{
  "spore": "profile",
  "id": "platinum-iridium",
  "spore_version": "0.2",
  "family": "precious-metals",
  "name": "Platinum-iridium alloy",
  "abbreviation": "Pt-Ir",
  "role": "standards, electrodes and thermocouple wire",
  "category": "metals",
  "type": "precious-metals",
  "summary": "Platinum-iridium is a ductile precious-metal alloy, most often 90 % platinum and 10 % iridium (Pt-10Ir). The Heraeus datasheet for PtIr10 gives a density of 21.54 g/cm3 and a melting range of 1790 to 1800 °C. The harder PtIr20 grade has a density of 21.7 g/cm3 and a melting range of 1830 to 1855 °C. The international kilogram prototype is made of 90 % platinum and 10 % iridium, and the 1985 NIST paper gives a density of 21.55 g/cm3 for the prototypes. Heraeus lists PtIr10 for thermocouples, electrodes and spark plug electrodes, and PtIr20 for medical wire and probe needles. No space-electrode source was found in this run.\n",
  "best_for": "Reference artefacts and electrodes that need a dense, hard, stable metal. The kilogram and metre prototypes were made of it, and the alloy is harder than pure platinum.",
  "weakest_at": "Heavy for its size (21.54 g/cm3 for PtIr10) and soft when annealed (105 HV for PtIr10)",
  "identity": {
    "formula": "Pt-10Ir, 90 % platinum and 10 % iridium by mass (the kilogram prototype alloy); Pt-20Ir is the Heraeus PtIr20 grade",
    "designations": [],
    "source": "nist-v90-4",
    "where": "Section 1 (Introduction), page 263: the IPK is made of an alloy of 90% platinum and 10% iridium. Heraeus designations PtIr10 (Hera 173) and PtIr20 (Hera 174)."
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "thermal-control",
      "propulsion-and-tanks",
      "electronics-and-chips"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, PtIr10 (Heraeus Hera 173)",
      "value": 21.54,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "PtIr10 wire and sheet (Heraeus product forms)",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "General information table, row Density, g/cm³",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, PtIr20 (Heraeus Hera 174)",
      "value": 21.7,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "PtIr20 wire (Heraeus product forms)",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "General information table, row Density, g/cm³",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density of the national prototype kilograms (NIST paper)",
      "value": 21.55,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "platinum-iridium prototype kilograms (90 % Pt, 10 % Ir)",
        "temperature": "not stated in the text"
      },
      "method": "Value printed in a 1985 NIST journal paper on the prototype kilogram",
      "status": "ground",
      "source": "nist-v90-4",
      "where": "Section 1 (Introduction), page 263, paragraph on the nichrome working standards",
      "source_detail": {
        "title": "Davis, Recalibration of the U.S. National Prototype Kilogram, Journal of Research of NBS, volume 90, number 4 (1985)",
        "url": "https://nvlpubs.nist.gov/nistpubs/jres/090/4/V90-4.pdf",
        "year": 1985,
        "kind": "paper",
        "license": "public domain (NIST)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting range, PtIr10 (Heraeus Hera 173)",
      "value": 1790,
      "value_high": 1800,
      "bound": "range",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "PtIr10 wire and sheet",
        "pressure": "not stated"
      },
      "method": "Range printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "General information table, row Melting Range, °C",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting range, PtIr20 (Heraeus Hera 174)",
      "value": 1830,
      "value_high": 1855,
      "bound": "range",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "PtIr20 wire",
        "pressure": "not stated"
      },
      "method": "Range printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "General information table, row Melting Range, °C",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, PtIr10 (Heraeus Hera 173)",
      "value": 202.3,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "PtIr10 wire and sheet",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, row Young's Modulus, GPa",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, PtIr20 (Heraeus Hera 174)",
      "value": 255,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "PtIr20 wire",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, row Young's Modulus, GPa",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "shear_modulus",
      "label": "Modulus of rigidity, PtIr10 (Heraeus Hera 173)",
      "value": 73.4,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "PtIr10 wire and sheet",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, row Modulus of Rigidity, GPa",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "shear_modulus",
      "label": "Modulus of rigidity, PtIr20 (Heraeus Hera 174)",
