{
  "spore": "profile",
  "id": "evanohm",
  "spore_version": "0.2",
  "family": "resistance-and-thermocouple-alloys",
  "name": "Evanohm",
  "abbreviation": "Ni-Cr-Al-Cu precision resistance alloy",
  "role": "precision resistance alloy",
  "category": "metals",
  "type": "nickel-superalloys",
  "summary": "Evanohm is a nickel-chromium-aluminium-copper precision resistance alloy. Goodfellow gives its composition as Ni 75 / Cr 20 / Al 2.5 / Cu 2.5 (UNS N06720, EN 2.4872), and the Carpenter nominal analysis for Evanohm R is 73.5 % Ni with 2.5 % Al, 2.0 % Cu, 1.0 % Mn and 1.0 % Si. Its electrical resistivity is 133 µΩ·cm at room temperature (Hamilton Precision Metals), its temperature coefficient of resistance is ±10 ppm/°C, and its thermal EMF against copper is 1.0 µV/°C (Matthey). It melts at about 1350 °C and is rated to 300 °C maximum use in air (Goodfellow). Evanohm is a Karma-type alloy: Wikipedia lists Evanohm and Karma side by side as constant-resistance trade names, but no Karma values were read for this profile.\n",
  "best_for": "Precision and strain-gauge resistors: a temperature coefficient of about ±10 ppm/°C with 133 µΩ·cm resistivity, and very low thermal EMF against copper (1.0 µV/°C)",
  "weakest_at": "Heat and load: Goodfellow gives 300 °C maximum use in air and no oxidation rate, and the annealed strip has a yield strength of only 300 MPa minimum",
  "identity": {
    "formula": "Nickel-chromium-aluminium-copper alloy, Ni 75 / Cr 20 / Al 2.5 / Cu 2.5 by mass (Goodfellow); Carpenter nominal for Evanohm R: Ni 73.50, Cr 20.00, Al 2.50, Cu 2.00, Mn 1.00, Si 1.00",
    "designations": [
      {
        "system": "UNS",
        "code": "N06720",
        "source": "goodfellow-evanohm-foil",
        "where": "Properties common to all products list, UNS Number"
      },
      {
        "system": "EN",
        "code": "2.4872",
        "source": "matthey-evanohm-r",
        "where": "Designation table, EN column"
      },
      {
        "system": "Trade name",
        "code": "Evanohm",
        "note": "Trade names table lists Evanohm under the Carpenter Tech column",
        "source": "wikipedia-resistance-wire",
        "where": "Trade names table, row MWS-800"
      }
    ],
    "source": "goodfellow-evanohm-foil",
    "where": "Properties common to all products list, Composition line (Ni 75/Cr20/Al 2.5/Cu 2.5); the Carpenter nominal analysis is in the Type Analysis table of carpenter-evanohm-r"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "extreme-heat"
    ],
    "applications": [
      "electronics-and-chips",
      "thermal-control",
      "structures"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, Evanohm R strip",
      "value": 8.1,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip datasheet)",
        "temperature": "not stated",
        "form": "strip"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-evanohm-r",
      "where": "Physical properties table, Density row",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, Evanohm foil (Goodfellow)",
      "value": 8.1,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm foil (Ni 75 / Cr 20 / Al 2.5 / Cu 2.5)",
        "temperature": "not stated",
        "form": "foil"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-evanohm-foil",
      "where": "Physical Properties table, Density (g cm-3)",
      "source_detail": {
        "title": "Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow)",
        "url": "https://www.goodfellow.com/usa/evanohm-foil-group",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, Evanohm R (approximate)",
      "value": 1350,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R",
        "pressure": "not stated"
      },
      "method": "Value printed in a manufacturer product page, marked approximate",
      "status": "ground",
      "source": "hpm-evanohm-r",
      "where": "Physical Properties of Evanohm R Alloy, Melting Point (Approx.)",
      "source_detail": {
        "title": "Evanohm R Strip and Foil (Hamilton Precision Metals)",
        "url": "https://www.hpmetals.com/products/materials/evanohm-r-strip-foil",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting range, Evanohm foil",
      "value": 1340,
      "value_high": 1390,
      "bound": "range",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm foil",
        "pressure": "not stated"
      },
      "method": "Range printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-evanohm-foil",
      "where": "Physical Properties table, Melting point row",
      "source_detail": {
        "title": "Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow)",
        "url": "https://www.goodfellow.com/usa/evanohm-foil-group",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "label": "Electrical resistivity at room temperature, Evanohm R",
      "value": 133,
      "bound": "exact",
      "unit": "µΩ·cm",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R",
        "temperature": "room temperature (R.T.)",
        "unit_in_source": "Microhm·cm"
      },
      "method": "Value printed in a manufacturer product page",
      "status": "ground",
      "source": "hpm-evanohm-r",
      "where": "Physical Properties of Evanohm R Alloy, Electrical Resistivity @ R.T.",
      "source_detail": {
        "title": "Evanohm R Strip and Foil (Hamilton Precision Metals)",
        "url": "https://www.hpmetals.com/products/materials/evanohm-r-strip-foil",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "label": "Electrical resistivity, Evanohm foil",
      "value": 134,
      "bound": "exact",
      "unit": "µΩ·cm",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm foil",
        "temperature": "not stated",
        "unit_in_source": "µOhmcm"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "note": "Goodfellow gives 134 and Hamilton gives 133 for the same nominal alloy; both are kept.",
