spore: profile
id: metallic-glass
spore_version: 0.2
family: magnet-and-superconducting-alloys
name: Metallic glass (amorphous metal ribbons)
abbreviation: MG
role: amorphous magnetic core and brazing alloy
category: metals
type: magnet-alloys
summary: |
  Metallic glasses are alloys cooled so fast that they do not crystallise, which leaves a disordered atomic structure. This profile covers three commercial families read in this run. Metglas 2605SA1 is an iron-based transformer ribbon with a saturation induction of 1.56 T and a Curie temperature of 395 °C (Metglas datasheet). Metglas 2714A is a cobalt-based ribbon with a saturation induction of 0.57 T, a Curie temperature of 225 °C and near-zero magnetostriction (Metglas bulletin). MBF20 is a nickel-based brazing foil with a solidus of 969 °C and a liquidus of 1024 °C (Metglas page). A zirconium-based bulk metallic glass family, called Vitreloy here, is covered only by a yield strength from a lecture slide (1986 MPa); no density or modulus for Vitreloy was found in this run.
best_for: Tape-wound transformer and switch-mode power cores, where Metglas 2605SA1 has core loss of at most 0.17 W/kg at 60 Hz and 1.3 T, and brazing foils that join stainless steel and superalloys
weakest_at: Heat and thermal stability. The 2714A bulletin gives a continuous service temperature of 90 °C, and the ribbons crystallise at 510 °C (2605SA1) and 550 °C (2714A)
identity:
  formula: Iron-based amorphous ribbon, nominal Fe80 Si9 B11 at % for Metglas 2605SA1 (DOE/NETL core report); cobalt-based ribbon, nominal Co66 Fe4 Ni1 B15 Si14 for Metglas 2714A (Yang et al. 1997, abstract); nickel-based brazing foil MBF20, nominal Cr 7.0, Fe 3.0, Si 4.5, B 3.2 wt %, C max 0.06 wt %, balance Ni (Metglas page)
  source: netl-2605sa1-core
  where: 'Table 2, Characteristics, row Chemistry: Fe80 Si9 B11 at %'
  designations:
    - system: Trade name
      code: 2605SA1
      note: Metglas transformer core alloy
      source: metglas-2605sa1-datasheet
      where: Title block and General Properties table, row 2605SA1
    - system: Trade name
      code: 2714A
      note: Metglas Magnetic Alloy, cobalt-based
      source: metglas-2714a-bulletin
      where: 'Title block: Magnetic Alloy 2714A (cobalt-based), Technical Bulletin'
    - system: Trade name
      code: MBF20
      note: Metglas brazing foil, AWS BNi2 family
      source: metglas-brazing-foil-page
      where: Brazing alloy grades table, row MBF20
    - system: AMS
      code: '4777'
      source: metglas-brazing-foil-page
      where: 'Brazing grades table, row MBF20, AWS and AMS column: AWS BNi2, AMS 4777'
    - system: Trade name
      code: Vitreloy
      source: greer-lecture-2012
      where: Slide titled Vitreloy with 0.1 MPa hydrostatic pressure stress-strain plot
tags:
  environments: []
  applications:
    - electronics-and-chips
    - thermal-control
    - mechanisms
properties:
  - benchmark: saturation_induction
    label: Saturation induction, Metglas 2605SA1
    value: 1.56
    unit: T
    scope: material
    conditions:
      grade: Metglas 2605SA1
      temperature: not stated
      note: the datasheet says these numbers are not guaranteed
    method: General properties table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 2. General Properties and Characteristics, row 2605SA1, Saturation Induction column
  - benchmark: curie_temperature
    label: Curie temperature, Metglas 2605SA1
    value: 395
    unit: °C
    scope: material
    conditions:
      grade: Metglas 2605SA1
      note: the datasheet says these numbers are not guaranteed
    method: General properties table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 2. General Properties and Characteristics, row 2605SA1, Curie Temperature column
  - benchmark: density
    label: Density, Metglas 2605SA1
    value: 7.18
    unit: g/cm3
    scope: material
    conditions:
      grade: Metglas 2605SA1
      note: the datasheet says these numbers are not guaranteed
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 2. General Properties and Characteristics, Physical table, row 2605SA1, Density column
  - benchmark: crystallization_temperature
    label: Crystallization temperature, Metglas 2605SA1
    value: 510
    unit: °C
    scope: material
    conditions:
      grade: Metglas 2605SA1
      note: the datasheet says these numbers are not guaranteed
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 2. General Properties and Characteristics, Physical table, row 2605SA1, Crystallization Temperature column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, Metglas 2605SA1
    value: 2000
    unit: N/mm2
    scope: material
    conditions:
      grade: Metglas 2605SA1
      note: printed as 2,000 N/mm2; the datasheet says these numbers are not guaranteed
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 2. General Properties and Characteristics, Physical table, row 2605SA1, Tensile Strength column
  - benchmark: elastic_modulus
    label: Young's modulus, Metglas 2605SA1
    value: 110
    unit: GPa
    scope: material
    conditions:
      grade: Metglas 2605SA1
      note: the datasheet says these numbers are not guaranteed
