Chromium-rich binary alloys Cr alloys

spore: profile
id: chromium-alloys
spore_version: 0.2
family: chromium-rich-binary-alloys
name: Chromium-rich binary alloys
abbreviation: Cr alloys
role: alloying and coating feedstock; chromium-iron, chromium-nickel, chromium-aluminium and chromium-titanium alloys for stainless steel, hardfacing and sputtering targets
category: metals
type: heavy-metals
summary: |
  Chromium-rich binary alloys are the chromium-iron, chromium-nickel, chromium-aluminium and chromium-titanium systems. The most-used member is ferrochrome, an iron-chromium alloy with 50 to 70 % chromium by weight, made by electric arc carbothermic reduction of chromite (Wikipedia). Over 80 % of world ferrochrome goes into stainless steel (Wikipedia). The USGS says chromium has no substitute in stainless steel or in superalloys (USGS 2026). The pure metal under these alloys has a density of 7.192 g/cm3 and a melting point of 1907 °C (Wikipedia). A cross-metal summary at this depth is not available for the Cr-Ni 50/50 hardfacing grade or the Cr-Al and Cr-Ti sputtering targets: no datasheet with a measured density or melting point was read in this run, so those rows are left as gaps.
best_for: 'Adding chromium to steel and superalloys: the USGS says chromium has no substitute in stainless steel or in superalloys, and a 12 % Cr, 4 % Ni flux-cored hardfacing wire gives 400 HB as welded (Gedik)'
weakest_at: 'Chromium loss at high temperature in wet oxygen: volatile chromium-oxy-hydroxide CrO2(OH)2 depletes the chromia scale (Sand 2022 thesis), and hexavalent chromium compounds are carcinogenic (Wikipedia, NIST)'
identity:
  formula: 'Chromium-rich binary alloys: ferrochrome (Fe-Cr, 50 to 70 % Cr by weight, Wikipedia); Cr-Ni hardfacing and sputtering targets, Cr-Al and Cr-Ti targets (compositions per supplier, see gaps)'
  source: wikipedia-ferrochrome
  where: Opening paragraph, ferrochrome definition (generally containing 50 to 70 % chromium by weight). The pure chromium CAS number 7440-47-3 is printed on the Goodfellow chromium sputtering target page and applies to the element, not to any alloy in this family.
  designations: []
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - structures
    - mechanisms
    - electronics-and-chips
properties:
  - benchmark: density
    label: Density at 20 °C, pure chromium (reference for the Cr component)
    value: 7.192
    unit: g/cm3
    scope: material
    conditions:
      grade: pure chromium metal (reference only, not an alloy)
      temperature: 20 °C
    method: Value printed in the Wikipedia infobox for chromium (the page cites a handbook for it)
    status: ground
    note: Reference for the element that makes up these alloys. It is not a value for any Cr-Ni, Cr-Al, Cr-Ti or ferrochrome alloy.
    source: wikipedia-chromium
    where: Infobox, Density (at 20° C) 7.192 g/cm3
  - benchmark: density
    label: Density at 20 °C, chromium sputtering target 99.99 %
    value: 7.1
    unit: g/cm3
    scope: material
    conditions:
      grade: pure chromium sputtering target, 99.99 % purity, 3 mm thick
      temperature: 20 °C
    method: Value printed on the supplier product page for a pure chromium sputtering target
    status: ground
    note: Goodfellow gives 7.1 g/cm3 for its pure chromium target; Wikipedia gives 7.192 g/cm3 for the element. Both are kept, and neither is an alloy value.
    source: goodfellow-cr-target
    where: Physical Properties table, Density (gcm-3) 7.1 at 20 °C
  - benchmark: melting_point
    label: Melting point, pure chromium (reference)
    value: 1907
    unit: °C
    scope: material
    conditions:
      grade: pure chromium metal (reference only, not an alloy)
      pressure: not stated
    method: Value printed in the Wikipedia infobox for chromium
    status: ground
    source: wikipedia-chromium
    where: Infobox, Melting point 2180 K (1907 °C)
  - benchmark: boiling_point
    label: Boiling point, pure chromium (Wikipedia)
    value: 2671
    unit: °C
    scope: material
    conditions:
      grade: pure chromium metal (reference only, not an alloy)
      pressure: not stated
    method: Value printed in the Wikipedia infobox for chromium
    status: ground
    note: Wikipedia gives 2671 °C and Goodfellow gives 2672 °C. Both are kept.