      "source": "goodfellow-evanohm-foil",
      "where": "Electrical Properties table, Electrical resistivity row",
      "source_detail": {
        "title": "Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow)",
        "url": "https://www.goodfellow.com/usa/evanohm-foil-group",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "temperature_coefficient_of_resistance",
      "label": "Temperature coefficient of resistance, heat-treated Evanohm R",
      "value": 10,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R",
        "temperature": "-55 to 105 °C",
        "temper": "heat treated (stabilising heat treatment of about 475 °C)",
        "sign": "printed as ± 10"
      },
      "method": "Value printed in a manufacturer product page",
      "status": "ground",
      "note": "Non-canonical property name; the canonical property file has no temperature coefficient of resistance entry.",
      "source": "hpm-evanohm-r",
      "where": "Physical Properties of Evanohm R Alloy, Temperature Coefficient of Resistivity (TCR), heat treated",
      "source_detail": {
        "title": "Evanohm R Strip and Foil (Hamilton Precision Metals)",
        "url": "https://www.hpmetals.com/products/materials/evanohm-r-strip-foil",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "temperature_coefficient_of_resistance",
      "label": "Temperature coefficient of resistance, -65 to +125 °C",
      "value": 10,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temperature": "-65 to +125 °C",
        "sign": "printed as ± 10"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "note": "Non-canonical property name. Matthey prints the same ±10 ppm/°C in its main-features text.",
      "source": "matthey-evanohm-r",
      "where": "Physical properties table, Temperature Coefficient of Resistance row, TCR -65 to +125 ºC",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "temperature_coefficient_of_resistance",
      "label": "Temperature coefficient of resistance, -55 to +25 °C",
      "value": 5,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temperature": "-55 to +25 °C",
        "sign": "printed as + 5.0"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "note": "Non-canonical property name. The TCR is not constant over the range: Matthey prints +5.0 below 25 °C and -5.0 from 25 to 125 °C.",
      "source": "matthey-evanohm-r",
      "where": "Physical properties table, Temperature Coefficient of Resistance row, TCR -55 to +25 ºC",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "temperature_coefficient_of_resistance",
      "label": "Temperature coefficient of resistance, +25 to +125 °C",
      "value": -5,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temperature": "+25 to +125 °C",
        "sign": "printed as - 5.0"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "note": "Non-canonical property name.",
      "source": "matthey-evanohm-r",
      "where": "Physical properties table, Temperature Coefficient of Resistance row, TCR +25 to +125 ºC",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity at 20 °C, Evanohm R",
      "value": 14.6,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temperature": "20 °C",
        "unit_in_source": "W/m °K"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-evanohm-r",
      "where": "Physical properties table, Thermal conductivity at 20 ºC",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat capacity at 20 °C, Evanohm R",
      "value": 435,
      "bound": "exact",
      "unit": "J/(kg·K)",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temperature": "20 °C",
        "unit_in_source": "J/(kg. K)"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-evanohm-r",
      "where": "Physical properties table, Specific heat at 20 ºC",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion at 100 °C, Evanohm R",
      "value": 13,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temperature": "100 °C",
        "unit_in_source": "10⁻⁶/°C"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "note": "Hamilton also prints 13 x 10-6 /°C for 20 to 100 °C, so the two sources agree.",
      "source": "matthey-evanohm-r",
      "where": "Physical properties table, Linear dilatation coefficient at 100 ºC",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion, 20 to 100 °C, Evanohm foil",
      "value": 11.7,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm foil",
        "temperature": "20 to 100 °C",
        "unit_in_source": "x10⁻⁶ K⁻¹"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "note": "Goodfellow prints 11.7, while Matthey and Hamilton print 13 for a similar range. Both are kept; the difference is not explained by the sources.",
      "source": "goodfellow-evanohm-foil",
      "where": "Physical Properties table, Coefficient of thermal expansion row, 20-100°C",
      "source_detail": {
        "title": "Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow)",
        "url": "https://www.goodfellow.com/usa/evanohm-foil-group",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Modulus of elasticity, Evanohm foil",
      "value": 221,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm foil",
        "temper": "not stated",
        "form": "foil"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-evanohm-foil",
      "where": "Mechanical Properties table, Modulus of elasticity row",
      "source_detail": {
        "title": "Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow)",
        "url": "https://www.goodfellow.com/usa/evanohm-foil-group",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength Rm, annealed strip",
      "value": 650,
      "value_high": 900,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temper": "annealed",
        "form": "strip",
        "unit_in_source": "N/mm2"
      },
      "method": "Range printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-evanohm-r",