      "value": 86,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "PtIr20 wire",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, row Modulus of Rigidity, GPa",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "electrical_conductivity",
      "label": "Electrical conductivity range, PtIr10 (Heraeus Hera 173)",
      "value": 6.83,
      "value_high": 7.02,
      "bound": "range",
      "unit": "% IACS",
      "scope": "material",
      "conditions": {
        "form": "PtIr10 wire and sheet",
        "temperature": "not stated in the table"
      },
      "method": "Minimum and maximum printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, rows Conductivity, min., % IACS and Conductivity, max., % IACS",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "electrical_conductivity",
      "label": "Electrical conductivity range, PtIr20 (Heraeus Hera 174)",
      "value": 5.38,
      "value_high": 5.55,
      "bound": "range",
      "unit": "% IACS",
      "scope": "material",
      "conditions": {
        "form": "PtIr20 wire",
        "temperature": "not stated in the table"
      },
      "method": "Minimum and maximum printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, rows Conductivity, min., % IACS and Conductivity, max., % IACS",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "vickers_hardness",
      "label": "Hardness HV, PtIr10 annealed (Heraeus Hera 173)",
      "value": 105,
      "bound": "exact",
      "unit": "HV",
      "scope": "material",
      "conditions": {
        "temper": "annealed",
        "form": "PtIr10 wire and sheet"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, row Hardness, HV, column Annealed",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "vickers_hardness",
      "label": "Hardness HV, PtIr10 work hardened (Heraeus Hera 173)",
      "value": 215,
      "bound": "exact",
      "unit": "HV",
      "scope": "material",
      "conditions": {
        "temper": "work hardened",
        "form": "PtIr10 wire and sheet"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, row Hardness, HV, column Work Hardened",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "vickers_hardness",
      "label": "Hardness HV, PtIr20 annealed (Heraeus Hera 174)",
      "value": 190,
      "bound": "exact",
      "unit": "HV",
      "scope": "material",
      "conditions": {
        "temper": "annealed",
        "form": "PtIr20 wire"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, row Hardness, HV, column Annealed",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "vickers_hardness",
      "label": "Hardness HV, PtIr20 work hardened (Heraeus Hera 174)",
      "value": 300,
      "bound": "exact",
      "unit": "HV",
      "scope": "material",
      "conditions": {
        "temper": "work hardened",
        "form": "PtIr20 wire"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, row Hardness, HV, column Work Hardened",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength, PtIr10 annealed (Heraeus Hera 173)",
      "value": 220,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "annealed",
        "form": "PtIr10 wire and sheet",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, row Yield Strength, MPa, column Annealed",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength, PtIr10 work hardened (Heraeus Hera 173)",
      "value": 630,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "work hardened",
        "form": "PtIr10 wire and sheet",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, row Yield Strength, MPa, column Work Hardened",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength, PtIr20 annealed (Heraeus Hera 174)",
      "value": 380,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "annealed",
        "form": "PtIr20 wire",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, row Yield Strength, MPa, column Annealed",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength, PtIr20 work hardened (Heraeus Hera 174)",
      "value": 920,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "work hardened",
        "form": "PtIr20 wire",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, row Yield Strength, MPa, column Work Hardened",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, PtIr10 annealed (Heraeus Hera 173)",
      "value": 340,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "annealed",
        "form": "PtIr10 wire and sheet",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, row Tensile Strength, MPa, column Annealed",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, PtIr10 work hardened (Heraeus Hera 173)",
      "value": 650,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "work hardened",
        "form": "PtIr10 wire and sheet",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, row Tensile Strength, MPa, column Work Hardened",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, PtIr20 annealed (Heraeus Hera 174)",
      "value": 570,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "annealed",