    source: wikipedia-chromium
    where: Infobox, Boiling point 2944 K (2671 °C)
  - benchmark: boiling_point
    label: Boiling point, pure chromium sputtering target (Goodfellow)
    value: 2672
    unit: °C
    scope: material
    conditions:
      grade: pure chromium sputtering target, 99.99 % purity
      pressure: not stated
    method: Value printed on the supplier product page for a pure chromium sputtering target
    status: ground
    source: goodfellow-cr-target
    where: Physical Properties table, Boiling point (C) 2672
  - benchmark: thermal_conductivity
    label: Thermal conductivity, pure chromium (reference)
    value: 93.9
    unit: W/(m⋅K)
    scope: material
    conditions:
      grade: pure chromium metal (reference only, not an alloy)
      temperature: not stated
    method: Value printed in the Wikipedia infobox for chromium
    status: ground
    note: Low for a metal of this density, and the page gives no temperature. It is not a value for the alloys.
    source: wikipedia-chromium
    where: Infobox, Thermal conductivity 93.9 W/(m⋅K)
  - benchmark: electrical_resistivity
    label: Electrical resistivity, pure chromium at 20 °C (reference)
    value: 125
    unit: nΩ⋅m
    scope: material
    conditions:
      grade: pure chromium metal (reference only, not an alloy)
      temperature: 20 °C
    method: Value printed in the Wikipedia infobox for chromium
    status: ground
    note: Pure chromium only. Resistive alloys made with chromium are far more resistive, for example the Ni80/Cr20 wire in the nichrome profile, so this value does not stand for those alloys.
    source: wikipedia-chromium
    where: Infobox, Electrical resistivity 125 nΩ⋅m (at 20 °C)
  - benchmark: elastic_modulus
    label: Young modulus, pure chromium (reference)
    value: 279
    unit: GPa
    scope: material
    conditions:
      grade: pure chromium metal (reference only, not an alloy)
      temperature: not stated
    method: Value printed in the Wikipedia infobox for chromium
    status: ground
    source: wikipedia-chromium
    where: Infobox, Young's modulus 279 GPa
  - benchmark: shear_modulus
    label: Shear modulus, pure chromium (reference)
    value: 115
    unit: GPa
    scope: material
    conditions:
      grade: pure chromium metal (reference only, not an alloy)
      temperature: not stated
    method: Value printed in the Wikipedia infobox for chromium
    status: ground
    source: wikipedia-chromium
    where: Infobox, Shear modulus 115 GPa
  - benchmark: chromium_content_ferrochrome
    label: Chromium content of ferrochrome by weight
    value: 50
    value_high: 70
    bound: range
    unit: '%'
    scope: material
    conditions:
      grade: ferrochrome (FeCr), general range for the alloy class
      basis: mass fraction of chromium
    method: Range printed in the Wikipedia article definition of ferrochrome
    status: ground
    note: Non-canonical property name. Canonical property file has no composition entry, so the name is chromium_content_ferrochrome and is listed in gaps.
    source: wikipedia-ferrochrome
    where: Opening paragraph, Ferrochrome alloy definition (generally containing 50 to 70 % chromium by weight)
  - benchmark: chromium_content_reference_ferrochrome
    label: Chromium mass fraction, high-carbon ferrochromium SRM 64c
    value: 68
    unit: '%'
    scope: material
    conditions:
      grade: high-carbon ferrochromium powder, NIST SRM 64c
      basis: nominal mass concentration
    method: Nominal mass concentration printed on the NIST safety data sheet for the reference powder
    status: ground
    note: Non-canonical property name. It is a nominal value for one reference powder, not a specification for all ferrochrome.
