spore: profile
id: gold-germanium
spore_version: 0.2
family: precious-metals
name: Gold-germanium eutectic (Au88Ge12)
abbreviation: AuGe
role: eutectic brazing and die-attach alloy for electronic parts and hermetic seals
category: metals
type: precious-metals
summary: 'Au88Ge12 is the gold-germanium eutectic alloy, about 88 atomic percent gold and 12 atomic percent germanium, sold as as-rolled foil and sheet. Lucas-Milhaupt prints its liquidus and solidus both at 356 °C for PREMABRAZE 880. Suppliers disagree on the melting point: a Goodfellow table prints 340-350 °C and a Goodfellow article prints 361 °C for the eutectic reaction. The Goodfellow datasheet prints a thermal conductivity of 44 W m-1 K-1 at 23 °C and a tensile strength of 185 MPa in the as-rolled temper.'
best_for: Brazing and die attach of electronic parts in vacuum or a controlled atmosphere, where a melting point near 356 °C and a low vapor pressure filler metal are needed (Lucas-Milhaupt)
weakest_at: 'Thin evidence base: the melting point, density, thermal conductivity and tensile strength are each printed with different values by different suppliers, and no hardness number and no space test was found'
identity:
  formula: 'Au88Ge12: gold-germanium eutectic alloy, nominal Gold 88.00 and Germanium 12.00 (Lucas-Milhaupt); about 88 atomic percent gold and 12 atomic percent germanium (Goodfellow material article)'
  source: lucas-premabraze
  where: Product Details, row Nominal Composition; the atomic-percent wording is in the Goodfellow material article, Introduction
  designations:
    - system: UNS
      code: P00370
      source: goodfellow-product
      where: Properties common to all products in this list, row UNS Number
    - system: Trade name
      code: PREMABRAZE 880
      source: lucas-premabraze
      where: Product Details, row Name
tags:
  environments: []
  stresses: []
  applications:
    - electronics-and-chips
properties:
  - benchmark: melting_point
    label: Liquidus, PREMABRAZE 880
    value: 356
    unit: °C
    scope: material
    conditions:
      composition: nominal Gold 88.00, Germanium 12.00 as printed
      basis: liquidus row of the product details table
    method: Value printed in a manufacturer product details table; the same row also prints 673 °F
    status: ground
    source: lucas-premabraze
    where: 'Product Details, row Liquidus: 673 °F, 356 °C'
  - benchmark: melting_point
    label: Solidus, PREMABRAZE 880
    value: 356
    unit: °C
    scope: material
    conditions:
      composition: nominal Gold 88.00, Germanium 12.00 as printed
      basis: solidus row of the product details table
    method: Value printed in a manufacturer product details table; the same row also prints 673 °F
    status: ground
    source: lucas-premabraze
    where: 'Product Details, row Solidus: 673 °F, 356 °C'
  - benchmark: melting_point
    label: Eutectic reaction temperature
    value: 361
    unit: °C
    scope: material
    conditions:
      composition: Au-Ge eutectic, as described in the article
    method: Value printed in a manufacturer materials article
    status: ground
    note: The same paragraph says the 88/12 ratio gives an optimized melting point of 356 °C, so the article prints both 361 °C and 356 °C.
    source: goodfellow-material
    where: Material Overview section, sentence beginning The eutectic reaction occurs at 361 °C
  - benchmark: melting_point
    label: Melting point range, Goodfellow datasheet table
    value: 340
    value_high: 350
    bound: range
    unit: °C
    scope: material
    conditions:
      composition: Au 88 / Ge 12
      form: foil or sheet, as rolled
    method: Range printed in a manufacturer datasheet table
    status: ground
    note: This table prints 340-350 °C, but the Goodfellow product description gives about 356 °C, so the two supplier values disagree.
    source: goodfellow-tds
    where: Thermal Properties table, row Melting point( C ), entry 340-350
  - benchmark: max_brazing_temperature
    label: Maximum recommended brazing temperature
    value: 412
    unit: °C
    scope: material
    conditions:
      process: brazing, as printed by the supplier
      heating_methods: controlled atmosphere or vacuum
    method: Process limit printed in a manufacturer product details table
    status: ground
    source: lucas-premabraze
    where: 'Product Details, row Max Recommended Brazing Temperature: 773 °F, 412 °C'
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 23 °C
    value: 44
    unit: W m-1 K-1
    scope: material
    conditions:
      temperature: 23 °C
      composition: Au 88 / Ge 12
      form: foil or sheet
    method: Value printed in a manufacturer datasheet table
    status: ground
    note: The Goodfellow article gives approximately 30 W m-1 K-1 with no temperature; the two figures are kept side by side and not reconciled.