        "form": "PtIr20 wire",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, row Tensile Strength, MPa, column Annealed",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, PtIr20 work hardened (Heraeus Hera 174)",
      "value": 940,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temper": "work hardened",
        "form": "PtIr20 wire",
        "temperature": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, row Tensile Strength, MPa, column Work Hardened",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation, PtIr10 annealed (Heraeus Hera 173)",
      "value": 32,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "temper": "annealed",
        "form": "PtIr10 wire and sheet",
        "gauge_length": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, row Elongation, %, column Annealed",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation, PtIr10 work hardened (Heraeus Hera 173)",
      "value": 2,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "temper": "work hardened",
        "form": "PtIr10 wire and sheet",
        "gauge_length": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt10ir",
      "where": "Physical properties table, row Elongation, %, column Work Hardened",
      "source_detail": {
        "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation, PtIr20 annealed (Heraeus Hera 174)",
      "value": 21,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "temper": "annealed",
        "form": "PtIr20 wire",
        "gauge_length": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, row Elongation, %, column Annealed",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation, PtIr20 work hardened (Heraeus Hera 174)",
      "value": 2,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "temper": "work hardened",
        "form": "PtIr20 wire",
        "gauge_length": "not stated in the table"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "heraeus-pt20ir",
      "where": "Physical properties table, row Elongation, %, column Work Hardened",
      "source_detail": {
        "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
        "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
        "year": 2021,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "charge_injection_capacity",
      "label": "Charge injection of electrodeposited PtIr on carbon fibre",
      "value": 1.25,
      "bound": "exact",
      "unit": "mC/cm2",
      "scope": "material",
      "conditions": {
        "form": "electrodeposited PtIr coating on carbon fibre microelectrodes (not a bulk alloy)",
        "pulse": "0.5 ms pulses",
        "electrolyte": "1x PBS (0.01 M phosphate buffered saline)"
      },
      "method": "Value printed in a 2021 open-access paper, section 4; the paper calls it the highest density tested",
      "status": "ground",
      "note": "Benchmark name is not in the canonical file; it is a coating result on carbon fibre, not a bulk-alloy value.",
      "source": "frontiers-ptir",
      "where": "Section 4 (Discussion or conclusion), charge injection sentence",
      "source_detail": {
        "title": "Electrodeposited Platinum Iridium Enables Microstimulation With Carbon Fiber Electrodes (Frontiers in Nanotechnology, 2021)",
        "id": "doi:10.3389/fnano.2021.782883",
        "url": "https://www.frontiersin.org/journals/nanotechnology/articles/10.3389/fnano.2021.782883/full",
        "year": 2021,
        "kind": "paper",
        "license": "open access (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Storage and handling of the kilogram prototype (airborne pollutants and mercury vapour)",
      "headline": "The kilogram prototype loses about 50 μg against its copies over a century, mostly from contamination.",
      "effect": "The Wikipedia article says the IPK lost perhaps 50 μg relative to its official copies over the last century. Cleaning removes between 5 and 60 μg of contamination, and the article links the drift to mercury absorbed near mercury-based instruments.",
      "rating": "low",
      "conditions": {
        "basis": "mass drift relative to official copies, not a corrosion rate",
        "cleaning": "rubbing with ether and ethanol, then steam (as the article describes)"
      },
      "source": "wikipedia-ipk",
      "where": "Stability of the IPK section and cleaning passage"
    },
    {
      "environment": "Repeated electrical stimulation in phosphate-buffered saline (PtIr coating on carbon fibre)",
      "headline": "No coating loss or delamination was seen after stimulation tests.",
      "effect": "The paper says that in all stimulation experiments, SEM inspection found no coating loss or delamination. It did not measure corrosion or dissolution of Pt or Ir.",
      "rating": "low",
      "conditions": {
        "electrolyte": "1x PBS",
        "basis": "visual and SEM inspection after pulse tests; no mass loss or dissolution measured"
      },
      "source": "frontiers-ptir",
      "where": "Section 4 (stability finding)"