    source: nist-srm-64c
    where: Section 3, composition table, Chromium row, Nominal Mass Concentration (%) 68
  - benchmark: carbon_content_reference_ferrochrome
    label: Carbon mass fraction, high-carbon ferrochromium SRM 64c
    value: 4.7
    unit: '%'
    scope: material
    conditions:
      grade: high-carbon ferrochromium powder, NIST SRM 64c
      basis: nominal mass concentration
    method: Nominal mass concentration printed on the NIST safety data sheet for the reference powder
    status: ground
    note: Non-canonical property name. It is a nominal value for one reference powder.
    source: nist-srm-64c
    where: Section 3, composition table, Nominal Mass Concentration (%) column
  - benchmark: silicon_content_reference_ferrochrome
    label: Silicon mass fraction, high-carbon ferrochromium SRM 64c
    value: 1.22
    unit: '%'
    scope: material
    conditions:
      grade: high-carbon ferrochromium powder, NIST SRM 64c
      basis: nominal mass concentration
    method: Nominal mass concentration printed on the NIST safety data sheet for the reference powder
    status: ground
    note: Non-canonical property name. It is a nominal value for one reference powder.
    source: nist-srm-64c
    where: Section 3, composition table, Nominal Mass Concentration (%) column
  - benchmark: nickel_content_reference_ferrochrome
    label: Nickel mass fraction, high-carbon ferrochromium SRM 64c
    value: 0.43
    unit: '%'
    scope: material
    conditions:
      grade: high-carbon ferrochromium powder, NIST SRM 64c
      basis: nominal mass concentration
    method: Nominal mass concentration printed on the NIST safety data sheet for the reference powder
    status: ground
    note: Non-canonical property name. It is a nominal value for one reference powder.
    source: nist-srm-64c
    where: Section 3, composition table, Nominal Mass Concentration (%) column
  - benchmark: hardness_brinell
    label: Hardness as welded, Cr-Ni flux-cored hardfacing deposit (HARDCOR 414)
    value: 400
    unit: HB
    scope: material
    conditions:
      grade: HARDCOR 414 flux-cored wire, typical weld metal of 12 % Cr and 4 % Ni (not the 50/50 grade)
      form: as-welded deposit
    method: Typical value printed in the manufacturer datasheet for the wire
    status: ground
    note: Non-canonical property name. The value is for a 12 Cr, 4 Ni deposit, which is a different composition from 50/50 Cr-Ni.
    source: gedik-hardcor-414
    where: Mechanical Properties table, Hardness (as welded) (HB) 400
corrosion:
  - environment: Chromia-forming alloys in oxygen plus water at high temperature
    headline: Volatile chromium-oxy-hydroxide strips chromium from the chromia scale.
    effect: The Chalmers thesis (Sand 2022) reports extensive volatilization of CrO2(OH)2 from chromia-forming Ni-base alloys in high oxygen and water, which depleted chromium, triggered nickel oxidation and formed a NiO cap layer on the chromia scale. The thesis gives no corrosion rate in micrometres per year.
    rating: severe
    conditions:
      environment: high oxygen and water concentrations
      basis: laboratory exposures of alloys in the thesis; temperature not stated in the abstract
    source: sand-2022-thesis
    where: Abstract, first paragraph on high oxygen and water concentrations; Introduction paragraph on CrO2(OH)2
  - environment: Nitrogen-containing environment at low oxygen activity
    headline: A chromia scale cuts nitridation by 50 to 95 %, and an alumina scale without macro defects blocks nitrogen fully.
    effect: The Chalmers abstract reports that a chromia scale decreased nitridation by 50 to 95 % in the nitriding environment tested, and that a chromia and silica two-layered scale gave 83 to 95 %. Alumina scales without macro defects completely block the ingress of nitrogen.
    rating: moderate
    conditions:
      environment: nitriding environment with high nitrogen concentration and low oxygen activity
      basis: gravimetric and GD-OES analyses in the thesis
    source: sand-2022-thesis
    where: Abstract, nitridation paragraph
  - environment: Cr-containing alumina-forming alloys at high temperature
    headline: Alumina scales show very limited evaporation of chromium.