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 2. General Properties and Characteristics, Physical table, row 2605SA1, Young's Modulus column
  - benchmark: hardness_vickers
    label: Vickers hardness, Metglas 2605SA1
    value: 900
    unit: HV
    scope: material
    conditions:
      grade: Metglas 2605SA1
      load: 50 g (Hv-50 g load as printed)
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 2. General Properties and Characteristics, Physical table, row 2605SA1, Vickers Hardness Hv-50 g load column
  - benchmark: cte
    label: Thermal expansion coefficient, Metglas 2605SA1
    value: 7.6
    unit: x10-6/°C
    scope: material
    conditions:
      grade: Metglas 2605SA1
      temperature_range: 30 to 300 °C
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 2. General Properties and Characteristics, Physical table, row 2605SA1, Thermal Expansion Coefficient column
  - benchmark: core_loss
    label: Core loss, Metglas 2605SA1, 60 Hz and 1.3 T
    value: 0.17
    unit: W/kg
    scope: material
    conditions:
      grade: Metglas 2605SA1 transformer core alloy
      frequency: 60 Hz
      induction: 1.3 T
      standard: ASTM A 932 (as printed)
      note: printed as an upper limit, less than or equal to 0.17
    method: Specification table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 1. Alloys and the specification, row Core Loss at 60 Hz and 1.3 T, 2605SA1 column
  - benchmark: core_loss
    label: Core loss, Metglas 2605SA1, 60 Hz and 1.4 T
    value: 0.2
    unit: W/kg
    scope: material
    conditions:
      grade: Metglas 2605SA1 transformer core alloy
      frequency: 60 Hz
      induction: 1.4 T
      standard: ASTM A 932 (as printed)
      note: printed as an upper limit, less than or equal to 0.20
    method: Specification table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 1. Alloys and the specification, row Core Loss at 60 Hz and 1.4 T, 2605SA1 column
  - benchmark: induction_60hz_80am
    label: Induction at 60 Hz and 80 A/m, Metglas 2605SA1
    value: 1.35
    unit: T
    scope: material
    conditions:
      grade: Metglas 2605SA1 transformer core alloy
      frequency: 60 Hz
      field: 80 A/m
      note: printed as a lower limit, greater than or equal to 1.35
    method: Specification table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 1. Alloys and the specification, row Induction at 60 Hz and 80 A/m, 2605SA1 column
  - benchmark: electrical_resistivity
    label: Electrical resistivity, Metglas 2605SA1
    value: 1.3
    unit: µΩm
    scope: material
    conditions:
      grade: Metglas 2605SA1
      note: printed as 1.3 µΩm; the datasheet says these numbers are not guaranteed
    method: General properties table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 2. General Properties and Characteristics, Electromagnetic table, row 2605SA1, Electrical Resistivity column
  - benchmark: magnetostriction
    label: Magnetostriction, Metglas 2605SA1
    value: 27
    unit: x10-6
    scope: material
    conditions:
      grade: Metglas 2605SA1
      note: the datasheet says these numbers are not guaranteed
    method: General properties table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 2. General Properties and Characteristics, Electromagnetic table, row 2605SA1, Magnetostriction column
  - benchmark: lamination_factor
    label: Lamination factor, Metglas 2605SA1 ribbon
    value: 84
    unit: '%'
    scope: material
    conditions:
      grade: Metglas 2605SA1 ribbon, 25 ± 4 µm thick as printed
      note: printed as a lower limit, greater than or equal to 84
    method: Ribbon dimensions and lamination factor table printed by the manufacturer
    status: ground
    source: metglas-2605sa1-datasheet
    where: 3. Ribbon Dimensions and Lamination Factor, row 2605SA1, Lamination Factor column
  - benchmark: density
    label: Density, Metglas 2714A
    value: 7.59
    unit: g/cm3
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Physical Properties, Density (g/cm3)
  - benchmark: hardness_vickers
    label: Vickers hardness, Metglas 2714A
    value: 960
    unit: HV
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
      load: 50 g (as printed)
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Physical Properties, Vicker's Hardness (50g load)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, Metglas 2714A
    value: 1
    value_high: 2
    bound: range
    unit: GPa
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Physical Properties, Tensile Strength (GPa), printed as 1-2
  - benchmark: elastic_modulus
    label: Elastic modulus, Metglas 2714A
    value: 100
    value_high: 110
    bound: range
    unit: GPa
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Physical Properties, Elastic Modulus (GPa), printed as 100-110
  - benchmark: lamination_factor
    label: Lamination factor, Metglas 2714A
    value: 75
    unit: '%'
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
      note: printed as a lower limit, greater than 75
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Physical Properties, Lamination Factor (%)
  - benchmark: cte
    label: Thermal expansion coefficient, Metglas 2714A
    value: 12.7
    unit: ppm/°C
