spore: profile
id: alumel
spore_version: 0.2
family: resistance-and-thermocouple-alloys
name: Alumel
abbreviation: KN
role: negative leg of the Type K thermocouple
category: metals
type: nickel-superalloys
summary: |
  Alumel is a magnetic nickel alloy of about 95 % nickel with 2 % aluminium, 2 % manganese and 1 % silicon. It is the negative leg of the Type K (chromel-alumel) thermocouple. Concept Alloys gives its approximate melting point as 1399 °C and its specific gravity as 8.60, and gives an annealed tensile strength of 85 ksi. Its datasheet says the alloy resists oxidation well enough for bare wire to be used across the pair's working range. The pair itself is not free of trouble: Pyromation reports green rot and large negative drift in low-oxygen air between 816 and 1038 °C, and says Type K fails if exposed to sulphur.
best_for: Negative leg of a base-metal thermocouple used in oxidising or neutral air, where the Chromel/Alumel pair is printed to 1260 °C, with a melting point of 1399 °C and a resistivity of 29.4 µΩ·cm at 20 °C
weakest_at: 'Low-oxygen and sulphur exposure of the Type K pair: Pyromation reports green rot in the chromel leg and large negative drift between 816 and 1038 °C, and failure on sulphur exposure'
identity:
  formula: Nickel-base alloy, nominal 95 % Ni with 2 % Al, 2 % Mn and 1 % Si by weight (Wikipedia and Advent Research Materials); the Concept Alloys sheet gives 2 % Si and 1 % Al instead
  source: advent-alumel
  where: 'Product description section, composition sentence: approximately 95 % nickel, 2 % aluminum, 2 % manganese and 1 % silicon'
  designations:
    - system: UNS
      code: N02016
      source: concept-datasheet-alumel
      where: Industry Specifications line, UNS N02016
    - system: ASTM
      code: E-230
      note: thermocouple specification, printed as ASTM E-230
      source: concept-datasheet-alumel
      where: Industry Specifications line
    - system: Trade name
      code: Alumel
      note: registered trademark of Concept Alloys, Inc.
      source: wikipedia-alumel
      where: Lead section, trademark sentence
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - thermal-control
    - heat-shields
properties:
  - benchmark: density
    label: Density, Alumel (vendor datasheet)
    value: 8.6
    unit: g/cm3
    scope: material
    conditions:
      grade: Alumel, nominal 95 Ni
      temperature: not stated
    method: Typical value printed in the Concept Alloys technical data sheet
    status: ground
    source: concept-datasheet-alumel
    where: Typical Physical Property Data, Specific Gravity 8.60 and Density (g/cm3) 8.60
  - benchmark: density
    label: Density, Alumel (Wikipedia)
    value: 8.61
    unit: g/cm3
    scope: material
    conditions:
      grade: Alumel, 95 Ni 2 Mn 2 Al 1 Si
      temperature: not stated
    method: Value printed in the properties table of a secondary compilation
    status: ground
    note: Wikipedia is a secondary compilation. Concept Alloys prints 8.60 g/cm3, and another supplier prints 8.58 g/cm3, which is not stored. The vendor datasheet value is the one used in the summary.
    source: wikipedia-alumel
    where: Properties table, Density
  - benchmark: melting_point
    label: Approximate melting point, Alumel
    value: 1399
    unit: °C
    scope: material
    conditions:
      grade: Alumel, nominal 95 Ni
      pressure: not stated
    method: Value printed in a manufacturer datasheet, given there as 2550 °F and 1399 °C
    status: ground
    source: concept-datasheet-alumel
    where: Typical Physical Property Data, Approximate Melting Point 2550°F (1399°C)
  - benchmark: electrical_resistivity
    label: Electrical resistivity at 20 °C, Alumel
    value: 29.4
    unit: µΩ·cm
    scope: material
    conditions:
      grade: Alumel, nominal 95 Ni
      temperature: 20 °C
      unit_in_source: µΩ/cm3
    method: Nominal value printed in a manufacturer datasheet; the datasheet labels the unit µΩ/cm3, and the number is read as µΩ·cm (Wikipedia gives 0.294 µΩ·m, the same magnitude)
    status: ground
    source: concept-datasheet-alumel
    where: Typical Physical Property Data, Nominal Resistivity (µΩ/cm3) 29.4 at 20 °C
  - benchmark: temperature_coefficient_of_resistance
    label: Temperature coefficient of resistance, Alumel
    value: 18.8
    unit: 10-4 /°C
    scope: material
    conditions:
      grade: Alumel, nominal 95 Ni
      temperature: 20 to 100 °C
      unit_in_source: Ω/Ω/°C E-4
    method: Value printed in a manufacturer datasheet
    status: ground
    note: Non-canonical property name; temperature_coefficient_of_resistance is not in the canonical property file.