    effect: The Chalmers abstract says Cr-containing alloys forming alumina scales showed a very limited evaporation rate of chromium-oxy-hydroxide. This is the opposite of the chromia-forming case above.
    rating: low
    conditions:
      environment: high oxygen and water, alumina-forming alloys
      basis: exposures in the thesis
    source: sand-2022-thesis
    where: Abstract, the paragraph beginning Cr-containing alloys forming alumina scales
risks:
  hazards:
    - text: 'NIST SRM 64c safety data sheet, high-carbon ferrochromium powder: physical hazard not classified; health hazards skin sensitization category 1 (H317) and carcinogenicity category 2 (H351, suspected of causing cancer via inhalation); signal word WARNING.'
      ghs:
        - H317
        - H351
      source: nist-srm-64c
      where: Section 2, Hazards Identification, Classification, Label Elements and Hazard Statements
    - text: The same NIST sheet gives OSHA PEL 1 mg/m3 TWA and ACGIH TLV 0.5 mg/m3 TWA for chromium.
      ghs: []
      source: nist-srm-64c
      where: Section 8, Exposure Limits table, Chromium row
    - text: 'Wikipedia: chromium metal and Cr(III) ions are considered non-toxic, but chromate and its derivatives (hexavalent chromium) are toxic and carcinogenic.'
      ghs: []
      source: wikipedia-chromium
      where: Biological role, and Precautions section
  failure_risks:
    - mode: Chromium depletion from the scale in wet oxygen at high temperature
      trigger: Water vapour together with oxygen at high temperature in service
      consequence: Volatile CrO2(OH)2 removes chromium and depletes the alloy, which stops the chromia scale from protecting it (Sand 2022 thesis).
      severity: high
      source: sand-2022-thesis
      where: Abstract, first paragraph; Introduction paragraph on chromium-oxy-hydroxide
    - mode: Nitridation below the chromia scale
      trigger: Nitrogen-containing environment at low oxygen activity
      consequence: Nitrogen penetrates the scale and the alloy, which can make it brittle. A chromia scale reduces nitridation by 50 to 95 %, so the scale has to stay intact.
      severity: moderate
      source: sand-2022-thesis
      where: Abstract, nitridation paragraph; Introduction paragraph on nitrogen and carbon penetration
  side_effects:
    - text: Dust and fume from grinding or welding carry chromium and nickel compounds, and the NIST sheet lists chromium as an exposure hazard.
      affects: Handling of powder and fume from ferrochrome and hardfacing wire
      source: nist-srm-64c
      where: Section 8 exposure limits; Section 2 hazard statements
  handling:
    - text: The NIST sheet sets an exposure limit of 0.5 mg/m3 (ACGIH TLV) and 1 mg/m3 (OSHA PEL) for chromium, so exposure control is needed for powder and fume.
      source: nist-srm-64c
      where: Section 8 exposure limits table
  mitigations: []
uses:
  - application: mechanisms
    device: Hardfacing overlays on steel mill rolls, pumps and valves
    example: Gedik lists steel mill rolls, rollers, pumps and 410 stainless valves as typical base materials for its Cr-Ni flux-cored hardfacing wire (the wire deposit is 12 % Cr and 4 % Ni, not 50/50).
    source: gedik-hardcor-414
    where: Typical Base Material Grades, and Features and Applications sections
  - application: electronics-and-chips
    device: Magnetron sputtering target for thin films
    example: Goodfellow sells a 99.99 % pure chromium sputtering target for PVD and magnetron sputtering systems. Stanford Advanced Materials sells a CrAl sputtering target at 99.8 % purity or customized, made by arc melting and vacuum processing.
    source: goodfellow-cr-target
    where: Product description; purity and form table
  - application: structures
    device: Stainless steel structural and corrosion-resistant parts
    example: Over 80 % of world ferrochrome goes into stainless steel, where chromium gives corrosion resistance; the USGS says chromium has no substitute in stainless steel.
    source: wikipedia-ferrochrome
    where: Usage section
supply:
  - 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, the major strategic end use. Chromium-containing scrap can substitute for ferrochromium in some metallurgical uses.'