    },
    {
      "environment": "General use, as listed by the manufacturer",
      "headline": "Heraeus lists PtIr20 as corrosion resistant, with no test conditions.",
      "effect": "The Hera 174 datasheet lists PtIr20 under chemical properties as corrosion resistant. It gives no environment, test method or corrosion rate.",
      "rating": "low",
      "conditions": {
        "basis": "qualitative datasheet statement only"
      },
      "source": "heraeus-pt20ir",
      "where": "Chemical properties section"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem iridium record (CID 23924): 36.9 % of company reports (92 of 249) do not meet GHS criteria. Notified codes are H228 (18.1 %, flammable solid), H319 (20.1 %, serious eye irritation) and H413 (41.8 %, long-lasting harmful effects to aquatic life), with signal word Danger.",
        "ghs": [
          "H228",
          "H319",
          "H413"
        ],
        "source": "pubchem-ir",
        "where": "Safety and Hazards, GHS Classification, ECHA C&L Notifications Summary"
      },
      {
        "text": "PubChem platinum record (CID 23939): 81.3 % of company reports (410 of 504) do not meet GHS criteria. H228 (10.7 %, flammable solid) is shown, with signal word Danger.",
        "ghs": [
          "H228"
        ],
        "source": "pubchem-pt",
        "where": "Safety and Hazards, GHS Classification, ECHA C&L Notifications Summary"
      },
      {
        "text": "The same platinum record lists H315, H319, H334 and H335 from 94 of 504 company reports that gave hazard codes. H334 is respiratory sensitisation.",
        "ghs": [
          "H315",
          "H319",
          "H334",
          "H335"
        ],
        "source": "pubchem-pt",
        "where": "Safety and Hazards, GHS Classification, second notification block"
      }
    ],
    "failure_risks": [
      {
        "mode": "Cracking of an electrodeposited PtIr film at a microelectrode tip",
        "trigger": "Preliminary in vivo stimulation of visual cortex and spinal cord in the 2021 study",
        "consequence": "The paper reports a crack in the PtIr film near the tip after in vivo stimulation, and says it is more likely from deposition, handling or SEM preparation. It is a single preliminary observation.",
        "severity": "low",
        "source": "frontiers-ptir",
        "where": "Section 3.3"
      }
    ],
    "side_effects": [
      {
        "text": "PtIr10 has a density of 21.54 g/cm3, so parts are heavy for their volume.",
        "affects": "Mass of an electrode, contact or prototype",
        "source": "heraeus-pt10ir",
        "where": "General information table, row Density"
      }
    ],
    "handling": [
      {
        "text": "PubChem precautionary codes for the iridium element record include P210, P240, P241, P280 and P370+P378 among a longer list, with the H228 flammable-solid classification.",
        "source": "pubchem-ir",
        "where": "Hazards Identification, Precautionary Statement Codes"
      },
      {
        "text": "The Hera 174 datasheet lists PtIr20 as formable, machinable and able to be roll clad.",
        "source": "heraeus-pt20ir",
        "where": "Forming Process row"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "thermal-control",
      "device": "Thermocouples and electrodes (PtIr10 product listing)",
      "example": "Heraeus lists PtIr10 for thermocouples, electrodes and spark plug electrodes, in wire and sheet form.",
      "source": "heraeus-pt10ir",
      "where": "General information table, row Applications"
    },
    {
      "application": "propulsion-and-tanks",
      "device": "Spark plug electrodes",
      "example": "Heraeus lists both PtIr10 and PtIr20 for spark plug electrodes. The PtIr20 listing also includes contacts and sliding contacts.",
      "source": "heraeus-pt20ir",
      "where": "General information table, row Applications"
    },
    {
      "application": "electronics-and-chips",
      "device": "Medical wire and probe needles",
      "example": "Heraeus lists PtIr20 for medical wire and probe needles, as well as contacts and electrodes.",
      "source": "heraeus-pt20ir",
      "where": "General information table, row Applications"
    },
    {
      "application": "electronics-and-chips",
      "device": "Microelectrodes for neural stimulation (research, preliminary)",
      "example": "A 2021 study electrodeposited PtIr on carbon fibre microelectrodes and tested them for visual cortex and spinal cord stimulation. The authors call the in vivo work preliminary.",
      "source": "frontiers-ptir",
      "where": "Introduction and Section 4"
    }
  ],
  "supply": [
    {
      "subject": "Platinum (world mine production and recycling, used for the Pt content)",
      "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-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.",
      "substitutes": [],
      "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. Recycling paragraph, PGM chapter, page 145."