      "where": "Mechanical properties of strips, annealed row, Rm",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength Rm, hard strip",
      "value": 1200,
      "bound": "lower",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temper": "hard",
        "form": "strip",
        "unit_in_source": "N/mm2"
      },
      "method": "Minimum printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-evanohm-r",
      "where": "Mechanical properties of strips, hard row, Rm min",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, annealed (Hamilton)",
      "value": 120000,
      "bound": "exact",
      "unit": "psi",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R",
        "temper": "annealed",
        "form": "foil and strip"
      },
      "method": "Value printed in a manufacturer product page",
      "status": "ground",
      "source": "hpm-evanohm-r",
      "where": "Typical Mechanical Properties of Evanohm R Alloy, Ultimate Tensile Strength, ANNEALED column",
      "source_detail": {
        "title": "Evanohm R Strip and Foil (Hamilton Precision Metals)",
        "url": "https://www.hpmetals.com/products/materials/evanohm-r-strip-foil",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, heat treated (Hamilton)",
      "value": 240000,
      "bound": "exact",
      "unit": "psi",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R",
        "temper": "heat treated",
        "form": "foil and strip"
      },
      "method": "Value printed in a manufacturer product page",
      "status": "ground",
      "source": "hpm-evanohm-r",
      "where": "Typical Mechanical Properties of Evanohm R Alloy, Ultimate Tensile Strength, HEAT TREATED column",
      "source_detail": {
        "title": "Evanohm R Strip and Foil (Hamilton Precision Metals)",
        "url": "https://www.hpmetals.com/products/materials/evanohm-r-strip-foil",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, Evanohm foil",
      "value": 1210,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm foil",
        "temper": "not stated",
        "form": "foil"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-evanohm-foil",
      "where": "Mechanical Properties table, Tensile strength row",
      "source_detail": {
        "title": "Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow)",
        "url": "https://www.goodfellow.com/usa/evanohm-foil-group",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength Rp0.2, annealed strip, minimum",
      "value": 300,
      "bound": "lower",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temper": "annealed",
        "form": "strip",
        "unit_in_source": "N/mm2"
      },
      "method": "Minimum printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-evanohm-r",
      "where": "Mechanical properties of strips, annealed row, Rp0.2 min",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength Rp0.2, hard strip, minimum",
      "value": 900,
      "bound": "lower",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temper": "hard",
        "form": "strip",
        "unit_in_source": "N/mm2"
      },
      "method": "Minimum printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-evanohm-r",
      "where": "Mechanical properties of strips, hard row, Rp0.2 min",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "yield_strength",
      "label": "Yield strength Rp0.2 (0.2 % offset), heat treated (Hamilton)",
      "value": 235000,
      "bound": "exact",
      "unit": "psi",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R",
        "temper": "heat treated",
        "form": "foil and strip"
      },
      "method": "Value printed in a manufacturer product page",
      "status": "ground",
      "source": "hpm-evanohm-r",
      "where": "Typical Mechanical Properties of Evanohm R Alloy, Yield Strength (0.2% Offset), HEAT TREATED column",
      "source_detail": {
        "title": "Evanohm R Strip and Foil (Hamilton Precision Metals)",
        "url": "https://www.hpmetals.com/products/materials/evanohm-r-strip-foil",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation A50, annealed strip, minimum",
      "value": 30,
      "bound": "lower",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temper": "annealed",
        "form": "strip"
      },
      "method": "Minimum printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-evanohm-r",
      "where": "Mechanical properties of strips, annealed row, A50mm min",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, Evanohm foil",
      "value": 33,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm foil",
        "temper": "not stated",
        "form": "foil"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-evanohm-foil",
      "where": "Mechanical Properties table, Elongation at break row",
      "source_detail": {
        "title": "Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow)",
        "url": "https://www.goodfellow.com/usa/evanohm-foil-group",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "hardness_vickers",
      "label": "Hardness HV, annealed strip",
      "value": 160,
      "value_high": 280,
      "bound": "range",
      "unit": "HV",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temper": "annealed",
        "form": "strip"
      },
      "method": "Range printed in a manufacturer datasheet",
      "status": "ground",
      "note": "Non-canonical property name; hardness_vickers is not in the canonical property file.",
      "source": "matthey-evanohm-r",
      "where": "Mechanical properties of strips, annealed row, Hardness HV",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_emf_vs_copper",
      "label": "Thermal EMF against pure copper, 0 to 100 °C",
      "value": 1,
      "bound": "exact",
      "unit": "µV/°C",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R (Matthey strip)",