    net_import_reliance: 79 % of apparent consumption in 2025e (USGS)
    prices:
      - 'Ferrochromium, chromium content: 1.60 dollars per pound in 2025e (USGS)'
      - 'Chromium metal, gross weight: 5.90 dollars per pound in 2025e (USGS)'
    source: usgs-mcs2026-chromium
    where: World Mine Production and Reserves table, 2025e column (world total 51000 thousand t gross weight of chromite ore; shares calculated by Space Mushroom against that printed total; Kazakhstan value estimated by USGS); Recycling; Substitutes; Salient Statistics price rows
  - subject: Ferrochromium imports, United States (2021 to 2024)
    producers:
      - country: South Africa
        share_percent: 41
        year: 2024
      - country: Kazakhstan
        share_percent: 24
        year: 2024
      - country: Russia
        share_percent: 6
        year: 2024
    recycling: Not stated for ferrochromium in the USGS summary.
    substitutes: []
    source: usgs-mcs2026-chromium
    where: Import Sources (2021 to 24) line, Ferrochromium entry. The USGS gives the period 2021 to 2024, so the year field shows 2024 as the last year of the range.
  - subject: Aluminium (feedstock for Cr-Al targets)
    producers:
      - country: China
        share_percent: 60.8
        year: 2025
      - country: Russia
        share_percent: 5.3
        year: 2025
      - country: Canada
        share_percent: 4.5
        year: 2025
    recycling: Not read in this run.
    substitutes:
      - 'USGS: composites, magnesium, steel and titanium can substitute for aluminum in some ground-transportation uses.'
    source: usgs-mcs2026-aluminum
    where: World Smelter Production and Capacity table, 2025e column (world total 74000 thousand t; shares calculated by Space Mushroom against that printed total)
  - subject: Titanium sponge (feedstock for Cr-Ti targets)
    producers:
      - country: China
        share_percent: 70.3
        year: 2025
      - country: Japan
        share_percent: 14.3
        year: 2025
      - country: Russia
        share_percent: 6.8
        year: 2025
    recycling: 'USGS: consumption data for titanium scrap metal were limited; not quantified in this run.'
    substitutes:
      - 'USGS: few materials match titanium metal strength-to-weight ratio and corrosion resistance.'
    source: usgs-mcs2026-titanium
    where: World Sponge Metal Production table, 2025e column (world total 370000 metric t; shares calculated by Space Mushroom against that printed total); Substitutes
documents:
  - 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: Titanium'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-titanium.pdf
    year: 2026
  - title: 'Wikipedia: Ferrochrome'
    type: database
    url: https://en.wikipedia.org/wiki/Ferrochrome
  - title: 'Wikipedia: Chromium'
    type: database
    url: https://en.wikipedia.org/wiki/Chromium
  - title: 'Goodfellow: Chromium Sputtering Target, 99.99 %, 3 mm (product 1000043635)'
    type: datasheet
    url: https://www.goodfellow.com/uk/chromium-sputtering-target-1000043635
  - title: 'Stanford Advanced Materials: ST11181 Chromium Aluminum Sputtering Target (CrAl)'
    type: datasheet
    url: https://www.samaterials.com/item/st11181-chromium-aluminum-sputtering-target-cral-target.html
  - title: 'Gedik Welding: HARDCOR 414 flux-cored wire for hardfacing datasheet'
    type: datasheet
    url: https://file.gedik.com.tr/portal/approval_documents/gekatec-hardcor-414-en_628387eaf0c31.pdf
  - title: NIST Standard Reference Material 64c Ferrochromium High Carbon, safety data sheet (issued 27 July 2018)
    type: sds
    url: https://tsapps.nist.gov/srmext/msds/64c-MSDS.pdf
    year: 2018
  - title: 'Sand, T. 2022: High-Temperature Corrosion Properties of Chromia- and Alumina-Forming Alloys, PhD thesis, Chalmers University of Technology'
    type: paper
    url: https://research.chalmers.se/publication/530167/file/530167_Fulltext.pdf
    year: 2022
gaps:
  - 'Cr-Ni 50/50 hardfacing: no datasheet for a 50/50 Cr-Ni hardfacing wire or deposit was found. The Gedik HARDCOR 414 wire is a 12 Cr, 4 Ni deposit, and the search results for other Cr-Ni wires (Certilas, 13 Cr, 4 Ni and 25 Cr, 4 Ni) gave no 50/50 composition. No property of the 50/50 grade is in this file.'