    },
    {
      "subject": "Iridium (United States imports and price; no world mine production in the chapter)",
      "abundance": "United States imports of iridium were 2,200 kg in 2025e. The 2025e price was 4,400 dollars per troy ounce.",
      "producers": [],
      "critical_lists": [
        {
          "list": "USGS MCS 2026 footnote: iridium is among the critical minerals published in the Federal Register on November 7, 2025, but is not shown in the production table",
          "listed": true
        }
      ],
      "recycling": "Not read in this run.",
      "substitutes": [],
      "source": "usgs-mcs2026-pgm",
      "where": "Salient Statistics table (imports for consumption, iridium 2025e); Price table, dollars per troy ounce; footnote on critical minerals in the Mineral Commodity Summaries table"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Heraeus Precious Metals, PtIr10 (Hera 173) datasheet, status 11/2021",
      "type": "datasheet",
      "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
      "year": 2021
    },
    {
      "title": "Heraeus Precious Metals, PtIr20 (Hera 174) datasheet, status 09/2021",
      "type": "datasheet",
      "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
      "year": 2021
    },
    {
      "title": "Davis, Recalibration of the U.S. National Prototype Kilogram, J. Res. NBS 90(4), 1985",
      "type": "paper",
      "url": "https://nvlpubs.nist.gov/nistpubs/jres/090/4/V90-4.pdf",
      "year": 1985
    },
    {
      "title": "Wikipedia: International Prototype of the Kilogram",
      "type": "database",
      "url": "https://en.wikipedia.org/wiki/International_Prototype_of_the_Kilogram",
      "year": 2026
    },
    {
      "title": "Wikipedia: Mètre des Archives (metre prototype)",
      "type": "database",
      "url": "https://en.wikipedia.org/wiki/M%C3%A8tre_des_Archives",
      "year": 2026
    },
    {
      "title": "PubChem compound record, Iridium (CID 23924), GHS classification",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23924/JSON",
      "year": 2026
    },
    {
      "title": "PubChem compound record, Platinum (CID 23939), GHS classification",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23939/JSON",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026, Platinum-Group Metals chapter",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026.pdf",
      "year": 2026
    },
    {
      "title": "della Valle et al., Electrodeposited Platinum Iridium Enables Microstimulation With Carbon Fiber Electrodes, Frontiers in Nanotechnology, 2021",
      "type": "paper",
      "url": "https://www.frontiersin.org/journals/nanotechnology/articles/10.3389/fnano.2021.782883/full",
      "year": 2021
    }
  ],
  "gaps": [
    "No space-electrode source was found. The searches returned an Aerospace Corporation screen-embrittlement report (not read) and iridium and platinum alloys used to encapsulate radioisotope fuel pellets, which is not an electrode use and was not read in full.",
    "No thermal conductivity, coefficient of thermal expansion, specific heat or Poisson ratio for Pt-Ir was found in a page read in this run.",
    "No UNS, EN, DIN, JIS or ASTM designation for PtIr10 or PtIr20 was printed in a page read in this run. ASTM B684 was named only in an aggregator snippet and is not recorded.",
    "The Heraeus datasheets give no temperature or test method for any property, so conditions are marked as not stated.",
    "The metre bar density and hardness are not printed in the Wikipedia article read in this run, which gives only the composition, the X-shaped section, 16 mm by 16 mm by 102 cm dimensions and the hardness reason.",
    "No application in the fixed application list fits metrology, so the kilogram and metre standards are described in the story but not in uses.",
    "No pacing-lead or implant corrosion test on bulk Pt-Ir was read in this run. The corrosion entries are a datasheet statement, a prototype mass-drift figure and a coating study.",
    "Hazard records are for the platinum and iridium elements, not for the alloy. No Pt-Ir alloy safety data sheet was read.",
    "Iridium world mine production is not in the USGS PGM chapter, so the iridium supply entry gives United States imports and price only.",
    "The charge injection benchmark and the hardness and electrical conductivity names are not in the canonical file. They are used as short snake_case or existing names and need adding to spores/property-canon.yaml.",
    "No media entry: no image of a Pt-Ir prototype, electrode or datasheet figure was checked for licence in this run, so the media section is left out.",
    "Third-party sites give different PtIr10 tensile and hardness ranges. Those were not recorded; only the Heraeus datasheet values are used."
  ],
  "story": {
    "why": "Platinum-iridium is used where a dense, hard and stable metal is needed. The kilogram prototype is made of 90 % platinum and 10 % iridium, and the metre bar was made from a similar alloy by the BIPM with Johnson Matthey. The Wikipedia article says the alloy is harder than pure platinum, and Heraeus lists PtIr10 for thermocouples, electrodes and spark plug electrodes. PtIr20 is listed for medical wire and probe needles. In a 2021 study, electrodeposited PtIr on carbon fibre stimulated tissue in a preliminary test.",
    "uses": [
      {
        "where": "Thermocouples and spark plugs",
        "line": "Heraeus lists PtIr10 for thermocouples, electrodes and spark plug electrodes, in wire and sheet form."