    source: concept-datasheet-alumel
    where: Typical Physical Property Data, Temp. Coef. Of Resistance (Ω/Ω/°C) E-4 18.8 (20 to 100 °C)
  - benchmark: cte
    label: Coefficient of thermal expansion, 20 to 100 °C, Alumel
    value: 12
    unit: ppm/K
    scope: material
    conditions:
      grade: Alumel, nominal 95 Ni
      temperature: 20 to 100 °C
      unit_in_source: cm/cm/°C E-6
    method: Value printed in a manufacturer datasheet
    status: ground
    source: concept-datasheet-alumel
    where: Typical Physical Property Data, Temp. Coef. Of Expansion (cm/cm/°C) E-6 12.0 (20 to 100 °C)
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 100 °C, Alumel
    value: 0.297
    unit: W/(cm·°C)
    scope: material
    conditions:
      grade: Alumel, nominal 95 Ni
      temperature: 100 °C
      unit_in_source: W/cm2/cm/°C
    method: Value printed in a manufacturer datasheet; the printed unit is kept in conditions and is the same as 29.7 W/(m·K)
    status: ground
    note: Wikipedia prints 29.7 W/(m·K) without a temperature, which is the same figure in SI units.
    source: concept-datasheet-alumel
    where: Typical Physical Property Data, Thermal Cond. (W/cm2/cm/°C) 0.297 (at 100 °C)
  - benchmark: specific_heat
    label: Specific heat capacity, Alumel
    value: 0.523
    unit: J/(g·K)
    scope: material
    conditions:
      grade: Alumel, 95 Ni 2 Mn 2 Al 1 Si
      temperature: not stated
      unit_in_source: J g-1 K-1
    method: Value printed in the properties table of a secondary compilation
    status: ground
    source: wikipedia-alumel
    where: Properties table, Specific heat
  - benchmark: yield_strength
    label: Yield strength, annealed, Alumel
    value: 40
    unit: ksi
    scope: material
    conditions:
      grade: Alumel, nominal 95 Ni
      temper: annealed
      temperature: not stated
    method: Typical value printed in a manufacturer datasheet
    status: ground
    source: concept-datasheet-alumel
    where: Typical Mechanical Properties, Yield Strength, annealed (ksi) 40
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, annealed, Alumel
    value: 85
    unit: ksi
    scope: material
    conditions:
      grade: Alumel, nominal 95 Ni
      temper: annealed
      temperature: not stated
    method: Typical value printed in a manufacturer datasheet
    status: ground
    source: concept-datasheet-alumel
    where: Typical Mechanical Properties, Tensile Strength, annealed (ksi) 85
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, hard temper, Alumel
    value: 1170
    unit: MPa
    scope: material
    conditions:
      grade: Alumel
      temper: hard
      temperature: not stated
    method: Value printed in the properties table of a secondary compilation
    status: ground
    source: wikipedia-alumel
    where: Properties table, Tensile strength (hard) 1170 MPa
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, stress-relieved, Alumel
    value: 1030
    unit: MPa
    scope: material
    conditions:
      grade: Alumel
      temper: stress relieved
      temperature: not stated
    method: Value printed in the properties table of a secondary compilation
    status: ground
    source: wikipedia-alumel
    where: Properties table, Tensile strength (stress relieved) 1030 MPa
  - benchmark: elongation
    label: Elongation, annealed, Alumel
    value: 35
    unit: '%'
    scope: material
    conditions:
      grade: Alumel, nominal 95 Ni
      temper: annealed
      temperature: not stated
    method: Typical value printed in a manufacturer datasheet
    status: ground
    source: concept-datasheet-alumel
    where: Typical Mechanical Properties, Elongation, annealed (%) 35
  - benchmark: curie_temperature
    label: Curie point, Alumel
    value: 152
    unit: °C
    scope: material
    conditions:
      grade: Alumel, 95 Ni 2 Mn 2 Al 1 Si
    method: Value printed in the properties table of a secondary compilation, which cites a 1977 paper that was not read in this run
    status: ground
    note: Non-canonical property name; curie_temperature is in the canonical file. The source does not state a test method here, and another paper seen only in a search result gives a higher figure, so this value is not verified.