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Physical Properties, Thermal Expansion (ppm/°C)
  - benchmark: crystallization_temperature
    label: Crystallization temperature, Metglas 2714A
    value: 550
    unit: °C
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Physical Properties, Crystallization Temperature (°C)
  - benchmark: max_service_temp
    label: Continuous service temperature, Metglas 2714A
    value: 90
    unit: °C
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
      note: printed as continuous service temperature
    method: Physical properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Physical Properties, Continuous Service Temp. (°C)
  - benchmark: saturation_induction
    label: Saturation induction, Metglas 2714A
    value: 0.57
    unit: T
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
    method: Magnetic properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Magnetic Properties, Saturation Induction (T)
  - benchmark: permeability_dc_max
    label: Maximum DC permeability, Metglas 2714A, annealed
    value: 1000000
    unit: '-'
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
      treatment: annealed
    method: Magnetic properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Magnetic Properties, Maximum D.C. Permeability, Annealed row
  - benchmark: permeability_dc_max
    label: Maximum DC permeability, Metglas 2714A, as cast
    value: 80000
    unit: '-'
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
      treatment: as cast
      note: printed as greater than 80,000
    method: Magnetic properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Magnetic Properties, Maximum D.C. Permeability, As Cast row
  - benchmark: curie_temperature
    label: Curie temperature, Metglas 2714A
    value: 225
    unit: °C
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
    method: Magnetic properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Magnetic Properties, Curie Temperature (°C)
  - benchmark: electrical_resistivity
    label: Electrical resistivity, Metglas 2714A
    value: 142
    unit: µΩ·cm
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
    method: Magnetic properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Magnetic Properties, Electrical Resistivity (µΩ.cm)
  - benchmark: magnetostriction
    label: Saturation magnetostriction, Metglas 2714A
    value: 0.5
    unit: ppm
    scope: material
    conditions:
      grade: Metglas 2714A cobalt-based ribbon
      note: printed as less than 0.5 ppm
    method: Magnetic properties table printed by the manufacturer
    status: ground
    source: metglas-2714a-bulletin
    where: Magnetic Properties, Saturation Magnetostriction (ppm)
  - benchmark: melting_point
    label: Solidus to liquidus, MBF20 brazing foil
    value: 969
    value_high: 1024
    bound: range
    unit: °C
    scope: material
    conditions:
      grade: MBF20, AWS BNi2 family, nominal composition in wt %
      note: solidus 969 °C (1776 °F) and liquidus 1024 °C (1875 °F) as printed
    method: Solidus and liquidus columns of the Metglas brazing grades table
    status: ground
    source: metglas-brazing-foil-page
    where: Brazing alloy grades table, row MBF20, Solidus and Liquidus columns
  - benchmark: yield_strength
    label: Yield or fracture strength, Vitreloy (Zr-Ti-Ni-Cu-Be)
    value: 1986
    unit: MPa
    scope: material
    conditions:
      alloy: Vitreloy, as titled on the slide (Zr-Ti-Ni-Cu-Be bulk metallic glass)
      test: tension, true stress, 0.1 MPa hydrostatic pressure
      strain: f = 0 %
      note: the slide gives the value as yield or fracture strength on one curve
    method: Value printed on a stress-strain plot in a lecture slide
    status: ground
    source: greer-lecture-2012
    where: Slide with stress-strain plot titled Vitreloy, 0.1 MPa Hydrostatic Pressure, label Yield/Fracture Strength = 1986 MPa
  - benchmark: yield_strength
    label: Yield strength, Zr51Al14.2Ni15.9Cu18.9 research bulk glass
    value: 2072.5
    unit: MPa
    scope: material
    conditions:
      alloy: Zr51Al14.2Ni15.9Cu18.9 (at %), research alloy from the Zr-Al-Ni-Cu series, not Vitreloy
      note: column sigma y in Table 1, printed without unit suffix; MPa from the column header
    method: Compression or yield value in a research paper table
    status: ground
    source: pmc-zr-bmg-series
    where: Section 2.1, Table 1, row Zr51Al14.2Ni15.9Cu18.9, sigma y column
  - benchmark: glass_transition_temperature
    label: Glass transition temperature, Zr51Al14.2Ni15.9Cu18.9 research bulk glass
    value: 725.7
    unit: K
    scope: material
    conditions:
      alloy: Zr51Al14.2Ni15.9Cu18.9 (at %), research alloy, not Vitreloy
      heating_rate: 30 K/min (table caption)
    method: Thermal analysis value in a research paper table
    status: ground
    source: pmc-zr-bmg-series
    where: Section 2.1, Table 1, row Zr51Al14.2Ni15.9Cu18.9, Tg column
corrosion:
  - environment: Uncoated ribbon in ordinary air (2714A)
    headline: Metglas lists excellent corrosion resistance for 2714A
    effect: The bulletin lists excellent corrosion resistance among the benefits. No corrosion rate, humidity or salt-spray test is printed in the bulletin.