        "temperature": "0 to 100 °C"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "note": "Non-canonical property name. Hamilton prints <1.0 Millivolts/°C for the same figure, which is a different unit and is not used.",
      "source": "matthey-evanohm-r",
      "where": "Physical properties table, Thermal EMF versus pure copper from 0 to 100 ºC",
      "source_detail": {
        "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
        "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "Manufacturer datasheet (cited, not reproduced)"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum use temperature in air, Evanohm foil",
      "value": 300,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm foil",
        "environment": "air"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-evanohm-foil",
      "where": "Thermal Properties table, Maximum use temperature in air row",
      "source_detail": {
        "title": "Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow)",
        "url": "https://www.goodfellow.com/usa/evanohm-foil-group",
        "kind": "web",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "temperature_coefficient_of_resistance",
      "label": "Standard temperature coefficient, Evanohm R (Carpenter)",
      "value": 10,
      "bound": "exact",
      "unit": "ppm/°C",
      "scope": "material",
      "conditions": {
        "grade": "Evanohm R",
        "temperature": "not stated",
        "sign": "printed as ±10 parts per million per °C"
      },
      "method": "Value printed in a manufacturer product page",
      "status": "ground",
      "note": "Non-canonical property name. Carpenter describes the standard grade; the heat-treated value is the Hamilton row above.",
      "source": "carpenter-evanohm-r",
      "where": "Product description paragraph, standard temperature coefficient",
      "source_detail": {
        "title": "Evanohm R, specialty alloys (Carpenter Technology)",
        "url": "https://www.carpentertechnology.com/alloy-finder/Evanohm-R",
        "kind": "web",
        "license": "Manufacturer product page (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Humid air",
      "headline": "Excellent corrosion resistance in humid environments.",
      "effect": "Matthey describes the alloy as having excellent corrosion resistance in humid environments. Carpenter describes high corrosion resistance. Neither gives a corrosion rate, test duration or humidity level.",
      "rating": "low",
      "conditions": {
        "environment": "humid air",
        "basis": "manufacturer datasheet wording; no test data printed"
      },
      "source": "matthey-evanohm-r",
      "where": "Main technical properties and features, second paragraph"
    },
    {
      "environment": "Mineral acids (nitric, phosphoric, sulfuric)",
      "headline": "Good resistance to nitric, phosphoric and sulfuric acids.",
      "effect": "Matthey lists good corrosion resistance to these three mineral acids. No concentration, temperature or attack rate is printed.",
      "rating": "low",
      "conditions": {
        "basis": "manufacturer datasheet wording; no concentration or temperature stated"
      },
      "source": "matthey-evanohm-r",
      "where": "Main technical properties and features, second paragraph"
    },
    {
      "environment": "Seawater",
      "headline": "Moderate resistance to seawater.",
      "effect": "Matthey rates resistance to seawater as moderate, which is lower than its humid-air and mineral-acid rating. No attack rate, exposure time or temperature is printed.",
      "rating": "moderate",
      "conditions": {
        "basis": "manufacturer datasheet wording; no test data printed"
      },
      "source": "matthey-evanohm-r",
      "where": "Main technical properties and features, second paragraph"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem gives nickel (CID 935) the GHS statements H317 (may cause an allergic skin reaction), H351 (suspected of causing cancer) and H372 (causes damage to organs through prolonged or repeated exposure), with signal word Danger. The classification is for nickel, the main element in the alloy, not for the finished alloy.",
        "ghs": [],
        "source": "pubchem-nickel",
        "where": "Safety and Hazards, GHS Classification, Hazard Statements"
      },
      {
        "text": "PubChem notes that this chemical does not meet GHS hazard criteria in 5 of 4778 company reports (0.1 %), so most nickel reports carry hazard codes.",
        "ghs": [],
        "source": "pubchem-nickel",
        "where": "Safety and Hazards, ECHA C&L Notifications Summary"
      },
      {
        "text": "The Airgas safety data sheet for nickel wire and rod classifies the product as Not Classified under GHS, with no hazard symbol or signal word. The sheet covers nickel wire and rod, not Evanohm.",
        "ghs": [],
        "source": "airgas-nickel-sds",
        "where": "Section 2, GHS Hazard Classification line"
      },
      {
        "text": "The same Airgas sheet notes that IARC classifies nickel as a possible carcinogen to humans (Group 2B), and that the National Toxicology Program lists nickel as reasonably anticipated to be a human carcinogen.",
        "ghs": [],
        "source": "airgas-nickel-sds",
        "where": "Health hazard section, Carcinogenicity text"
      }
    ],
    "failure_risks": [
      {
        "mode": "Resistance drift above the working temperature",
        "trigger": "Use above about 204 °C in service, which is the temperature up to which Matthey says resistivity hardly varies",
        "consequence": "Matthey gives no drift rate above 204 °C, so the stability of a resistor run hotter than this cannot be read from the sources.",
        "severity": "moderate",
        "source": "matthey-evanohm-r",
        "where": "Main technical properties and features, first paragraph (resistivity hardly varies up to 204 ºC)"
      },
      {