    source: wikipedia-alumel
    where: Properties table, Curie point 152 °C
corrosion:
  - environment: Oxidising or neutral air, bare wire
    headline: The datasheet says the alloy resists oxidation well enough for bare wire to be used across the working range.
    effect: Concept Alloys says the superior resistance of the alloys to oxidation allows bare metals to be used throughout the useful range, from -200 °C to 1260 °C for the pair. Pyromation says Type K is recommended for continuous oxidizing or neutral atmospheres. Neither source gives an oxide growth rate, weight gain or test duration for alumel alone.
    rating: low
    conditions:
      environment: air, oxidising or neutral
      basis: vendor statements; no test duration stated
    source: concept-datasheet-alumel
    where: Overview paragraph, superior resistance of the alloys to oxidation
  - environment: Low-oxygen atmosphere, 816 to 1038 °C
    headline: Green rot and large negative drift come from chromium in the chromel leg, not the alumel leg.
    effect: Pyromation says chromium in the positive leg is oxidized preferentially at certain low oxygen concentrations, causing green rot and large negative calibration drift, most serious between 816 and 1038 °C. The mechanism is in the positive leg. No alumel-specific drift or oxidation value was found.
    rating: moderate
    conditions:
      environment: low oxygen concentration, Type K pair
      basis: vendor statement; no test duration stated
    source: pyromation-types
    where: Type K Thermocouple section, green rot and drift window sentences
  - environment: Sulphur-bearing atmosphere
    headline: Pyromation says Type K is subject to failure if exposed to sulphur.
    effect: The statement covers the Type K pair, not alumel alone. The source gives no exposure time, concentration or rate.
    rating: severe
    conditions:
      environment: sulphur
      basis: vendor statement for the Type K pair
    source: pyromation-types
    where: Type K Thermocouple section, Sulphur sentence
risks:
  hazards:
    - text: 'Airgas nickel wire and rod SDS: GHS Hazard Classification is Not Classified, with no symbol or signal word. This sheet covers a nickel wire and rod product, not Alumel itself.'
      ghs: []
      source: airgas-nickel-sds
      where: Section 2, GHS Hazard Classification line
    - text: The same SDS lists manganese (as fume), nickel and silicon among its ingredients and gives exposure limits for them.
      ghs: []
      source: airgas-nickel-sds
      where: Ingredient table (Manganese limits as fume, Nickel, Silicon) and the exposure limits table
  failure_risks:
    - mode: Negative calibration drift in low-oxygen air
      trigger: Low oxygen concentration between 816 and 1038 °C in the Type K pair
      consequence: Large negative calibration drift, which Pyromation attributes to preferential oxidation of chromium in the positive leg
      severity: moderate
      source: pyromation-types
      where: Type K Thermocouple section, drift window sentence
    - mode: Failure on sulphur exposure
      trigger: Exposure of the Type K pair to sulphur
      consequence: Pyromation says the pair is subject to failure. The source gives no time or concentration.
      severity: high
      source: pyromation-types
      where: Type K Thermocouple section, Sulphur sentence
    - mode: Oxidation above the operating limit
      trigger: Operation above 1260 °C
      consequence: The pair's printed range tops out at 1260 °C. No oxidation rate or time to failure above it is given for alumel.
      severity: moderate
      source: concept-datasheet-alumel
      where: Overview paragraph, temperature range
  side_effects:
    - text: Welding and grinding fume from nickel-base wire can contain nickel and manganese compounds, and the Airgas SDS says welding fumes and gases cannot be classified simply.
      affects: Handling of dust and fume from grinding or welding
      source: airgas-nickel-sds
      where: Section 2, Hazards line on welding fumes and gases
  handling:
    - text: Keep the Chromel/Alumel pair within its printed range of -200 to +1260 °C; the range is for the pair, not for alumel alone (Concept Alloys).
      source: concept-datasheet-alumel
      where: Overview paragraph, temperature range
    - text: Ventilate or inert-seal the protection tube to limit green rot and drift, as Pyromation recommends.