    rating: low
    conditions:
      grade: Metglas 2714A
      exposure: not stated
      basis: manufacturer statement, no test data
    source: metglas-2714a-bulletin
    where: Benefits list, first page
  - environment: Ordinary air (2605SA1 ribbon)
    headline: No corrosion data was read for 2605SA1
    effect: The 2605SA1 datasheets give no corrosion statement or test result, so the rating is unknown until a source is read.
    rating: unknown
    conditions:
      grade: Metglas 2605SA1
      exposure: not stated
    source: metglas-2605sa1-datasheet
    where: Whole datasheet read, no corrosion section
  - environment: Brazed stainless steel joints (MBF20 foil)
    headline: Metglas claims corrosion resistance for brazed joints
    effect: The page claims high strength and corrosion resistance for the joints. No test data is printed on the page.
    rating: unknown
    conditions:
      grade: MBF20
      exposure: not stated
      basis: vendor claim, no test data
    source: metglas-brazing-foil-page
    where: Application and joining claims, vendor claims paragraph
risks:
  hazards:
    - text: PubChem notifier list for nickel gives H317, H351 and H372. Nickel is the balance of the MBF20 foil. These classes are for nickel metal, not for the foil.
      ghs:
        - H317
        - H351
        - H372
      source: pubchem-ni
      where: GHS Hazard Statements section, PubChem record for CID 935
    - text: PubChem notifier list for cobalt gives H317, H334 and H350 among its codes. These classes are for cobalt metal, not for the 2714A ribbon, which has a nominal Co66 composition in the Yang abstract.
      ghs:
        - H317
        - H334
        - H350
      source: pubchem-co
      where: GHS Hazard Statements section, PubChem record for CID 104730
  failure_risks:
    - mode: Crystallisation on overheating
      trigger: Heating near the printed crystallisation temperature
      consequence: Metglas prints a crystallisation temperature of 510 °C for 2605SA1 and 550 °C for 2714A. The values in this profile apply only to the glassy state.
      severity: high
      source: metglas-2605sa1-datasheet
      where: Physical table, Crystallization Temperature column (2714A in its bulletin, Physical Properties)
    - mode: Use above the 2714A service limit
      trigger: Continuous use above 90 °C
      consequence: Metglas prints 90 °C as the continuous service temperature for 2714A. The bulletin gives no figure for longer or peak exposures.
      severity: moderate
      source: metglas-2714a-bulletin
      where: Physical Properties, Continuous Service Temp. (°C)
    - mode: Crystallisation in a thick casting
      trigger: Cooling slower than the critical cooling rate
      consequence: Greer slides give a critical cooling rate of about 1 K/s for bulk metallic glasses, so a thick section can crystallise.
      severity: moderate
      source: greer-lecture-2012
      where: Slide Bulk Metallic Glasses, bullet on critical cooling rate
  side_effects:
    - text: At 7.59 g/cm3 for 2714A and 7.18 g/cm3 for 2605SA1, a core or foil adds mass.
      affects: Mass of a core or foil
      source: metglas-2714a-bulletin
      where: Physical Properties, Density (g/cm3)
  handling:
    - text: Anneal 2605SA1 at 370 °C for 2 hours in a magnetic field of 2400 A/m along the ribbon long axis, to release stress and induce magnetic anisotropy, as the datasheet directs.
      source: metglas-2605sa1-datasheet
      where: 4. Typical Magnetic Properties, heat treatment paragraph
    - text: NETL's core is impregnated with 100 % solids epoxy after winding.
      source: netl-2605sa1-core
      where: Table 2, Characteristics, row Impregnation
    - text: Metglas says the MBF20 foil can be stamped or cut into preforms and has unlimited shelf life.
      source: metglas-brazing-foil-page
      where: Foil form paragraph
  mitigations:
    - text: Anneal 2605SA1 in the field the datasheet specifies, and keep the core well below its 510 °C crystallisation temperature.
      source: metglas-2605sa1-datasheet
      where: 4. Typical Magnetic Properties, heat treatment paragraph and Physical table
uses:
  - application: electronics-and-chips
    device: Tape-wound power transformer cores
    example: DOE NETL built a 2605-SA1 tape-wound core, 180 by 240 by 30 mm, with a mass of 5.95 kg after impregnation.
    source: netl-2605sa1-core
    where: Table 1 core dimensions; Table 2 mass after impregnation
  - application: electronics-and-chips
    device: Switch-mode and high sensitivity transformers, and current transformers
    example: Metglas lists 2714A for switch-mode power supplies, high frequency transformers and ultra-sensitive current transformers.