        "mode": "Oxidation above the maximum use temperature",
        "trigger": "Operation above 300 °C in air (Goodfellow maximum use temperature)",
        "consequence": "Goodfellow gives 300 °C as the maximum use temperature in air but no oxidation rate, scale thickness or time to failure.",
        "severity": "moderate",
        "source": "goodfellow-evanohm-foil",
        "where": "Thermal Properties table, Maximum use temperature in air"
      }
    ],
    "side_effects": [
      {
        "text": "Nickel makes up most of the alloy, so dust or fume from grinding or welding contains nickel compounds. The Airgas sheet lists nickel as an IARC Group 2B possible carcinogen.",
        "affects": "Handling of dust and fume from grinding or welding",
        "source": "airgas-nickel-sds",
        "where": "Health hazard section, Carcinogenicity text"
      }
    ],
    "handling": [
      {
        "text": "Anneal between 400 and 600 °C (Matthey). Hamilton gives a stabilising heat treatment of about 475 °C to set the TCR of finished parts.",
        "source": "matthey-evanohm-r",
        "where": "Heat treatment section"
      },
      {
        "text": "Hamilton says the heat treatment virtually eliminates resistivity drift, and that a heat-treat curve is developed for each melt to regulate the TCR.",
        "source": "hpm-evanohm-r",
        "where": "Evanohm R Strip and Foil description paragraph"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "structures",
      "device": "Strain gauges",
      "example": "Matthey says Evanohm is the material of choice for strain gauges and electrical resistors, because of its combination of low TCR and corrosion resistance. Hamilton lists strain gauges as a main use.",
      "source": "matthey-evanohm-r",
      "where": "Typical uses section"
    },
    {
      "application": "electronics-and-chips",
      "device": "Precision resistors",
      "example": "Matthey lists electrical resistors as a typical use. Carpenter lists the alloy for precision use, with the standard ±10 ppm/°C temperature coefficient.",
      "source": "matthey-evanohm-r",
      "where": "Typical uses section"
    },
    {
      "application": "electronics-and-chips",
      "device": "Precision current-sense resistors in measurement instruments",
      "example": "Goodfellow lists precision current-sense resistors in measurement instrumentation, and stable resistance elements in aerospace-grade control systems.",
      "source": "goodfellow-evanohm-foil",
      "where": "Product description paragraph, specific uses sentence"
    },
    {
      "application": "thermal-control",
      "device": "Foil heaters",
      "example": "Hamilton lists foil heaters as a use for Evanohm R strip and foil. Hamilton gives the alloy's supplied form as foil and strip down to 0.000100 in thick.",
      "source": "hpm-evanohm-r",
      "where": "Evanohm R Strip and Foil description paragraph; Sizes section"
    }
  ],
  "supply": [
    {
      "subject": "Nickel",
      "producers": [
        {
          "country": "Indonesia",
          "share_percent": 66.7,
          "year": 2025
        },
        {
          "country": "Philippines",
          "share_percent": 6.9,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 5.1,
          "year": 2025
        },
        {
          "country": "Canada",
          "share_percent": 3.6,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: in 2025 nickel recovered from scrap accounted for approximately 60% of apparent consumption.",
      "substitutes": [
        "USGS: low-nickel, duplex or ultrahigh-chromium stainless steels replace austenitic grades in some uses; titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments."
      ],
      "source": "usgs-mcs2026-nickel",
      "where": "World Mine Production and Reserves table, 2025e column (world total 3,900,000 t; shares calculated by Space Mushroom against that printed total); Recycling; Substitutes"
    },
    {
      "subject": "Chromium",
      "producers": [
        {
          "country": "South Africa",
          "share_percent": 45.1,
          "year": 2025
        },
        {
          "country": "Turkey",
          "share_percent": 17.6,
          "year": 2025
        },
        {
          "country": "Kazakhstan",
          "share_percent": 13.7,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: recycled chromium in reported stainless-steel scrap receipts accounted for 21% of apparent consumption in 2025.",
      "substitutes": [
        "USGS: chromium has no substitute in stainless steel, the leading end use, or in superalloys."
      ],
      "source": "usgs-mcs2026-chromium",
      "where": "World Mine Production and Reserves table, 2025e column (world total 51,000 thousand t; shares calculated by Space Mushroom; Kazakhstan value is estimated by USGS); Recycling; Substitutes"
    },
    {
      "subject": "Aluminium (primary smelter output)",
      "producers": [
        {
          "country": "China",
          "share_percent": 60.8,
          "year": 2025
        },
        {
          "country": "India",
          "share_percent": 5.7,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 5.3,
          "year": 2025
        },
        {
          "country": "Canada",
          "share_percent": 4.5,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: in 2025 about 3.6 million tons of aluminum were recovered from purchased scrap in the United States (U.S. figure only).",
      "substitutes": [
        "USGS: composites can substitute for aluminum in aircraft fuselages and wings; glass, paper, plastics and steel can substitute in packaging."
      ],
      "source": "usgs-mcs2026-aluminum",
      "where": "World Smelter Production table, 2025e column (world total 74,000 thousand t; shares calculated by Space Mushroom); Recycling; Substitutes. Aluminum is a 2.5 % constituent of this alloy."