    source: goodfellow-tds
    where: Thermal Properties table, row Thermal conductivity( W m-1 K-1 ), entry 44@23°C
  - benchmark: thermal_conductivity
    label: Thermal conductivity, approximate value in the article
    value: 30
    unit: W m-1 K-1
    scope: material
    conditions:
      temperature: not stated
      composition: Au-Ge eutectic
    method: Approximate value printed in a manufacturer materials article
    status: ground
    note: The article gives this value as approximate and with no temperature; the datasheet prints 44 at 23 °C.
    source: goodfellow-material
    where: Material Overview section, sentence stating a thermal conductivity of approximately 30 W m-1 K-1
  - benchmark: cte
    label: Coefficient of thermal expansion, 20 to 100 °C
    value: 13
    unit: ppm/K
    scope: material
    conditions:
      temperature_range: 20 to 100 °C
      composition: Au 88 / Ge 12
      unit_in_source: x10-6 K-1 as printed in the table header (equal to ppm/K)
    method: Value printed in a manufacturer datasheet table; the printed unit x10-6 K-1 is the same as ppm/K
    status: ground
    source: goodfellow-tds
    where: Thermal Properties table, row Coefficient of thermal expansion, entry 13@20-100°C
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, as-rolled foil or sheet
    value: 185
    unit: MPa
    scope: material
    conditions:
      temper: As Rolled (per the Goodfellow product page)
      form: foil or sheet
      composition: Au 88 / Ge 12
    method: Value printed in a manufacturer datasheet table
    status: ground
    source: goodfellow-tds
    where: Mechanical Properties table, row Tensile strength( MPa ), entry 185
  - benchmark: density
    label: Density, as printed in the safety data sheet
    value: 18
    unit: g/cm3
    scope: material
    conditions:
      basis: SDS states that properties in Section 9 are at standard temperature and pressure unless otherwise indicated
    method: Value printed in a supplier safety data sheet
    status: ground
    note: The Wesgo datasheet prints a different density for the same 88/12 alloy (14.7 Mg/m3, see the next row); both are kept side by side and not reconciled.
    source: goodfellow-sds
    where: 'Section 9, Physical and chemical properties, row Density : 18 g/cm³'
  - benchmark: density
    label: Density, Wesgo GEORO datasheet
    value: 14.7
    unit: Mg/m3
    scope: material
    conditions:
      composition: nominal 88% Au and 12% Ge by weight, as printed
      form: not stated in the datasheet
      basis: values are based on test pieces and are indicative only, as the datasheet says
    method: Value printed in a manufacturer datasheet, Physical Properties table; the sheet says values are not guaranteed
    status: ground
    note: Disagrees with the 18 g/cm3 safety-data-sheet value above; the two figures are kept side by side.
    source: wesgo-georo
    where: Physical Properties table, row Density, entry 14.7 Mg/m³ (0.531 lb/in³)
  - benchmark: yield_strength
    label: Yield strength (0.2% offset), Wesgo GEORO datasheet
    value: 168
    unit: MPa
    scope: material
    conditions:
      offset: 0.2%
      composition: nominal 88% Au and 12% Ge by weight, as printed
      form: not stated in the datasheet
      temper: not stated in the datasheet
      basis: test pieces, indicative only, as the datasheet says
    method: Value printed in a manufacturer datasheet, Physical Properties table
    status: ground
    source: wesgo-georo
    where: Physical Properties table, row Yield Strength (0.2% offset), entry 168 MPa (24.4 x 103 lb/in²)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, Wesgo GEORO datasheet
    value: 202
    unit: MPa
    scope: material
    conditions:
      composition: nominal 88% Au and 12% Ge by weight, as printed
      form: not stated in the datasheet
      temper: not stated in the datasheet
      basis: test pieces, indicative only, as the datasheet says
    method: Value printed in a manufacturer datasheet, Physical Properties table
    status: ground
    note: The Goodfellow datasheet prints 185 MPa for as-rolled foil or sheet; the two figures are kept side by side and not reconciled.