  - 'Cr-Ni 50/50 sputtering target: the search results gave a melting point of 1400 °C and no density for a CrNi target, but these were generic or theoretical listings for a nickel-chromium target without a stated 50/50 composition, so they are not recorded.'
  - 'Cr-Al: the Stanford Advanced Materials page gives purity (99.8 % or customized) and process (arc melting and vacuum processing) but no composition ratio, density or melting point. Ratios of 50:50 and 70:30 at.% appear only in search snippets from other vendors and are not recorded.'
  - 'Cr-Ti: the American Elements page returned a bot-check page (Cloudflare) and could not be read. The Thin Film Materials page gives purity and a 50:50 at.% ratio as common, but no density or melting point. No Cr-Ti property value is in this file.'
  - 'Fe-Cr-Mo: not covered. The brief names Fe-Cr-Mo, but no Fe-Cr-Mo source was read in this run. Cr-Mo steels are a different family from ferrochrome.'
  - 'Non-canonical property names: hardness_brinell, chromium_content_ferrochrome, chromium_content_reference_ferrochrome, carbon_content_reference_ferrochrome, silicon_content_reference_ferrochrome and nickel_content_reference_ferrochrome are not in spores/property-canon.yaml. They are kept as short snake_case names until the canonical file adds them.'
  - 'Designations: no UNS, EN, DIN, JIS or AISI code was printed for any of these grades in the sources read, so designations is empty.'
  - Melting points of the alloys (ferrochrome, Cr-Ni, Cr-Al, Cr-Ti) were not read in this run. Only the pure element melting point was read (Wikipedia, 1907 °C).
  - Atomic weights were not read from a fetched page, so no recipe part carries atomic_weight.
  - 'Corrosion: no corrosion rate in micrometres per year and no sulphur, chloride or humidity data for these alloys. The Sand thesis gives qualitative results and percentages for nitridation only. Outgassing, atomic oxygen and radiation effects were not looked up.'
  - Ferrochrome hazard classes differ by supplier and grade. The Sigma-Aldrich high-carbon SDS (NIST64C) was seen in a search snippet as flammable solid with a DANGER signal word, which conflicts with the NIST SRM 64c sheet (no physical hazard, WARNING). The Sigma sheet was not fetched, so it is not used. The DLA ferrochromium SDS link returned an HTML page, not a PDF, and was not read.
  - 'Critical-mineral list status for chromium: the 2026 USGS chromium summary read in this run does not name a critical-minerals list, and the EU critical raw materials list was not read. No list entry is recorded.'
  - The Gedik datasheet lists operating current and voltage for 1.60 mm wire (180 to 210 A, 26 to 31 V) and a 15 kg package. These are process data and are not recorded as properties.
