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.
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'
  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
  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
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - electronics-and-chips
    - thermal-control
    - structures
properties:
  - benchmark: density
    label: Density, Evanohm R strip
    value: 8.1
    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
  - benchmark: density
    label: Density, Evanohm foil (Goodfellow)
    value: 8.1
    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)
  - benchmark: melting_point
    label: Melting point, Evanohm R (approximate)
    value: 1350
    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.)
  - 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
  - benchmark: electrical_resistivity
    label: Electrical resistivity at room temperature, Evanohm R
    value: 133
    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.
  - benchmark: electrical_resistivity
    label: Electrical resistivity, Evanohm foil
    value: 134
    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
  - benchmark: temperature_coefficient_of_resistance
    label: Temperature coefficient of resistance, heat-treated Evanohm R
    value: 10
    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
  - benchmark: temperature_coefficient_of_resistance
    label: Temperature coefficient of resistance, -65 to +125 °C
    value: 10
    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
  - benchmark: temperature_coefficient_of_resistance
    label: Temperature coefficient of resistance, -55 to +25 °C
    value: 5
    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
  - benchmark: temperature_coefficient_of_resistance
    label: Temperature coefficient of resistance, +25 to +125 °C
    value: -5
    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
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 20 °C, Evanohm R
    value: 14.6
    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
  - benchmark: specific_heat
    label: Specific heat capacity at 20 °C, Evanohm R
    value: 435
    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
  - benchmark: cte
    label: Coefficient of thermal expansion at 100 °C, Evanohm R
    value: 13
    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
  - benchmark: cte
    label: Coefficient of thermal expansion, 20 to 100 °C, Evanohm foil
    value: 11.7
    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
  - benchmark: elastic_modulus
    label: Modulus of elasticity, Evanohm foil
    value: 221
    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
  - 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
  - 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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, annealed (Hamilton)
    value: 120000
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, heat treated (Hamilton)
    value: 240000
    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
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, Evanohm foil
    value: 1210
    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
  - 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
  - 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
  - benchmark: yield_strength
    label: Yield strength Rp0.2 (0.2 % offset), heat treated (Hamilton)
    value: 235000
    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
  - 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
  - benchmark: elongation
    label: Elongation at break, Evanohm foil
    value: 33
    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
  - 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
  - benchmark: thermal_emf_vs_copper
    label: Thermal EMF against pure copper, 0 to 100 °C
    value: 1
    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
  - benchmark: max_service_temp
    label: Maximum use temperature in air, Evanohm foil
    value: 300
    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
  - benchmark: temperature_coefficient_of_resistance
    label: Standard temperature coefficient, Evanohm R (Carpenter)
    value: 10
    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
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
    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
    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
    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
    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.'
    critical_lists:
      - list: USGS 2025 List of Critical Minerals (copper added in the final 2025 list)
        listed: true
    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.
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.
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
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.'
story:
  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
        share_percent: 73.5
        role: The matrix of the alloy. Carpenter prints 73.50 % nominal; Goodfellow gives 75 % for its foil grade.
      - name: Chromium
        symbol: Cr
        share_percent: 20
        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.
      - name: Aluminium
        symbol: Al
        share_percent: 2.5
        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.
      - name: Copper
        symbol: Cu
        share_percent: 2
        role: Included in the nominal analysis; Matthey's designation lists Cu 2 but its composition table does not give copper.
      - name: Manganese
        symbol: Mn
        share_percent: 1
        role: Nominal addition (Carpenter), with Matthey giving a range in its composition table.
      - name: Silicon
        symbol: Si
        share_percent: 1
        role: Nominal addition (Carpenter), with Matthey giving a range in its composition table.
  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.
      level: 1
      verdict: Mixed classification
      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.
    - 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.
  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
      value: ±10 ppm/°C
      benchmark: temperature_coefficient_of_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.
    - label: Carry current as a resistor
      value: 133 µΩ·cm
      benchmark: electrical_resistivity
      line: Hamilton prints 133 µΩ·cm at room temperature. Goodfellow prints 134 µΩ·cm for the foil grade.
    - label: Stay solid when hot
      value: 1350 °C melting point
      benchmark: melting_point
      line: Hamilton prints 1350 °C as the approximate melting point. Goodfellow prints a range of 1340 to 1390 °C.
    - label: Low thermal EMF
      value: 1.0 µV/°C against copper
      benchmark: thermal_emf_vs_copper
      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.
  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
    - label: Temperature coefficient
      benchmark: temperature_coefficient_of_resistance
    - label: Maximum use temperature
      benchmark: max_service_temp
  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.