    source: metglas-2714a-bulletin
    where: Applications list, first page
  - application: thermal-control
    device: Brazing foil for stainless steel and superalloy joints
    example: Metglas lists heat exchangers, aerospace parts and metallic catalytic substrates as MBF20 applications. These are vendor claims with no test data on the page.
    source: metglas-brazing-foil-page
    where: Application and joining claims, applications paragraph
  - application: mechanisms
    device: Bulk metallic glass flexspline gears for heater-free gearboxes
    example: NASA says its BMGG project has gearboxes running at surface temperatures of -173 °C (-280 °F) for heater-free designs. NTRS names the Europa Lander as the target cryogenic application.
    source: nasa-bmgg-page
    where: Project description paragraph
supply:
  - subject: Cobalt (main element of Metglas 2714A)
    producers:
      - country: Congo (Kinshasa)
        share_percent: 73
        year: 2025
      - country: Indonesia
        share_percent: 14
        year: 2025
    critical_lists: []
    recycling: 'USGS: cobalt content of purchased scrap represented 25% of estimated cobalt consumption in 2025.'
    substitutes:
      - 'USGS: substitution for cobalt could cause a loss in product performance or increased cost, depending on the application; nickel-iron alloys are listed as potential substitutes in some magnets.'
    source: usgs-mcs2026-cobalt
    where: Events, Trends, and Issues paragraph (Congo 73 %, Indonesia 14 % of world mined cobalt, 2025); Recycling and Substitutes paragraphs
  - subject: Nickel (balance of MBF20 brazing foil)
    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
    critical_lists: []
    recycling: 'USGS: in 2025 nickel recovered from scrap accounted for approximately 60% of apparent consumption, and most recycled nickel was used to produce new alloys and stainless steel.'
    substitutes: []
    source: usgs-mcs2026-nickel
    where: 'World Mine Production and Reserves table, 2025e column, metric tons of nickel content: Indonesia 2,600,000; Philippines 270,000; Russia 200,000; world total (rounded) 3,900,000. Shares calculated by Space Mushroom from these figures. Recycling paragraph.'
documents:
  - title: Metglas Amorphous transformer cores, Metglas 2605SA1 and 2605HB1M datasheet (29 April 2011)
    type: datasheet
    url: https://metglas.com/wp-content/uploads/2021/06/2605SA1-Magnetic-Alloy-Updated.pdf
    year: 2011
  - title: Metglas Magnetic Alloy 2714A (cobalt-based) Technical Bulletin
    type: datasheet
    url: https://metglas.com/wp-content/uploads/2016/12/2714A-Technical-Bulletin.pdf
    year: 2011
  - title: Metglas, Metal joining brazing foil product page with grades table
    type: datasheet
    url: https://metglas.com/metal-joining-brazing-foil/
  - title: DOE NETL, METGLAS 2605-SA1 core datasheet (June 2018)
    type: report
    url: https://netl.doe.gov/projects/files/METGLAS2605SA1core_060118.pdf
    year: 2018
  - title: Yang et al., Soft Magnetic Properties of Annealed Co-Based Amorphous Co66Fe4Ni1B15Si14 Alloy Ribbon
    type: paper
    url: https://koreascience.or.kr/article/JAKO199711920253955.page?lang=en
    year: 1997
  - title: A. L. Greer, Bulk metallic glasses, lecture 1 slides (January 2012)
    type: report
    url: https://www.icts.res.in/sites/default/files/1267685796Lindsay-Greer-Jan12-Lecture1.pdf
    year: 2012
  - title: A series of Zr-based bulk metallic glasses with room temperature plasticity (Section 2.1, Table 1)
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC5456836/
  - title: Hales and Stegall, Qualifying Bulk Metallic Glass Gear Materials for Spacecraft Applications, NASA/TP-2018-220246
    type: report
    url: https://ntrs.nasa.gov/citations/20190001052
    year: 2018
  - title: NASA, Bulk Metallic Glass Gear (BMGG) project page
    type: report
    url: https://www.nasa.gov/?p=96234
  - title: 'USGS Mineral Commodity Summaries 2026: Cobalt'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-cobalt.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Nickel'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
    year: 2026
  - title: PubChem compound record for nickel (CID 935), GHS classification
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Nickel
  - title: PubChem compound record for cobalt (CID 104730), GHS classification
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Cobalt
  - title: Wikipedia, Metallic glass
    type: report
    url: https://en.wikipedia.org/wiki/Metallic_glass
gaps:
  - Vitreloy density, Young's modulus, shear and bulk moduli, Tg and Tx were not read on any page in this run. The only Vitreloy values in the search results came from a Caltech thesis, which the host refused to serve (connection refused), and from a Springer abstract that redirected to a login page, so none is entered.
  - The nominal Vitreloy 1 composition (Zr41.2 Ti13.8 Cu12.5 Ni10 Be22.5 at %) was seen only in a patent search snippet and is not entered. The Greer slides name the family only as Zr-Ti-Ni-Cu-Be.