    source: wesgo-georo
    where: Physical Properties table, row Tensile Strength, entry 202 MPa (29.3 x 103 lb/in²)
  - benchmark: elongation
    label: Elongation, 2 in (50 mm) gage section, Wesgo GEORO datasheet
    value: 2
    unit: '%'
    scope: material
    conditions:
      gage_section: 2 in / 50 mm
      composition: nominal 88% Au and 12% Ge by weight, as printed
      form: not stated in the datasheet
      basis: test pieces, indicative only, as the datasheet says
    method: Value printed in a manufacturer datasheet, Physical Properties table
    status: ground
    source: wesgo-georo
    where: Physical Properties table, row Elongation (2in/50mm gage section), entry 2%
corrosion:
  - environment: Supplier statement on corrosion resistance (no test conditions printed)
    headline: The supplier claims excellent corrosion resistance for Au88Ge12; no measured corrosion rate was found in any source we hold.
    effect: Goodfellow's product page says the foil exhibits excellent corrosion resistance, stable electrical conductivity, and superior wettability on nickel and gold. It gives no test, environment or duration, so the claim is a vendor statement.
    rating: low
    conditions:
      basis: vendor statement, no environment, humidity, temperature or duration printed
      composition: Au88/Ge12
    source: goodfellow-product
    where: Product description, first paragraph
  - environment: Supplier statement on oxidation resistance in harsh environments (no test conditions printed)
    headline: The supplier claims oxidation resistance for long-term use; the claim has no test data behind it in the sources we hold.
    effect: Goodfellow's material article says the oxidation resistance ensures long-term durability in harsh environments. It names no environment, temperature or duration, so this is also a vendor claim.
    rating: low
    conditions:
      basis: vendor statement, no test printed
      composition: Au-Ge eutectic
    source: goodfellow-material
    where: Material Overview section, paragraph on chemical stability
risks:
  hazards:
    - text: Goodfellow's safety data sheet for product AU040 (version 0.12, issued 01/03/2024) says the material is not classified under GHS, has no signal word and no hazard statements, and is not considered hazardous under the OSHA Hazard Communication Standard. Its toxicology entries read Not available.
      ghs: []
      source: goodfellow-sds
      where: Section 2 (Hazards identification) and Section 11 (Toxicological information)
    - text: 'PubChem lists elemental germanium with notified hazard codes: H228 (flammable solid), H361 (suspected of damaging fertility or the unborn child), H373 (may cause damage to organs through prolonged or repeated exposure) and H412 (harmful to aquatic life with long lasting effects). These codes are for germanium metal, not for the eutectic alloy, and 186 of 319 reports say germanium does not meet GHS criteria.'
      ghs:
        - H228
        - H361
        - H373
        - H412
      source: pubchem-germanium
      where: GHS Classification (CID 6326954), hazard statements and ECHA C&L notifications summary
    - text: PubChem says gold does not meet GHS hazard criteria in 502 of 506 reports.
      ghs: []
      source: pubchem-gold
      where: GHS Classification (CID 23985)
  failure_risks:
    - mode: Brazing above the maximum recommended temperature
      trigger: Heating the joint above 412 °C
      consequence: The supplier prints 412 °C as the maximum recommended brazing temperature and states no consequence of exceeding it.
      severity: moderate
      source: lucas-premabraze
      where: Product Details, row Max Recommended Brazing Temperature
  side_effects: []
  handling:
    - text: Store in the original container, protected from direct sunlight, in a dry, cool and well-ventilated area away from incompatible materials, and keep the container tightly closed until use.
      source: goodfellow-sds
      where: Section 7 (Handling and storage)
    - text: Use good general ventilation, and wear safety eyewear with side shields where a risk assessment requires it.
      source: goodfellow-sds
      where: Section 8 (Exposure controls and personal protection)
  mitigations:
    - text: Dispose of surplus and non-recyclable material through a licensed waste disposal contractor.
      source: goodfellow-sds
      where: Section 13 (Disposal considerations)
uses:
  - application: electronics-and-chips
    device: Die attach and brazing layers for microelectronic parts
    example: Goodfellow says the foil provides uniform brazing layers for die attach, MEMS packaging, and hermetic assemblies.
    source: goodfellow-tds
    where: Product description, first paragraph
  - application: electronics-and-chips
    device: Soldering of electronic components that need a low vapor pressure filler metal
    example: Lucas-Milhaupt says typical applications include soldering of electronic components requiring low vapor pressure filler metal.
    source: lucas-premabraze
    where: Product Overview
  - application: electronics-and-chips
    device: Hermetic optoelectronic modules and cryogenic device assembly
    example: Goodfellow's product page lists hermetic optoelectronic modules, precision MEMS packaging, and cryogenic device assembly among its applications.