sources:
  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-titanium:
    title: Mineral Commodity Summaries 2026, Titanium
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-titanium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  wikipedia-ferrochrome:
    title: Ferrochrome (Wikipedia)
    url: https://en.wikipedia.org/wiki/Ferrochrome
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  wikipedia-chromium:
    title: Chromium (Wikipedia)
    url: https://en.wikipedia.org/wiki/Chromium
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  goodfellow-cr-target:
    title: Chromium Sputtering Target, 99.99 % (Goodfellow product 1000043635)
    url: https://www.goodfellow.com/uk/chromium-sputtering-target-1000043635
    kind: web
    license: Supplier product page (cited, not reproduced)
  sam-cral:
    title: ST11181 Chromium Aluminum Sputtering Target, CrAl (Stanford Advanced Materials)
    url: https://www.samaterials.com/item/st11181-chromium-aluminum-sputtering-target-cral-target.html
    kind: web
    license: Supplier product page (cited, not reproduced)
  gedik-hardcor-414:
    title: HARDCOR 414 flux cored wire for hardfacing (Gedik Welding), product datasheet
    url: https://file.gedik.com.tr/portal/approval_documents/gekatec-hardcor-414-en_628387eaf0c31.pdf
    kind: datasheet
    license: Manufacturer datasheet (cited, not reproduced)
  nist-srm-64c:
    title: Safety Data Sheet, SRM 64c Ferrochromium High Carbon (NIST), issued 27 July 2018
    url: https://tsapps.nist.gov/srmext/msds/64c-MSDS.pdf
    year: 2018
    kind: datasheet
    license: US government safety data sheet (cited, not reproduced)
  sand-2022-thesis:
    title: High-Temperature Corrosion Properties of Chromia- and Alumina-Forming Alloys (Sand, Chalmers PhD thesis)
    url: https://research.chalmers.se/publication/530167/file/530167_Fulltext.pdf
    year: 2022
    kind: paper
    license: Chalmers thesis (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 15
  unreachable: 1
  caveats: 4
  note: 'Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. The pure chromium reference values are for the element, not for the alloys in this family. The Cr-Ni 50/50, Cr-Al and Cr-Ti properties are not in the file. The American Elements Cr-Ti page could not be read (bot-check page). Caveats: the chromium shares are calculated from printed mine production (gross weight of chromite ore), the aluminium and titanium shares are calculated from printed world totals, and the corrosion ratings are the profile reading of the Sand thesis, not a published rating.'
story:
  risk_groups:
    - title: For people
      lead: Chromium metal and Cr(III) are considered non-toxic, but hexavalent chromium is carcinogenic, and the high-carbon ferrochrome reference powder is a skin sensitizer and suspected carcinogen.
      level: 1
      verdict: 'Ferrochrome: sensitizer and suspected carcinogen'
      points:
        - label: Ferrochromium SDS
          line: The NIST SRM 64c sheet for high-carbon ferrochromium powder gives H317 (skin sensitization category 1) and H351 (suspected of causing cancer via inhalation, category 2), with the signal word WARNING.
        - label: Exposure limits
          line: The same sheet gives 1 mg/m3 (OSHA PEL) and 0.5 mg/m3 (ACGIH TLV) for chromium.
        - label: Hexavalent chromium
          line: Wikipedia says chromate and its derivatives are toxic and carcinogenic, unlike the metal and Cr(III) ions.
    - title: If it fails
      lead: The failure routes in the sources are chromium loss in wet oxygen and nitrogen ingress when the chromia scale is damaged.
      points:
        - label: Volatile chromium loss
          line: In high oxygen and water, chromia-forming Ni-base alloys lost chromium by volatilization of CrO2(OH)2, which depleted the alloy (Sand 2022 thesis).
        - label: Nitrogen ingress
          line: A chromia scale reduced nitridation by 50 to 95 %, so a damaged scale lets nitrogen into the alloy.
    - title: Handling and storage
      points:
        - label: Control dust and fume
          line: Control powder and fume from ferrochrome and hardfacing wire, because the NIST sheet lists chromium exposure limits.
  why: Chromium-rich binary alloys are used because chromium gives corrosion resistance and hardness. Ferrochrome (50 to 70 % Cr) is the main feed for stainless steel. The Gedik hardfacing wire deposit is 400 HB as welded. The pure metal under these alloys is dense (7.192 g/cm3) and melts at 1907 °C. The weak points are that volatile chromium compounds form in wet oxygen at high temperature, and that hexavalent chromium is a carcinogen.
  uses:
    - where: Hardfacing overlays
      line: The Gedik HARDCOR 414 flux-cored wire, with 12 % Cr and 4 % Ni in the deposit, is for hardfacing steel mill rolls, pumps and valves, and gives 400 HB as welded.
    - where: Sputtering targets
      line: Goodfellow sells a 99.99 % chromium sputtering target for PVD and magnetron sputtering. Stanford Advanced Materials sells a CrAl target at 99.8 % purity or customized.