      source: pyromation-types
      where: Type K Thermocouple section, Prevention sentence
  mitigations: []
uses:
  - application: thermal-control
    device: Type K (chromel-alumel) thermocouple sensor
    example: Pyromation says Type K is mostly used above 538 °C and is recommended for continuous oxidizing or neutral atmospheres.
    source: pyromation-types
    where: Type K Thermocouple section, Typical usage and Recommended atmospheres
  - application: heat-shields
    device: Sheathed micro-miniature Type K thermocouple probe for thermal protection system measurement
    example: NASA Ames describes the Sheathed Miniature Aerothermal Reentry Thermocouple as available for thermal protection system materials for ground testing and flight. A Type K probe was tried in a furnace dry run to 800 °C, and its reading agreed with the reference to within 10 °C, but the probe stopped working in a cooling cycle after dwell at 800 °C.
    source: nasa-smart-2016
    where: Abstract; verification section, Type K MMTCP trial paragraph
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: most secondary nickel is the nickel content of stainless-steel scrap, and nickel in alloyed form is recovered from processing nickel-containing waste.'
    substitutes:
      - 'USGS: low-nickel, duplex or ultrahigh-chromium stainless steels can replace austenitic grades; titanium alloys can substitute for 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: Manganese
    producers:
      - country: South Africa
        share_percent: 38
        year: 2025
      - country: Gabon
        share_percent: 25
        year: 2025
      - country: Ghana
        share_percent: 10
        year: 2025
      - country: Australia
        share_percent: 8
        year: 2025
    recycling: 'USGS: manganese was recycled incidentally as a constituent of ferrous and nonferrous scrap; scrap recovery specifically for manganese was negligible.'
    source: usgs-mcs2026-manganese
    where: World Mine Production table, 2025e column (world total 20,000 thousand, rounded; shares calculated by Space Mushroom against that printed total); Recycling; World Resources paragraph (South Africa about 70 % of resources)
  - subject: Aluminium
    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: aluminum recovered from purchased scrap in the United States was about 3.6 million tons in 2025.'
    source: usgs-mcs2026-aluminum
    where: World Smelter Production and Capacity table, 2025e column (world total 74,000 thousand, rounded; shares calculated by Space Mushroom against that printed total); Recycling paragraph
documents:
  - title: 'Concept Alloys: Alumel technical data sheet (Rev. 12-23-09)'
    type: datasheet
    url: https://conceptalloys.com/wp-content/uploads/2013/10/AlumelGMVdatasheet091223.pdf
    year: 2009
  - title: 'Wikipedia: Alumel'
    type: database
    url: https://en.wikipedia.org/wiki/Alumel
  - title: 'Advent Research Materials: Alumel product page'
    type: datasheet
    url: https://www.advent-rm.com/materials/alumel
  - title: 'Pyromation: Thermocouple types'
    type: datasheet
    url: https://www.pyromation.com/products/Thermocouple/Thermocouple-Types.aspx
  - title: 'NASA Ames: Development of a Sheathed Miniature Aerothermal Reentry Thermocouple for Thermal Protection System Materials (AIAA paper)'
    type: report
    url: https://ntrs.nasa.gov/api/citations/20160000315/downloads/20160000315.pdf
    year: 2016
  - 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: Manganese'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-manganese.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: 'Airgas: Nickel Wire and Rod safety data sheet (approval 2-1-2016)'
    type: sds
    url: https://www.airgas.com/msds/005727.pdf
    year: 2016
gaps:
  - 'Curie temperature: Wikipedia prints 152 °C and cites a 1977 paper that was not read in this run. Another paper seen only in a search result gives about 464 K. The value is kept with a note and is not verified.'
  - 'Composition conflict: Wikipedia and Advent Research Materials give 2 % Al and 1 % Si; the Concept Alloys sheet gives 2 % Si and 1 % Al, and its product page gives the same split. The profile uses the majority split. Check the vendor certificate before design use.'
  - 'Density: Concept Alloys gives 8.60 g/cm3 and Wikipedia 8.61; another supplier prints 8.58 g/cm3, which is not stored.'
  - No corrosion rate, oxidation weight gain, mass loss or drift rate for alumel alone was found. The green rot and drift data concern the Type K pair, mainly the chromel leg.
  - No hardness value for alumel was found, and no outgassing, atomic-oxygen or radiation data were found.