    source: goodfellow-product
    where: Product description, third paragraph
supply:
  - subject: Gold
    producers:
      - country: China
        share_percent: 11.5
        year: 2025
      - country: Russia
        share_percent: 9.4
        year: 2025
      - country: Australia
        share_percent: 8.5
        year: 2025
      - country: Canada
        share_percent: 6.1
        year: 2025
      - country: United States
        share_percent: 4.8
        year: 2025
    critical_lists: []
    recycling: 'USGS: an estimated 90 tons of new and old scrap was recycled in 2025, equivalent to about 60% of reported consumption.'
    substitutes:
      - 'USGS: generally, palladium, platinum, and silver may substitute for gold.'
    source: usgs-mcs2026-gold
    where: 'World Mine Production and Reserves table, 2025e column: China 380, Russia 310, Australia 280, Canada 200 and United States 160 tons; shares calculated by Space Mushroom against the printed world total of 3,300 tons. Recycling and Substitutes sections. Critical-list status was not confirmed from a source we hold.'
  - subject: Germanium
    abundance: 'USGS: most producers do not publicly report germanium production, so world production shares are not published; China is the leading producer of germanium metal. US import sources for germanium metal over 2021 to 2024 were China 41%, Belgium 27% and Germany 25%.'
    producers: []
    critical_lists: []
    recycling: 'USGS: the United States can recycle new and old germanium scrap, and machining scrap from infrared optics is routinely recycled.'
    substitutes:
      - 'USGS: silicon or gallium arsenide substitute for germanium in certain electronic applications.'
    source: usgs-mcs2026-germanium
    where: Domestic Production and Use; Import Sources (2021-24); Recycling; World Refinery Production and Reserves; Substitutes
media: []
documents:
  - title: Goodfellow safety data sheet, Gold/Germanium Eutectic, product AU040, version 0.12
    type: sds
    url: https://www.goodfellow.com/usa/safety-data-sheet/download/pdf/AU040
    year: 2024
  - title: Goodfellow technical data sheet, Gold-Germanium Eutectic Foil/Sheet (Au88-Ge12)
    type: datasheet
    url: https://www.goodfellow.com/usa/technical_data/pdf/download?sku=1000034432-group
  - title: 'USGS Mineral Commodity Summaries 2026: Germanium'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-germanium.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Gold'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-gold.pdf
    year: 2026
  - title: 'PubChem: Germanium (CID 6326954), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/6326954
    year: 2026
  - title: 'PubChem: Gold (CID 23985), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/23985
    year: 2026
  - title: Georo data sheet, gold-germanium vacuum brazing alloy, 88% Au and 12% Ge (Wesgo, Morgan Advanced Materials)
    type: datasheet
    url: https://www.morgantechnicalceramics.com/media/yosagllg/wesgo_georo_technical-data-sheet-2018.pdf
    year: 2018
gaps:
  - 'Critical-mineral list status for gold and germanium is not confirmed: the USGS 2025 list page opened without its list text, so critical_lists is empty for both.'
  - No peer-reviewed Au-Ge phase diagram or eutectic paper was added; web search reached its per-turn limit before one could be found.
  - No EN, DIN, ASTM, AMS or JIS designation was printed by any source we hold. Only the UNS code P00370 (Goodfellow) and the trade name PREMABRAZE 880 (Lucas-Milhaupt) are listed.
  - 'Melting point differs across suppliers: 340-350 °C (Goodfellow datasheet table), 356 °C (Lucas-Milhaupt liquidus and solidus, and the Goodfellow product description) and 361 °C (Goodfellow article, eutectic reaction). All three are kept with their sources.'
  - 'Thermal conductivity differs: 44 W m-1 K-1 at 23 °C (Goodfellow datasheet) against approximately 30 W m-1 K-1 with no temperature (Goodfellow article). Both are kept.'
  - 'Electrical resistivity is not recorded: the Goodfellow article prints a value with a garbled unit.'
  - 'Density disagrees across sources: 18 g/cm3 (Goodfellow safety data sheet, Section 9) against 14.7 Mg/m3 (Wesgo Georo datasheet, Physical Properties). Both are kept and not reconciled.'
  - 'Tensile strength disagrees across sources: 185 MPa (Goodfellow datasheet, as-rolled foil or sheet) against 202 MPa (Wesgo Georo datasheet, form and temper not stated). Both are kept.'
  - Yield strength (168 MPa) and elongation (2%) come from one source only, the Wesgo Georo datasheet, which prints no form or temper.
  - 'Hardness: the Goodfellow article describes a hardness and ductility balance but prints no number.'