    },
    {
      "subject": "Copper",
      "producers": [
        {
          "country": "Chile",
          "share_percent": 23,
          "year": 2025
        },
        {
          "country": "Congo (Kinshasa)",
          "share_percent": 13.9,
          "year": 2025
        },
        {
          "country": "Peru",
          "share_percent": 11.7,
          "year": 2025
        },
        {
          "country": "China",
          "share_percent": 7.8,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 List of Critical Minerals (copper added in the final 2025 list)",
          "listed": true
        }
      ],
      "recycling": "USGS: old scrap converted to refined metal, alloys and other forms provided an estimated 160,000 tons of copper in 2025.",
      "substitutes": [
        "USGS: aluminum substitutes for copper in several uses, and optical fiber substitutes in telecommunications."
      ],
      "source": "usgs-mcs2026-copper",
      "where": "World Mine and Refinery Production table, Mine production 2025e column (world total 23,000 thousand t; shares calculated by Space Mushroom); Final 2025 List of Critical Minerals paragraph; Substitutes. Copper is a 2.0 to 2.5 % constituent of this alloy."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Goodfellow: Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy product page",
      "type": "datasheet",
      "url": "https://www.goodfellow.com/usa/evanohm-foil-group",
      "year": 2025
    },
    {
      "title": "Lamineries Matthey: Evanohm datasheet (EvanohmR_v24E)",
      "type": "datasheet",
      "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
      "year": 2024
    },
    {
      "title": "Hamilton Precision Metals: Evanohm R Strip and Foil product page",
      "type": "datasheet",
      "url": "https://www.hpmetals.com/products/materials/evanohm-r-strip-foil"
    },
    {
      "title": "Carpenter Technology: Evanohm R specialty alloy page",
      "type": "datasheet",
      "url": "https://www.carpentertechnology.com/alloy-finder/Evanohm-R"
    },
    {
      "title": "Wikipedia: Resistance wire (trade names table)",
      "type": "database",
      "url": "https://en.wikipedia.org/wiki/Resistance_wire"
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Nickel",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Chromium",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Aluminum",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Copper",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf",
      "year": 2026
    },
    {
      "title": "PubChem: Nickel (CID 935), GHS classification summary",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/935",
      "year": 2026
    },
    {
      "title": "Airgas Nickel Wire and Rod safety data sheet, SDS 011-Ni Wire and Rod",
      "type": "sds",
      "url": "https://www.airgas.com/msds/005727.pdf"
    }
  ],
  "gaps": [
    "Evanohm S grade not read: the CarTech Evanohm S and R datasheet pages returned no readable content in this run, and the ASM Alloy Digest entries are paywalled.",
    "Karma values not read. The only Karma source was an ASM Alloy Digest entry that is paywalled. Karma appears in the Wikipedia trade-names table under Driver-Harris, so it is a related alloy and not an alias; no Karma property is recorded here.",
    "Matthey's composition table omits copper, but its designation (NiCr20Al2.5Cu2Mn1Si1) includes Cu 2. Copper is taken from Goodfellow and Carpenter only.",
    "Matthey's designation table lists UNS N10276 against this grade. Hamilton prints N10276 as its Hastelloy C-276 strip, so the code is not used here.",
    "Matthey's resistivity row prints 133 with the unit cut off in the PDF text, so the value is taken from Hamilton (133 µΩ·cm) and Goodfellow (134 µΩ·cm) instead.",
    "Temperature coefficient of resistance and thermal EMF against copper are not canonical property names (temperature_coefficient_of_resistance, thermal_emf_vs_copper). Hardness_vickers is also non-canonical, as in the nichrome profile.",
    "Coefficient of thermal expansion disagrees between sources: Matthey and Hamilton print 13 x 10-6/°C, Goodfellow prints 11.7 x 10-6/K. All three are kept with their sources.",
    "Carpenter prints a stability figure of 1 to 15 microhms per year. The unit and basis are not clear from the page, so it is not recorded.",
    "No corrosion rate, oxidation rate, outgassing, atomic-oxygen or radiation data were found for Evanohm. No NASA or ESA flight heritage was found in a search, so the profile has no space application source.",
    "Atomic weights of nickel, chromium, aluminium and copper were not read from a fetched page, so the recipe parts carry shares only.",
    "Critical-mineral list status for nickel, chromium and aluminium: the 2026 USGS nickel, chromium and aluminum summaries read in this run do not name a critical-minerals list, so no list entry is recorded for them. EU critical raw materials list not read.",
    "No CAS number was read for this alloy.",
    "Hazard data are for nickel (PubChem) and for a nickel wire and rod (Airgas). No SDS for Evanohm itself was read."
  ],
  "story": {
    "why": "Evanohm is a precision resistance alloy. It is nickel-chromium with aluminium and copper, and it was made to give a resistance that changes very little with temperature. Matthey and Hamilton give a temperature coefficient of about ±10 ppm/°C, with a resistivity of 133 µΩ·cm at room temperature (Hamilton) and a thermal EMF of 1.0 µV/°C against copper (Matthey). Those three figures make it a precision resistor alloy, not a heating alloy. Its weak points are the 300 °C maximum use temperature in air and the limited sources for stability at temperature.",
    "uses": [
      {
        "where": "Strain gauges and precision resistors",
        "line": "Matthey calls Evanohm the material of choice for strain gauges and electrical resistors. Goodfellow adds precision current-sense resistors in measurement instruments and stable resistance elements in aerospace-grade control systems."