  - No Vitreloy hardness value was found. The Greer strength values are from a stress-strain plot under 0.1 MPa and 450 MPa hydrostatic pressure, and are not a datasheet minimum.
  - No corrosion rate, salt-spray, humidity or long-term ageing data was found for 2605SA1 or 2714A. The only statement is the Metglas bulletin claim of excellent corrosion resistance for 2714A (rated low on that basis only).
  - The Metglas brazing grades table was read as printed. The element assignments come from column order in the extracted page text, so the MBF20 composition should be checked against the full MBF20 datasheet before use.
  - MBF20 solidus and liquidus are in wt %; no atomic composition is given for any brazing foil. The ASM Alloy Digest entries for MBF-80 and MBF-20 are paywalled and were not read beyond the abstract.
  - 'Property names not in spores/property-canon.yaml (short snake_case names used): hardness_vickers, saturation_induction, permeability_dc_max, crystallization_temperature, magnetostriction, lamination_factor, induction_60hz_80am, core_loss.'
  - Iron, silicon, boron, zirconium and beryllium supply shares were not read, and no supplier shares are given. NASA NTRS names Materion as the producer of re-melt stock and Visser Precision Cast as the maker of bulk metallic glass castings for gears, with no shares.
  - Critical-mineral lists for cobalt and nickel were not checked against the final 2025 list, so critical_lists is empty for both.
  - The nickel and cobalt hazard codes are PubChem aggregated notifier lists for the metals, not classifications of the alloys. The 2714A composition Co66 Fe4 Ni1 B15 Si14 is from the Yang abstract, whose units are not printed in the abstract.
  - The NASA BMGG page gives -173 °C (-280 °F) as the surface operating temperature for gearboxes. The gear alloy is not named in the sources read, so this value is not attributed to Vitreloy.
  - Radiation, outgassing, cold welding and thermal cycling behaviour of these ribbons and foils were not looked up. No flight record was found for any of these grades.
  - The Metglas 2605SA1 ribbon and core values are typical or not guaranteed, as the datasheet says. Corrosion and long-term ageing values are missing.
  - The Metglas 2605SA1 datasheet gives the anneal of 370 °C for 2 hours in a magnetic field of 2400 A/m. That is the only anneal read, and it is not checked against a second source.
  - The Zr51Al14.2Ni15.9Cu18.9 values are from a research paper and describe a different alloy from Vitreloy. They are shown only to bracket the Zr-based family.
sources:
  metglas-2605sa1-datasheet:
    title: Metglas Amorphous Alloys for Transformer Cores, 2605SA1 and 2605HB1M datasheet (29 April 2011)
    url: https://metglas.com/wp-content/uploads/2021/06/2605SA1-Magnetic-Alloy-Updated.pdf
    kind: datasheet
    license: Manufacturer data sheet (cited, not reproduced)
  metglas-2714a-bulletin:
    title: Metglas Magnetic Alloy 2714A (cobalt-based) Technical Bulletin
    url: https://metglas.com/wp-content/uploads/2016/12/2714A-Technical-Bulletin.pdf
    kind: datasheet
    license: Manufacturer data sheet (cited, not reproduced)
  metglas-brazing-foil-page:
    title: Metglas, Metal joining brazing foil product page
    url: https://metglas.com/metal-joining-brazing-foil/
    kind: web
    license: Manufacturer web page (cited, not reproduced)
  netl-2605sa1-core:
    title: DOE NETL, METGLAS 2605-SA1 core datasheet (June 2018)
    url: https://netl.doe.gov/projects/files/METGLAS2605SA1core_060118.pdf
    kind: report
    license: US Government report (public)
  yang-co-ribbon-1997:
    title: Yang et al., Soft Magnetic Properties of Annealed Co-Based Amorphous Co66Fe4Ni1B15Si14 Alloy Ribbon
    url: https://koreascience.or.kr/article/JAKO199711920253955.page?lang=en
    kind: paper
    license: KoreaScience abstract (cited, not reproduced)
  greer-lecture-2012:
    title: Lindsay Greer, Bulk metallic glasses, lecture 1 slides (January 2012)
    url: https://www.icts.res.in/sites/default/files/1267685796Lindsay-Greer-Jan12-Lecture1.pdf
    kind: report
    license: Lecture slides (cited, not reproduced)
  pmc-zr-bmg-series:
    title: A series of Zr-based bulk metallic glasses with room temperature plasticity
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC5456836/
    kind: paper
    license: PMC open access (cited, not reproduced)
  nasa-ntrs-bmg-gear-2018:
    title: Hales and Stegall, Qualifying Bulk Metallic Glass Gear Materials for Spacecraft Applications, NASA/TP-2018-220246
    url: https://ntrs.nasa.gov/citations/20190001052
    id: NASA/TP-2018-220246
    kind: report
    license: NASA public (cited, not reproduced)
  nasa-bmgg-page:
    title: NASA, Bulk Metallic Glass Gear (BMGG) project page
    url: https://www.nasa.gov/?p=96234