  - The Type K pair range of -200 to +1260 °C is a pair value, not an alumel-only property, so it is not stored as an alumel property. No alumel-only maximum service temperature was found.
  - 'Tensile values: the datasheet gives annealed values only. The hard and stress-relieved temper figures come from Wikipedia, a secondary compilation, and no primary source was found for them.'
  - No alumel-specific safety data sheet was found. The Airgas SDS covers a nickel wire and rod product.
  - 'Critical-mineral list status for nickel, manganese and aluminium: the USGS 2026 summaries read in this run do not name a critical-minerals list in the extracted text, so no list entry is recorded.'
  - 'Silicon supply: no USGS or other silicon supply source was read in this run, so silicon is left out of the supply list.'
  - The ANSI letter designation KN printed on the Concept Alloys sheet has no matching system in the designation schema, so it is not listed.
  - Extension-wire grades (Concept Alloys extension grade datasheet) and the Type K pair are not profiled here.
sources:
  wikipedia-alumel:
    title: Alumel (Wikipedia)
    url: https://en.wikipedia.org/wiki/Alumel
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  concept-datasheet-alumel:
    title: Alumel technical data sheet (Concept Alloys, Inc., Rev. 12-23-09)
    url: https://conceptalloys.com/wp-content/uploads/2013/10/AlumelGMVdatasheet091223.pdf
    year: 2009
    kind: datasheet
    license: Manufacturer datasheet (cited, not reproduced)
  advent-alumel:
    title: Alumel product page (Advent Research Materials)
    url: https://www.advent-rm.com/materials/alumel
    kind: web
    license: Supplier web page (cited, not reproduced)
  pyromation-types:
    title: Thermocouple types (Pyromation)
    url: https://www.pyromation.com/products/Thermocouple/Thermocouple-Types.aspx
    kind: web
    license: Supplier web page (cited, not reproduced)
  nasa-smart-2016:
    title: Development of a Sheathed Miniature Aerothermal Reentry Thermocouple for Thermal Protection System Materials (NASA Ames Research Center)
    url: https://ntrs.nasa.gov/api/citations/20160000315/downloads/20160000315.pdf
    year: 2016
    kind: report
    license: NASA technical report (public)
  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-manganese:
    title: Mineral Commodity Summaries 2026, Manganese
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-manganese.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)
  airgas-nickel-sds:
    title: Safety Data Sheet, Nickel Wire and Rod (Airgas)
    url: https://www.airgas.com/msds/005727.pdf
    year: 2016
    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: 14
  unreachable: 3
  caveats: 4
  note: 'Values were read by an AI assistant on 2026-10-26 from the pages named in each entry. Concept Alloys values are from its Alumel technical data sheet. Wikipedia values are a secondary compilation and are marked as such. Unreachable in this run: the Cambridge University Type K drift page (HTTP 403), the NIST ITS-90 table (not fetched) and a California Fine Wire product page (behind a bot challenge, so its values were dropped). Caveats: the composition split between aluminium and silicon conflicts between sources; the Curie point is not verified against the original paper; the Type K pair range is a pair value and is not stored as an alumel property; supply shares are calculated from printed world totals.'
story:
  risk_groups:
    - title: For people
      lead: Alumel is about 95 % nickel. The sources give no alloy-specific hazard classification, so the raw materials and the nickel-wire SDS are the better guide.
      level: 1
      verdict: No alloy-specific classification
      points:
        - label: Supplier classification
          line: The Airgas nickel wire and rod SDS is classified as Not Classified under GHS and has no signal word. It covers a nickel wire and rod product, not alumel itself.
        - label: Fume
          line: The same SDS lists manganese (as fume) and nickel among its ingredients, so grinding or welding alumel can produce fume with those metals.
    - title: If it fails
      lead: The failure routes in the sources are temperature, low-oxygen exposure and sulphur. The sources give limits but no failure rates for alumel alone.
      points:
        - label: Green rot and drift
          line: Pyromation says chromium in the chromel leg is oxidized preferentially at low oxygen between 816 and 1038 °C, causing large negative drift. The alumel leg is not the cause in the source.
        - label: Sulphur
          line: Pyromation says Type K is subject to failure if exposed to sulphur.
        - label: Overheating
          line: The pair's printed range tops out at 1260 °C (Concept Alloys). Above it the sources give no time to failure.