      },
      {
        "where": "Foil heaters",
        "line": "Hamilton lists foil heaters and airbag igniters among the uses of its Evanohm R strip and foil."
      }
    ],
    "can_do": [
      {
        "label": "Stay at a fixed resistance",
        "line": "Hamilton gives ±10 ppm/°C from -55 to 105 °C in heat-treated material. Matthey gives ±10 ppm/°C from -65 to 125 °C.",
        "benchmark": "temperature_coefficient_of_resistance",
        "scope": "material",
        "value": "±10 ppm/°C"
      },
      {
        "label": "Carry current as a resistor",
        "line": "Hamilton prints 133 µΩ·cm at room temperature. Goodfellow prints 134 µΩ·cm for the foil grade.",
        "benchmark": "electrical_resistivity",
        "scope": "material",
        "value": "133 µΩ·cm"
      },
      {
        "label": "Stay solid when hot",
        "line": "Hamilton prints 1350 °C as the approximate melting point. Goodfellow prints a range of 1340 to 1390 °C.",
        "benchmark": "melting_point",
        "scope": "material",
        "value": "1350 °C melting point"
      },
      {
        "label": "Low thermal EMF",
        "line": "Matthey prints a thermal EMF of 1.0 µV/°C against pure copper from 0 to 100 °C, which matters for low-level measurements where a copper lead meets the resistor.",
        "benchmark": "thermal_emf_vs_copper",
        "scope": "material",
        "value": "1.0 µV/°C against copper"
      }
    ],
    "compare": "Evanohm sits among the constant-resistance alloys. Wikipedia lists it with manganin and Cupron, and the trade-name table places it beside Karma. The profile gives Evanohm's own figures, not a ranking against those alloys, because Karma and the other manganin-type alloys were not read in this run.",
    "compare_rows": [
      {
        "label": "Electrical resistivity",
        "benchmark": "electrical_resistivity",
        "scope": "material"
      },
      {
        "label": "Temperature coefficient",
        "benchmark": "temperature_coefficient_of_resistance",
        "scope": "material"
      },
      {
        "label": "Maximum use temperature",
        "benchmark": "max_service_temp",
        "scope": "material"
      }
    ],
    "handling": [
      "Keep continuous service at or below 300 °C in air (Goodfellow).",
      "Anneal at 400 to 600 °C, and use the stabilising heat treatment of about 475 °C to set the TCR (Matthey and Hamilton).",
      "Treat dust and fume from grinding or welding as containing nickel and chromium compounds (Airgas)."
    ],
    "good_for": [
      "Precision resistors: about ±10 ppm/°C temperature coefficient with 133 µΩ·cm resistivity (Hamilton, Matthey).",
      "Strain gauges: named as the material of choice by Matthey, with good corrosion resistance.",
      "Low thermal EMF: 1.0 µV/°C against copper (Matthey)."
    ],
    "watch_out": [
      "Maximum use temperature of 300 °C in air (Goodfellow), with no oxidation rate printed.",
      "Strength depends on temper: annealed strip has 650 to 900 MPa tensile strength, and hard strip has 1200 MPa minimum.",
      "The temperature coefficient is not constant: Matthey prints +5.0 ppm/°C from -55 to +25 °C and -5.0 ppm/°C from +25 to +125 °C.",
      "No corrosion rate, outgassing or radiation data were found."
    ],
    "verdict": "Evanohm is a precision resistance alloy with a very low temperature coefficient, about ±10 ppm/°C, and a low thermal EMF against copper. Its resistivity of 133 µΩ·cm and its strip and foil forms suit precision resistors and strain gauges. Its limits are a 300 °C maximum use temperature in air and the lack of corrosion-rate and space-environment data in the sources read here.",
    "recipe": {
      "line": "Evanohm is a nickel-chromium alloy with aluminium and copper additions, plus small amounts of manganese and silicon. Carpenter's nominal analysis for Evanohm R is 73.50 % Ni, 20.00 % Cr, 2.50 % Al, 2.00 % Cu, 1.00 % Mn and 1.00 % Si. Matthey's composition table gives ranges for chromium, manganese, silicon and aluminium and maximum limits for carbon, sulfur and phosphorus, but it does not list copper. Goodfellow's simpler Ni 75 / Cr 20 / Al 2.5 / Cu 2.5 analysis is for foil. The alloy is melted and conditioned by the producer and then rolled to strip or foil, with an annealing step at 400 to 600 °C (Matthey).",
      "parts": [
        {
          "name": "Nickel",
          "symbol": "Ni",
          "role": "The matrix of the alloy. Carpenter prints 73.50 % nominal; Goodfellow gives 75 % for its foil grade.",
          "share_percent": 73.5
        },
        {
          "name": "Chromium",
          "symbol": "Cr",
          "role": "Forms the protective chromium oxide film and gives the alloy its oxidation and corrosion resistance. Matthey gives a range for chromium in its composition table.",
          "share_percent": 20
        },
        {
          "name": "Aluminium",
          "symbol": "Al",
          "role": "Helps set the temperature coefficient of resistance and the resistivity response to heat treatment. Matthey gives a wider range for aluminium in its composition table.",
          "share_percent": 2.5
        },
        {
          "name": "Copper",
          "symbol": "Cu",
          "role": "Included in the nominal analysis; Matthey's designation lists Cu 2 but its composition table does not give copper.",
          "share_percent": 2
        },
        {
          "name": "Manganese",
          "symbol": "Mn",
          "role": "Nominal addition (Carpenter), with Matthey giving a range in its composition table.",
          "share_percent": 1
        },
        {
          "name": "Silicon",
          "symbol": "Si",
          "role": "Nominal addition (Carpenter), with Matthey giving a range in its composition table.",
          "share_percent": 1
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The alloy is mostly nickel and chromium. The sources do not classify the finished alloy, so the raw materials are the better guide.",
        "points": [
          {
            "label": "Nickel classification",
            "line": "PubChem gives nickel H317, H351 and H372 with the signal word Danger, and most company reports carry hazard codes."