    kind: report
    license: NASA public (cited, not reproduced)
  usgs-mcs2026-cobalt:
    title: 'USGS Mineral Commodity Summaries 2026: Cobalt'
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-cobalt.pdf
    year: 2026
    kind: report
    license: Public domain (USGS)
  usgs-mcs2026-nickel:
    title: 'USGS 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)
  pubchem-ni:
    title: 'PubChem compound record: Nickel (CID 935), GHS classification'
    id: CID 935
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Nickel
    kind: database
    license: PubChem (NCBI), public domain; sections attributed to ECHA and notifiers
  pubchem-co:
    title: 'PubChem compound record: Cobalt (CID 104730), GHS classification'
    id: CID 104730
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Cobalt
    kind: database
    license: PubChem (NCBI), public domain; sections attributed to ECHA and notifiers
  wikipedia-metallic-glass:
    title: 'Wikipedia: Metallic glass'
    url: https://en.wikipedia.org/wiki/Metallic_glass
    kind: report
    license: CC BY-SA (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 32
  unreachable: 2
  caveats: 4
  note: 'Values were read by an AI assistant on 2026-10-26 from the datasheets, web pages, reports and papers named in each entry. Two sources were unreachable in this run (a Caltech thesis returned connection refused and a Springer abstract redirected to a login page), so no Vitreloy density or modulus is entered. Caveats: the Metglas values are typical or not guaranteed; the Vitreloy strength is from a lecture slide and a different stress state; the Zr-Al-Ni-Cu row is a research alloy, not Vitreloy; hazard codes are for the metals.'
story:
  risk_groups:
    - title: For people
      lead: The hazard codes in the sources are for the pure metals in the alloys. No classification of the ribbons or foils themselves was found.
      level: 1
      verdict: Metal hazard codes only
      points:
        - label: Nickel as a substance
          line: PubChem notifier list for nickel gives H317 (allergic skin reaction, 100 % of notifications), H351 (suspected cancer, 100 %) and H372 (organ damage from repeated exposure, 100 %).
        - label: Cobalt as a substance
          line: PubChem notifier list for cobalt gives H317 (allergic skin reaction), H334 (allergy or asthma symptoms if inhaled) and H350 (may cause cancer) among its codes, with H317 and H334 the most widely notified.
        - label: Alloy as handled
          line: No health classification of the alloy ribbons or the MBF20 foil was found in the sources read.
    - title: If it fails
      lead: The failure routes in the sources are thermal. None of them is a flight result for these grades.
      points:
        - label: Overheating
          line: Both ribbons crystallise at a printed temperature, 510 °C for 2605SA1 and 550 °C for 2714A. The 2714A datasheet prints 90 °C as its continuous service limit.
        - label: Heavy parts
          line: At 7.59 g/cm3 for 2714A and 7.18 g/cm3 for 2605SA1 the ribbon adds mass. No Vitreloy density was read, so no mass figure is given for the Zr-based family.
    - title: Handling and storage
      points:
        - label: Anneal first
          line: The 2605SA1 datasheet anneals at 370 °C for 2 hours in a magnetic field of 2400 A/m to set the magnetic axis. Use the same anneal for the stress release the datasheet names.
        - label: Keep the foil clean
          line: Metglas describes the MBF20 foil as contaminant-free with no organic binders, and states unlimited shelf life.
  why: Metallic glasses are used where a magnetic core must lose little energy, or where a brazing foil must be ductile and stampable. The 2605SA1 datasheet gives core loss of at most 0.17 W/kg at 60 Hz and 1.3 T. Wikipedia credits Klement, Willens and Duwez at Caltech with the first reported metallic glass, Au75Si25, and says that the low magnetisation loss is used in high efficiency transformers at line frequency.
  uses:
    - where: Tape-wound power transformer cores
      line: DOE NETL built a 2605-SA1 tape-wound core of 180 by 240 by 30 mm with a mass of 5.95 kg after impregnation, and lists transformers, pulse power cores, motors and high frequency inductors as applications.
    - where: High sensitivity and switch-mode transformers
      line: Metglas lists 2714A for switch-mode power supplies, high frequency transformers, ultra-sensitive current transformers, shielding and sensors.
    - where: Brazing foil for stainless steel and superalloys
      line: Metglas says MBF20 replaces copper foil or nickel powder for brazing stainless steel, and lists aerospace, heat exchangers, catalytic substrates and preforms as uses. These are vendor claims with no test data on the page.