  - Specific heat and Young's modulus were not found in any source we hold. A search snippet pointed to a materials page for AuGe12 that was not fetched, so no value from it is used.
  - max_brazing_temperature is not a canonical name in property-canon.yaml and needs canon review.
  - Corrosion and oxidation resistance are supplier claims. No measured corrosion or oxidation rate for Au88Ge12 was found in any source we hold.
  - No space qualification, flight, vacuum outgassing or radiation result was found for Au88Ge12.
  - No tabulated comparison values for other solders were found, so the compare text makes no numeric ranking.
  - Germanium world production shares are not published in the USGS summary. The US import shares are given in the supply text, not as producer shares.
  - Atomic weights for gold and germanium were not recorded, so the recipe gives shares only.
  - The Lucas-Milhaupt page prints no UNS, EN or AMS code, so the standard code for this alloy is not listed.
sources:
  lucas-premabraze:
    title: PREMABRAZE 880 product page (Lucas-Milhaupt)
    url: https://www.lucasmilhaupt.com/EN/Products/PREMABRAZE-880.htm
    kind: web
    license: supplier web page, linked not reproduced
  goodfellow-product:
    title: Gold-Germanium Eutectic Foil/Sheet (Au88-Ge12), product page (Goodfellow)
    url: https://www.goodfellow.com/usa/gold-germanium-eutectic-alloy-foil-au88-ge12-group
    kind: web
    license: supplier web page, linked not reproduced
  goodfellow-tds:
    title: Goodfellow technical data sheet, Gold-Germanium Eutectic Foil/Sheet (Au88-Ge12), SKU 1000034432-group
    url: https://www.goodfellow.com/usa/technical_data/pdf/download?sku=1000034432-group
    kind: datasheet
    license: supplier document, linked not reproduced
  goodfellow-material:
    title: Gold/Germanium Eutectic (Au88/Ge12), Material Information (Goodfellow resources article)
    url: https://www.goodfellow.com/usa/resources/gold-germanium-eutectic-au88-ge12-material-information/
    kind: web
    license: supplier web page, linked not reproduced
  goodfellow-sds:
    title: Safety data sheet, Gold/Germanium Eutectic, product AU040, version 0.12 (Goodfellow)
    url: https://www.goodfellow.com/usa/safety-data-sheet/download/pdf/AU040
    kind: datasheet
    year: 2024
    license: supplier document, linked not reproduced
  usgs-mcs2026-germanium:
    title: Mineral Commodity Summaries 2026, Germanium
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-germanium.pdf
    kind: report
    year: 2026
    license: public domain (USGS)
  usgs-mcs2026-gold:
    title: Mineral Commodity Summaries 2026, Gold
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-gold.pdf
    kind: report
    year: 2026
    license: public domain (USGS)
  pubchem-germanium:
    title: PubChem compound summary, Germanium (CID 6326954), GHS classification
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/6326954/JSON
    kind: database
    year: 2026
    license: public domain (NIH PubChem)
  pubchem-gold:
    title: PubChem compound summary, Gold (CID 23985), GHS classification
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23985/JSON
    kind: database
    year: 2026
    license: public domain (NIH PubChem)
  wesgo-georo:
    title: Georo data sheet, gold-germanium vacuum brazing alloy, 88% Au and 12% Ge (Wesgo, Morgan Advanced Materials)
    url: https://www.morgantechnicalceramics.com/media/yosagllg/wesgo_georo_technical-data-sheet-2018.pdf
    kind: datasheet
    year: 2018
    license: manufacturer data sheet, linked not reproduced
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 14
  unreachable: 1
  caveats: 4
  note: 'Written by an AI assistant on 2026-11-01 from pages and PDFs read in that session: 14 property values across 10 sources. The Wesgo Georo datasheet (2018) added density, yield strength, tensile strength and elongation on 2026-11-02. No peer-reviewed phase-diagram source was added.'
story:
  recipe:
    line: Au88Ge12 is a gold-germanium eutectic alloy. Lucas-Milhaupt prints a nominal composition of Gold 88.00 and Germanium 12.00, and Goodfellow describes it as about 88 atomic percent gold and 12 atomic percent germanium. Goodfellow supplies it as as-rolled foil and sheet.
    parts:
      - name: Gold
        symbol: Au
        share_percent: 88
        role: The main constituent. The Goodfellow article says the alloy forms fine intermetallic compounds distributed within a gold matrix.