      },
      {
        "where": "Medical wire and probe needles",
        "line": "Heraeus lists PtIr20 for medical wire and probe needles, as well as contacts and electrodes."
      },
      {
        "where": "Microelectrodes (research, preliminary)",
        "line": "A 2021 study electrodeposited PtIr on carbon fibre microelectrodes and tested them for visual cortex and spinal cord stimulation. The authors call the in vivo work preliminary."
      }
    ],
    "can_do": [
      {
        "label": "Density",
        "line": "PtIr10 has a density of 21.54 g/cm3 in the Heraeus datasheet. The NIST paper gives 21.55 g/cm3 for the national prototypes.",
        "benchmark": "density",
        "scope": "material",
        "value": "21.54 g/cm3"
      },
      {
        "label": "Melting",
        "line": "The PtIr10 melting range is 1790 to 1800 °C. The PtIr20 range is 1830 to 1855 °C.",
        "benchmark": "melting_point",
        "scope": "material",
        "value": "1790 to 1800 °C"
      },
      {
        "label": "Hardness",
        "line": "PtIr10 is 105 HV annealed and 215 HV work hardened. PtIr20 is 190 HV annealed and 300 HV work hardened.",
        "benchmark": "vickers_hardness",
        "scope": "material",
        "value": "215 HV work hardened"
      },
      {
        "label": "Charge injection",
        "line": "Electrodeposited PtIr on carbon fibre injected 1.25 mC/cm2 in 0.5 ms pulses in PBS, the highest density tested in that study.",
        "benchmark": "charge_injection_capacity",
        "scope": "material",
        "value": "1.25 mC/cm2"
      }
    ],
    "compare": "The Heraeus datasheets show that moving from PtIr10 to PtIr20 raises the density, melting range, Young's modulus and hardness, and lowers the electrical conductivity. The rows below compare the two grades, not other materials.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Melting point",
        "benchmark": "melting_point",
        "scope": "material"
      },
      {
        "label": "Young's modulus",
        "benchmark": "elastic_modulus",
        "scope": "material"
      }
    ],
    "handling": [
      "State the temper with every strength value. PtIr10 yield strength is 220 MPa annealed and 630 MPa work hardened.",
      "Keep fine forms away from heat and ignition sources, since PubChem gives H228 for the element records.",
      "Clean the surface gently. The Wikipedia article describes rubbing with ether and ethanol, then steam, for the kilogram prototype."
    ],
    "good_for": [
      "Reference artefacts where a stable, dense metal matters. The kilogram prototype is 90 % platinum and 10 % iridium.",
      "Thermocouple and spark plug electrodes, as listed by Heraeus for PtIr10.",
      "Medical wire and probe needles, as listed by Heraeus for PtIr20."
    ],
    "watch_out": [
      "Annealed PtIr10 is soft at 105 HV. Work hardening raises it to 215 HV but cuts elongation to 2 %.",
      "Surface contamination moves the mass of the kilogram prototype. The Wikipedia article gives about 50 μg lost over a century against its copies.",
      "No space-electrode source, thermal conductivity, expansion or outgassing value was read for the alloy in this run."
    ],
    "verdict": "Platinum-iridium is a dense, hard and stable platinum alloy. PtIr10 is the standard composition, and PtIr20 is the harder grade. The datasheets and the NIST paper give density, mechanical and conductivity values, but the space-electrode use and the thermal properties remain unsourced.",
    "recipe": {
      "line": "Pt-10Ir is a binary alloy of platinum and iridium, 90 % platinum and 10 % iridium by mass. The NIST paper says the ingots of the kilogram prototype were swaged until their density reached a maximum. The Wikipedia article says the metre bar was made in an X-shaped section from the same alloy.",
      "parts": [
        {
          "name": "Platinum",
          "symbol": "Pt",
          "role": "The main component. It gives the alloy its high density (21.54 g/cm3 for PtIr10 in the Heraeus datasheet).",
          "share_percent": 90
        },
        {
          "name": "Iridium",
          "symbol": "Ir",
          "role": "Added to raise the hardness. The Wikipedia article says the alloy is significantly harder than pure platinum.",
          "share_percent": 10
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The platinum and iridium element records carry flammable-solid and irritation codes in some company reports. The alloy has no record of its own.",
        "points": [
          {
            "label": "Platinum element",
            "line": "Of 504 company reports, 410 said platinum does not meet GHS criteria. H228 (flammable solid, 10.7 %) is shown with the signal word Danger, and H334 (respiratory sensitisation) comes from 94 of 504 reports."
