine platinum forms away from heat and ignition sources, since PubChem classes the element as a flammable solid (H228).
    - Keep platinum parts out of hot aqua regia and other strong oxidising chloride mixtures, which dissolve the metal.
  good_for:
    - 'Sensing temperature: the coefficient of 0.0039 per °C in an RTD element, as used on the Space Shuttle Orbiter.'
    - 'Corrosion-resistant contacts and high-temperature thermocouples: platinum does not oxidize in air at any temperature, according to the Wikipedia article.'
    - 'Recycling: about 140,000 kg of palladium and platinum was recovered from scrap in 2025, according to the USGS.'
  watch_out:
    - 'Soft platinum is weak: 70 MPa yield in the annealed temper.'
    - 'Platinum is expensive and supply is concentrated: South Africa produced about 70.6 % of the 2025 world platinum mine output, and the United States imports 89 % of its apparent consumption.'
    - Hot aqua regia dissolves platinum, so acid-cleaning and chloride processes need checking.
    - No NASA outgassing, atomic-oxygen erosion or cold-welding result was found for platinum in this profile.
  verdict: Platinum is a dense, ductile precious metal that resists oxidation and has a stable temperature coefficient of resistance, which is why it is used in thermometers and thermocouples. It is soft when annealed, heavy, expensive, and dissolves in hot aqua regia. The Shuttle sensors and a rocket-injector test are the flight and near-flight uses found in the sources. This profile lacks NASA outgassing, erosion and cold-welding numbers.
  recipe:
    line: Platinum is a single-element metal (Pt) with a face-centred cubic crystal structure (Wikipedia; VEM). The Wikipedia article says it is a noble metal with six naturally occurring isotopes, the most abundant being 195Pt. The USGS summary places platinum in the platinum-group metals chapter, with mine production in South Africa, Russia and Zimbabwe, and says it is refined and recovered from scrap, including catalytic converters.
    parts:
      - name: Platinum
        symbol: Pt
        atoms: 1
        atomic_weight: 195.08
        role: The whole material. The VEM page gives atomic number 78 and atomic weight 195.08.