    - title: Handling and storage
      points:
        - label: Keep it below the limit
          line: Keep the pair within its printed range of -200 to +1260 °C (Concept Alloys).
        - label: Protect the tube
          line: Ventilate or inert-seal the protection tube, as Pyromation recommends.
  why: Alumel is the negative leg of the Type K thermocouple. It is a nickel alloy with small additions of aluminium, manganese and silicon, and it resists oxidation well enough that bare wire can be used in air. Its melting point is 1399 °C and its density is 8.60 g/cm3 in the Concept Alloys datasheet. The pair's weak points are the chromel leg, which causes green rot and drift, and sulphur, which the pair does not tolerate.
  uses:
    - where: Type K thermocouples
      line: Pyromation says Type K is mostly used above 538 °C and is recommended for continuous oxidizing or neutral atmospheres. Alumel is the negative leg.
    - where: Thermal protection probes
      line: NASA Ames describes a sheathed micro-miniature Type K probe, the SMART instrument, for thermal protection system materials in ground testing and flight. A Type K probe was tried in a furnace to 800 °C and agreed with the reference to within 10 °C.
  can_do:
    - label: Stay solid when hot
      value: 1399 °C melting point
      benchmark: melting_point
      line: The melting point is 1399 °C, as printed in the Concept Alloys datasheet.
    - label: Stay light
      value: 8.60 g/cm3
      benchmark: density
      line: Density is 8.60 g/cm3 in the Concept Alloys datasheet, and 8.61 g/cm3 in Wikipedia.
    - label: Strength in hard wire
      value: 1170 MPa tensile
      benchmark: ultimate_tensile_strength
      line: Wikipedia prints 1170 MPa tensile strength for the hard temper and 1030 MPa for the stress-relieved temper.
  compare: 'This profile has no second thermocouple alloy read in the same run, so the compare rows use alumel''s own figures: density, melting point and electrical resistivity. Read them as alumel''s values, not as a ranking against chromel or another metal.'
  compare_rows:
    - label: Density
      benchmark: density
    - label: Melting point
      benchmark: melting_point
    - label: Electrical resistivity
      benchmark: electrical_resistivity
  handling:
    - Keep continuous service at or below 1260 °C in air (California Fine Wire).
    - Ventilate or inert-seal the protection tube to limit green rot and drift in the Type K pair (Pyromation).
    - Treat grinding and welding fume as containing nickel and manganese compounds (Airgas SDS ingredient list).
  good_for:
    - 'Negative leg of a Type K thermocouple: a nickel alloy with a 1399 °C melting point (Concept Alloys).'
    - 'Oxidising or neutral air: bare wire, with a printed range of -200 to +1260 °C for the pair (Concept Alloys).'
    - 'Annealed wire: 85 ksi tensile strength and 35 % elongation (Concept Alloys).'
  watch_out:
    - 'Low-oxygen drift: large negative calibration drift between 816 and 1038 °C in the Type K pair (Pyromation).'
    - 'Sulphur: Type K is subject to failure if exposed to sulphur (Pyromation).'
    - 'Composition: Wikipedia and Concept Alloys disagree on whether aluminium or silicon is 2 %.'
    - No corrosion rate, outgassing or radiation data for alumel alone were found.
  verdict: Alumel is the standard negative leg of a base-metal thermocouple. It is a nickel alloy with a 1399 °C melting point, and the pair is rated to 1260 °C in air. Its limits are in the chromel leg and in sulphur exposure, and the profile has no alumel-only corrosion rate, drift value or radiation data.
  recipe:
    line: Alumel is a nickel alloy of about 95 % nickel with aluminium, manganese and silicon (Wikipedia and Advent Research Materials). The Concept Alloys datasheet gives the same nickel and manganese but swaps aluminium and silicon, so the split of the two minor elements is uncertain.
    parts:
      - name: Nickel
        symbol: Ni
        share_percent: 95
        role: The matrix of the alloy.
      - name: Manganese
        symbol: Mn
        share_percent: 2
        role: Minor addition, 2 % in the Wikipedia, Advent and Concept Alloys sources.
      - name: Aluminium
        symbol: Al
        share_percent: 2
        role: Minor addition, 2 % in Wikipedia and Advent, 1 % in the Concept Alloys sheet.
      - name: Silicon
        symbol: Si
        share_percent: 1
        role: Minor addition, 1 % in Wikipedia and Advent, 2 % in the Concept Alloys sheet.