          },
          {
            "label": "Iridium element",
            "line": "Of 249 company reports, 92 said iridium does not meet GHS criteria. H228 (18.1 %), H319 (20.1 %) and H413 (41.8 %) are shown, with the signal word Danger."
          }
        ],
        "level": 1,
        "verdict": "Mixed element records"
      },
      {
        "title": "If it fails",
        "lead": "The only failure route in a read source is a coating crack, found in a preliminary test.",
        "points": [
          {
            "label": "Coating crack",
            "line": "The 2021 study reports a crack in the PtIr film near the electrode tip after in vivo stimulation. The authors think deposition, handling or SEM preparation more likely caused it."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Fine forms",
            "line": "PubChem gives H228 (flammable solid) for both element records, so keep fine forms away from heat and ignition sources."
          },
          {
            "label": "Cleaning the prototype",
            "line": "The Wikipedia article describes cleaning with ether and ethanol, then steam. It says cleaning removes between 5 and 60 μg of contamination."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 28,
    "unreachable": 1,
    "caveats": 6,
    "note": "Values were read by an AI assistant on 2026-10-26 from the Heraeus datasheets, the NIST paper, Wikipedia, PubChem, the USGS MCS 2026 PGM chapter and one 2021 paper. Unreachable: the Heraeus product page and the Matthey article (403). Caveats: the datasheets give no temperatures; the metre prototype figures are secondary; the charge injection value is for a coating on carbon fibre; the platinum shares are calculated from kilogram values; no space-electrode source; the hazard records are for the elements."
  },
  "sources": {
    "heraeus-pt10ir": {
      "title": "Hera 173, PtIr10, Heraeus Precious Metals datasheet (status 11/2021)",
      "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_173_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
      "year": 2021,
      "kind": "datasheet",
      "license": "Manufacturer datasheet (cited, not reproduced)"
    },
    "heraeus-pt20ir": {
      "title": "Hera 174, PtIr20, Heraeus Precious Metals datasheet (status 09/2021)",
      "url": "https://pim.heraeus.com/datasheets/HPM/FM/Contact%20Materials/Hera_174_Datasheet_EN_(Heraeus_Precious_Metals).pdf",
      "year": 2021,
      "kind": "datasheet",
      "license": "Manufacturer datasheet (cited, not reproduced)"
    },
    "nist-v90-4": {
      "title": "Davis, Recalibration of the U.S. National Prototype Kilogram, Journal of Research of NBS, volume 90, number 4 (1985)",
      "url": "https://nvlpubs.nist.gov/nistpubs/jres/090/4/V90-4.pdf",
      "year": 1985,
      "kind": "paper",
      "license": "public domain (NIST)"
    },
    "wikipedia-ipk": {
      "title": "Wikipedia: International Prototype of the Kilogram (composition, stability and cleaning sections)",
      "url": "https://en.wikipedia.org/wiki/International_Prototype_of_the_Kilogram",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    },
    "wikipedia-metre": {
      "title": "Wikipedia: Mètre des Archives (metre prototype, composition and shape)",
      "url": "https://en.wikipedia.org/wiki/M%C3%A8tre_des_Archives",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    },
    "pubchem-ir": {
      "title": "PubChem compound record, Iridium (CID 23924), GHS classification and CAS number",
      "id": "CID 23924, CAS 7439-88-5",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23924/JSON",
      "kind": "database",
      "license": "PubChem (NCBI), public domain; sections attributed to ECHA and others"
    },
    "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)"
    },
    "frontiers-ptir": {
      "title": "Electrodeposited Platinum Iridium Enables Microstimulation With Carbon Fiber Electrodes (Frontiers in Nanotechnology, 2021)",
      "id": "doi:10.3389/fnano.2021.782883",
      "url": "https://www.frontiersin.org/journals/nanotechnology/articles/10.3389/fnano.2021.782883/full",
      "year": 2021,
      "kind": "paper",
      "license": "open access (cited, not reproduced)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/platinum-iridium/"
}