          },
          {
            "label": "Supplier classification",
            "line": "The Airgas safety data sheet for nickel wire and rod is Not Classified under GHS. It is not a sheet for Evanohm itself."
          },
          {
            "label": "Carcinogenicity listing",
            "line": "The same Airgas sheet notes IARC Group 2B for nickel, and the National Toxicology Program lists nickel as reasonably anticipated to be a human carcinogen."
          }
        ],
        "level": 1,
        "verdict": "Mixed classification"
      },
      {
        "title": "If it fails",
        "lead": "The sources give temperature limits and a drift threshold, but no failure rates.",
        "points": [
          {
            "label": "Overheating",
            "line": "Goodfellow gives 300 °C as the maximum use temperature in air."
          },
          {
            "label": "Drift",
            "line": "Matthey says resistivity hardly varies up to about 204 °C. The sources give no drift rate above that."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Heat treatment",
            "line": "Anneal at 400 to 600 °C (Matthey). Hamilton uses a stabilising heat treatment of about 475 °C to set the TCR."
          },
          {
            "label": "Dust and fume",
            "line": "Dust and fume from grinding or welding contain nickel and chromium compounds."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 29,
    "unreachable": 3,
    "caveats": 4,
    "note": "Values read by an AI assistant on 2026-10-26 from the pages named in each entry. Unreachable in this run: CarTech Evanohm S and R datasheet pages (no readable content), and the ASM Alloy Digest entries for Evanohm and Karma (paywalled). Caveats: strength values are for strip and foil of different tempers, not one temper; CTE differs between Goodfellow (11.7) and Matthey and Hamilton (13); the Hamilton thermal EMF is printed in mV and is not used; the supply shares are calculated from printed world totals."
  },
  "sources": {
    "matthey-evanohm-r": {
      "title": "Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)",
      "url": "https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf",
      "year": 2024,
      "kind": "datasheet",
      "license": "Manufacturer datasheet (cited, not reproduced)"
    },
    "goodfellow-evanohm-foil": {
      "title": "Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow)",
      "url": "https://www.goodfellow.com/usa/evanohm-foil-group",
      "kind": "web",
      "license": "Supplier product page (cited, not reproduced)"
    },
    "hpm-evanohm-r": {
      "title": "Evanohm R Strip and Foil (Hamilton Precision Metals)",
      "url": "https://www.hpmetals.com/products/materials/evanohm-r-strip-foil",
      "kind": "web",
      "license": "Supplier product page (cited, not reproduced)"
    },
    "carpenter-evanohm-r": {
      "title": "Evanohm R, specialty alloys (Carpenter Technology)",
      "url": "https://www.carpentertechnology.com/alloy-finder/Evanohm-R",
      "kind": "web",
      "license": "Manufacturer product page (cited, not reproduced)"
    },
    "wikipedia-resistance-wire": {
      "title": "Resistance wire (Wikipedia)",
      "url": "https://en.wikipedia.org/wiki/Resistance_wire",
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    },
    "usgs-mcs2026-nickel": {
      "title": "Mineral Commodity Summaries 2026, Nickel",
      "id": "USGS MCS 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-mcs2026-chromium": {
      "title": "Mineral Commodity Summaries 2026, Chromium",
      "id": "USGS MCS 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-mcs2026-aluminum": {
      "title": "Mineral Commodity Summaries 2026, Aluminum",
      "id": "USGS MCS 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-mcs2026-copper": {
      "title": "Mineral Commodity Summaries 2026, Copper",
      "id": "USGS MCS 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "pubchem-nickel": {
      "title": "PubChem compound record, Nickel (CID 935)",
      "id": "CID 935",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/935",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NCBI)"
    },
    "airgas-nickel-sds": {
      "title": "Safety Data Sheet, Nickel Wire and Rod, SDS 011-Ni Wire and Rod (Airgas)",
      "url": "https://www.airgas.com/msds/005727.pdf",
      "kind": "datasheet",
      "license": "Supplier safety data sheet (cited, not reproduced)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/evanohm/"
}