    - where: Cryogenic bulk metallic glass gears
      line: NASA says its BMGG project has gearboxes running at surface temperatures of -173 °C (-280 °F) for heater-free designs for missions such as a Europa Lander.
  recipe:
    line: Metglas 2605SA1 is an iron-based amorphous ribbon of nominal Fe80 Si9 B11 at %, supplied as 25 ± 4 µm foil (datasheet, DOE NETL). Metglas 2714A is cobalt-based, nominal Co66 Fe4 Ni1 B15 Si14 (Yang abstract). MBF20 is a nickel-based brazing foil, nominal Cr 7.0, Fe 3.0, Si 4.5, B 3.2 wt %, C max 0.06 wt %, balance Ni (Metglas page). Wikipedia describes melt spinning as sputtering molten metal onto a spinning metal disk.
    parts:
      - name: Iron
        symbol: Fe
        share_percent: 80
        share_note: nominal, 80 at % in 2605SA1
        role: Main element of the iron-based ribbon
        source: netl-2605sa1-core
        where: 'Table 2, Characteristics, row Chemistry: Fe80 Si9 B11 at %'
      - name: Silicon
        symbol: Si
        share_percent: 9
        share_note: nominal, 9 at % in 2605SA1
        role: Minor element, described by DOE as present in small percentages
        source: netl-2605sa1-core
        where: 'Table 2, Characteristics, row Chemistry: Fe80 Si9 B11 at %'
      - name: Boron
        symbol: B
        share_percent: 11
        share_note: nominal, 11 at % in 2605SA1
        role: Minor element, described by DOE as present in small percentages
        source: netl-2605sa1-core
        where: 'Table 2, Characteristics, row Chemistry: Fe80 Si9 B11 at %'
  can_do:
    - label: Carry flux with low loss
      value: 0.17 W/kg core loss
      benchmark: core_loss
      line: At 60 Hz and 1.3 T the 2605SA1 specification allows at most 0.17 W/kg, measured to ASTM A 932 (Metglas datasheet).
    - label: Saturate at high field
      value: 1.56 T
      benchmark: saturation_induction
      line: The 2605SA1 saturation induction is 1.56 T, and the 2714A value is 0.57 T (both Metglas datasheets).
    - label: Join stainless steel
      value: 969 to 1024 °C
      benchmark: melting_point
      line: MBF20 melts between its solidus of 969 °C and liquidus of 1024 °C (Metglas page), a range suited to brazing stainless steel.
    - label: Strength of the Zr-based glass
      value: 1986 MPa
      benchmark: yield_strength
      line: A lecture slide gives 1986 MPa yield or fracture strength for Vitreloy in tension under 0.1 MPa hydrostatic pressure (Greer).
  compare: These three families are not interchangeable. The iron-based 2605SA1 has the highest saturation induction of the ribbons read here at 1.56 T, the cobalt-based 2714A has the lowest at 0.57 T but a much higher maximum DC permeability of up to 1,000,000 when annealed (Metglas bulletin), and it is 7.59 g/cm3 and has a continuous service limit of 90 °C. The nickel-based MBF20 is a brazing foil and has no magnetic data in this profile. The zirconium-based Vitreloy family has a yield strength of 1986 MPa in one lecture figure, which is much higher than the Metglas ribbons, but no density or modulus for it was found in this run. The Curie temperatures printed for the ribbons are 395 °C for 2605SA1 and 225 °C for 2714A.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Saturation induction
      benchmark: saturation_induction
    - label: Curie temperature
      benchmark: curie_temperature
  handling:
    - Anneal the 2605SA1 ribbon at 370 °C for 2 hours in a magnetic field of 2400 A/m along the ribbon axis, as the datasheet directs.
    - Keep the 2714A ribbon below its 90 °C continuous service temperature, and avoid holding it near its 550 °C crystallisation temperature.
    - Keep the MBF20 foil free of contamination, and stamp or cut it into preforms as the page describes.
  good_for:
    - Low-loss transformer and switch-mode power cores, with 2605SA1 core loss of at most 0.17 W/kg at 60 Hz and 1.3 T.
    - High-permeability sensors and current transformers using 2714A, with maximum DC permeability of up to 1,000,000 when annealed.
    - Brazing stainless steel and superalloys with the MBF20 foil, a ductile foil that can be bent 180 degrees (Metglas page).
  watch_out:
    - 'Heat limit: 2714A has a continuous service temperature of 90 °C, and both ribbons crystallise at 510 to 550 °C.'
    - 'Vitreloy values: only a yield strength (1986 MPa) was read, and its density and modulus were not found in this run.'
    - No corrosion or ageing test data for the ribbons were read; the Metglas corrosion claim for 2714A is a manufacturer statement.
    - The NASA gear alloy is not named in the sources, so the -173 °C gearbox figure cannot be assigned to a specific composition.
  verdict: Metallic glasses are soft magnetic ribbons and brazing foils that trade a disordered structure for low core loss and easy shaping. The iron-based 2605SA1 is a transformer core with a saturation induction of 1.56 T, the cobalt-based 2714A is a high permeability sensor ribbon limited to 90 °C service, and the MBF20 foil brazes steel at about 1000 °C. The Zr-based Vitreloy family is included for its strength only, and its density and modulus were not verified in this run.