Precious Metal BAu-1
UNS P00375
BAu-1 (P00375) is a 37.5% Au-62.5% Cu gold-copper braze filler of the BAu family, close to the Au-Cu eutectic composition.
Reference datasheet — BAu-1 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
BAu-1 tempers and conditions
BAu-1 is supplied in one standard condition, AS-BRAZED.
Supply forms, finishes and certifications
Ways BAu-1 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FOIL | Foil / Ribbon | Supply form |
POWDER-PASTE | Atomized powder / brazing paste | Supply form |
PREFORM | Stamped preform / washer / ring | Supply form |
Wire-AnnDefault | Wire / Rod | Supply form |
What is BAu-1?
BAu-1 (P00375) is a 37.5% Au-62.5% Cu gold-copper braze filler of the BAu family, close to the Au-Cu eutectic composition. Supplied as annealed wire, foil down to 0.025 mm, stamped preforms, powder and paste, it produces high-strength, vacuum-tight joints in electronic housings, aerospace hardware and Kovar-to-metal seals; the filler shows about 180 MPa yield, 350 MPa tensile and 28% elongation. It needs a furnace cycle at 1020-1090 °C in vacuum or dry hydrogen, so base metals must tolerate that temperature. BAu-2 is used where a higher-gold, more oxidation-resistant fillet is required. BAu-1 has a density of 11.4 g/cm³ (0.412 lb/in³), heavier than 62% of precious metal grades. It melts at 990°C (1,814 °F). BAu-1 has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 59% of precious metal grades. Elongation at break is 28% and the elastic modulus is 105 GPa (15.2 Msi).
What is BAu-1 used for?
- Vacuum-tight electronic housings
- Aerospace component brazing
- High-temperature furnace parts
- Kovar-to-metal seals
BAu-1 properties
Typical room-temperature values; bars are the position among precious metal grades.
Physical3
BAu-1 has a density of 11.4 g/cm³ (0.412 lb/in³), heavier than 62% of precious metal grades. It melts at 990°C (1,814 °F).
Mechanical9
BAu-1 has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 59% of precious metal grades. Elongation at break is 28% and the elastic modulus is 105 GPa (15.2 Msi).
Thermal6
BAu-1 is rated for continuous service to 425°C (797 °F). It conducts heat at 65 W/m·K (37.6 BTU/hr·ft·°F), worse than 67% of precious metal grades. Thermal expansion is 16 µm/m·K (8.89 µin/in·°F).
Electrical3
BAu-1 conducts electricity at 17 % IACS, worse than 56% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 61% of precious metal grades.
Sustainability4
Producing a kilogram of BAu-1 takes about 94,000 MJ of energy and emits 6,800 kg of CO₂ — more than 67% of precious metal grades. Typical recycled content is 50%.
Manufacturability4
BAu-1's machinability is fair (45/100, better than 59% of precious metal grades); formability very good (80/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the precious metal family
Yield strength against density for every precious metal grade FabDigit runs. BAu-1 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BAu-1
Is BAu-1 easy to machine?
Effectively no machining stock; preforms are blanked, sheared or laser cut from foil. Collect all offcuts and scrap for refining.
Can BAu-1 be welded?
This is a braze filler, not a weld consumable. Braze in vacuum below 1×10⁻⁴ mbar or in dry hydrogen with dew point at or below -50 °C at 1020-1090 °C, holding as briefly as possible to limit erosion of the base metal.
Can BAu-1 be formed, bent or molded?
Good ductility in the annealed condition (formability score 85): draws to fine wire, rolls to 0.025 mm foil and coils into rings. Intermediate anneal at 600-700 °C after heavy cold reduction.
BAu-1 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| AuAWS A5.8 BAu-1 | 37 – 38 | 37.5 |
| Other (total)upper limit on total impurities | ≤ 0.15 | |
| Cu | balance |
What surface finishes work on BAu-1?
The joint surface is pale gold and can be polished directly. Remove all flux residue before gold or nickel plating, and degrease and de-oxidise base metals before brazing.
Equivalent designations
Standards and trade names that resolve to Precious Metal BAu-1 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- P00375
- Also called
- AWS BAu-1
How much does BAu-1 cost?
BAu-1 is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
BAu-1 — frequently asked
What is BAu-1 used for?
BAu-1 is typically used for vacuum-tight electronic housings, aerospace component brazing, high-temperature furnace parts and kovar-to-metal seals. In short: strongest gold-copper filler; vacuum-tight hermetic joints; lower gold than BAu-2.
What is the yield strength of BAu-1?
BAu-1 has a typical yield strength of 180 MPa (26.1 ksi) and a tensile strength of 350 MPa (50.8 ksi) — weaker than 59% of precious metal grades.
Is BAu-1 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 59% of precious metal grades). Effectively no machining stock; preforms are blanked, sheared or laser cut from foil. Collect all offcuts and scrap for refining.
Can BAu-1 be welded?
This is a braze filler, not a weld consumable. Braze in vacuum below 1×10⁻⁴ mbar or in dry hydrogen with dew point at or below -50 °C at 1020-1090 °C, holding as briefly as possible to limit erosion of the base metal.
What surface finishes work on BAu-1?
The joint surface is pale gold and can be polished directly. Remove all flux residue before gold or nickel plating, and degrease and de-oxidise base metals before brazing.
Can BAu-1 be formed, bent or molded?
Good ductility in the annealed condition (formability score 85): draws to fine wire, rolls to 0.025 mm foil and coils into rings. Intermediate anneal at 600-700 °C after heavy cold reduction.
What is the maximum service temperature of BAu-1?
BAu-1 is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does BAu-1 cost?
BAu-1 is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- AWS A5.8M/A5.8 Specification for Filler Metals for Brazing and Braze Welding — American Welding Society (2019)
- ASM Handbook Vol.6 — Welding, Brazing, and Soldering (Precious Metal Filler Metals) — ASM International (1993)
- Gold-copper brazing alloy (37.5Au) data sheet — Lucas-Milhaupt / Morgan Advanced Materials (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.