    - where: Stainless steel
      line: Over 80 % of world ferrochrome goes into stainless steel, where chromium gives the corrosion resistance (Wikipedia).
  can_do:
    - label: Resist oxidation with a chromia scale
      value: 93.9 W/(m⋅K)
      benchmark: thermal_conductivity
      line: The pure metal conducts heat at 93.9 W/(m⋅K) (Wikipedia, temperature not stated). Chromia scales resist oxidation, and the Sand thesis shows a chromia scale cuts nitridation by 50 to 95 %.
    - label: Stay solid when hot
      value: 1907 °C melting point
      benchmark: melting_point
      line: The pure metal melts at 1907 °C (Wikipedia). The alloy melting points were not read in this run.
    - label: Carry a hard wear layer
      value: 400 HB as welded
      benchmark: hardness_brinell
      line: The Gedik 12 Cr, 4 Ni flux-cored deposit is 400 HB as welded. This is not the 50/50 Cr-Ni grade.
  compare: These compare rows use the pure chromium reference values for density, melting point and thermal conductivity, because the alloy values for the Cr-Ni 50/50, Cr-Al and Cr-Ti grades were not read in this run. Read them as the element, not as a ranking of the alloys.
  compare_rows:
    - label: Density, pure Cr reference
      benchmark: density
    - label: Melting point, pure Cr reference
      benchmark: melting_point
    - label: Thermal conductivity, pure Cr reference
      benchmark: thermal_conductivity
  handling:
    - Keep ferrochrome and hardfacing powder and fume below the 0.5 mg/m3 ACGIH TLV for chromium (NIST SRM 64c sheet).
    - Check the SDS for the exact ferrochrome grade and supplier, because classifications differ by carbon content and supplier.
    - Keep wet oxygen and high temperature away from chromia-forming alloys where possible, since chromium is lost as volatile CrO2(OH)2 (Sand 2022).
  good_for:
    - 'Stainless steel feed: over 80 % of ferrochrome goes into stainless steel, and the USGS says chromium has no substitute in it.'
    - 'Hardfacing: 400 HB as welded for the Gedik 12 Cr, 4 Ni flux-cored deposit.'
    - 'Sputtering targets: 99.99 % pure chromium and 99.8 % CrAl targets are sold for PVD (Goodfellow, Stanford Advanced Materials).'
  watch_out:
    - 'Hexavalent chromium: the NIST sheet for ferrochrome powder gives H351, suspected of causing cancer via inhalation.'
    - 'Wet oxygen at high temperature: volatile CrO2(OH)2 depletes chromia-forming alloys (Sand 2022).'
    - 'Supplier classification varies: the NIST SRM 64c sheet and a Sigma-Aldrich sheet seen in search do not give the same hazard class.'
    - No Cr-Ni 50/50, Cr-Al or Cr-Ti property value is in this file; see gaps.
  verdict: Chromium-rich binary alloys are the feed for stainless steel and a source of hard, corrosion-resistant overlays and sputtering targets. The pure metal is dense (7.192 g/cm3) and melts at 1907 °C. The 50/50 Cr-Ni, Cr-Al and Cr-Ti grades have no sourced density or melting point in this file, and the Fe-Cr-Mo family is not covered. Ferrochrome and its powders carry skin-sensitization and carcinogenicity classifications.
  recipe:
    line: Chromium-rich binary alloys are not one composition. Ferrochrome (Fe-Cr) contains 50 to 70 % chromium by weight and is made by electric arc carbothermic reduction of chromite (Wikipedia). The reference ferrochromium powder NIST SRM 64c is given in the parts below, as nominal mass concentrations. The Cr-Ni 50/50, Cr-Al and Cr-Ti compositions are not read in this run.
    parts:
      - name: Chromium
        symbol: Cr
        share_percent: 68
        role: Main alloying element; ferrochrome generally contains 50 to 70 % Cr (Wikipedia)
      - name: Iron
        symbol: Fe
        share_percent: 25
        role: Matrix element of ferrochrome
      - name: Carbon
        symbol: C
        share_percent: 4.7
        role: Carbon from the carbothermic reduction, high-carbon grade
      - name: Silicon
        symbol: Si
        share_percent: 1.22
        role: Minor element in the reference grade
      - name: Nickel
        symbol: Ni
        share_percent: 0.43
        role: Trace element in the reference grade