      - name: Germanium
        symbol: Ge
        share_percent: 12
        role: The eutectic element. The Goodfellow article says this ratio achieves an optimized melting point of 356 °C.
  risk_groups:
    - title: For people
      level: 0
      verdict: Not classified in the supplier safety data sheet
      lead: The supplier safety data sheet for the solid alloy classifies it as not hazardous, but its toxicology entries read Not available.
      points:
        - label: The alloy
          line: Goodfellow's safety data sheet for product AU040 gives no GHS classification and no hazard statements. Treat the alloy as unclassified until a current safety data sheet says otherwise.
        - label: Germanium metal
          line: PubChem lists hazard codes for elemental germanium, including H361 and H373, from company notifications. Those codes apply to germanium, not to the eutectic alloy.
    - title: If the joint overheats
      lead: The only process limit in the sources is the supplier's maximum recommended brazing temperature.
      points:
        - label: Brazing ceiling
          line: Lucas-Milhaupt prints a maximum recommended brazing temperature of 412 °C. The source does not say what happens above that limit.
  why: 'Au88Ge12 is a gold-germanium eutectic alloy used to braze and die-attach electronic parts and to seal hermetic packages. Lucas-Milhaupt prints a melting point of 356 °C for both liquidus and solidus. Suppliers disagree on the figure: the Goodfellow article gives 361 °C for the eutectic reaction, and the Goodfellow datasheet table gives 340-350 °C. The alloy is chosen for a sharp, high-temperature joint with a low vapor pressure filler metal. No space flight or qualification record for it was found in any source we hold.'
  uses:
    - where: Die attach and MEMS packaging
      line: Goodfellow says the foil provides uniform brazing layers for die attach, MEMS packaging and hermetic assemblies. Its product page also lists hermetic optoelectronic modules and cryogenic device assembly.
    - where: Soldering of electronic components
      line: Lucas-Milhaupt says typical applications include soldering of electronic components requiring low vapor pressure filler metal, and it lists controlled atmosphere and vacuum as heating methods.
  can_do:
    - label: Melting point
      benchmark: melting_point
      value: 356 °C
      line: Lucas-Milhaupt prints liquidus and solidus both at 356 °C for PREMABRAZE 880.
    - label: Heat flow
      benchmark: thermal_conductivity
      value: 44 W m-1 K-1 at 23 °C
      line: The Goodfellow datasheet prints 44 W m-1 K-1 at 23 °C. A Goodfellow article gives approximately 30 W m-1 K-1 with no temperature.
    - label: Strength
      benchmark: ultimate_tensile_strength
      value: 185 MPa
      line: The Goodfellow datasheet prints a tensile strength of 185 MPa for as-rolled foil or sheet.
  compare: This profile does not rank Au88Ge12 against other solders on numbers, because no comparison table with other alloys was found in the sources we hold. Goodfellow's article claims that, compared with traditional tin-based solders, Au-Ge alloys provide better conductivity, minimal interdiffusion and improved reliability over time. That is a supplier claim, not a measured comparison.
  compare_rows:
    - label: Melting point
      benchmark: melting_point
    - label: Thermal conductivity
      benchmark: thermal_conductivity
    - label: Tensile strength
      benchmark: ultimate_tensile_strength
  handling:
    - Store the foil in its original container, dry and cool, away from direct sunlight and incompatible materials (Goodfellow safety data sheet, Section 7).
    - Braze at or below the maximum recommended brazing temperature of 412 °C (Lucas-Milhaupt).
    - Dispose of waste through a licensed contractor (Goodfellow safety data sheet, Section 13).
  good_for:
    - Brazing and die attach of electronic parts where a melting point of 356 °C is wanted (Lucas-Milhaupt).
    - Heat flow through a joint, at 44 W m-1 K-1 at 23 °C in the Goodfellow datasheet.
  watch_out:
    - 'Three melting figures appear across sources: 340-350 °C (Goodfellow datasheet table), 356 °C (Lucas-Milhaupt and the Goodfellow product description) and 361 °C (Goodfellow article, eutectic reaction).'
    - 'No measured corrosion test was found: the corrosion and oxidation resistance are supplier claims.'
    - Germanium metal carries PubChem hazard codes, H361 and H373. The alloy's own safety data sheet does not classify it, so check the sheet for the lot you buy.
  verdict: Au88Ge12 has a eutectic melting point printed as 356 °C by Lucas-Milhaupt and a datasheet with thermal and tensile values. Suppliers print the melting point differently, the thermal conductivity has two values, and no space test record was found. It suits electronic die attach where those figures are acceptable.