Precious Metal BVAu-2
UNS P00807
BVAu-2 is the vacuum-service version of the 80%Au-20%Cu braze filler (UNS P00807), with volatile impurities held low so the alloy shows low vapour pressure in high-vacuum service.
Reference datasheet — BVAu-2 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.
Values for the ANN condition
BVAu-2 tempers and conditions
BVAu-2 is supplied in 3 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard stocked condition for vacuum-brazing preforms, foil and wire where formability and clean surfaces matter. | 200 | 400 | 25 | 130 HB | 15 % IACS |
As built (as printed) | Use these numbers for joint design after vacuum brazing at roughly 900–1010 °C with slow cooling. | 230 | 360 | 20 | 140 HB | 15 % IACS |
Hard drawn / as-rolled | Pick when stiffer wire or spring-back-free ring preforms are needed for automated placement; ductility is reduced. | 520 | 620 | 4 | 195 HB | 14.5 % IACS |
Supply forms, finishes and certifications
Ways BVAu-2 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
PWD | Atomized powder / binder paste | Supply form |
What is BVAu-2?
BVAu-2 is the vacuum-service version of the 80%Au-20%Cu braze filler (UNS P00807), with volatile impurities held low so the alloy shows low vapour pressure in high-vacuum service. It is used for brazing vacuum electron devices and spacecraft hardware and is stocked annealed, hard, as-brazed and as powder, plus rolled foil and stamped preforms. Typical properties are 200 MPa yield, 400 MPa tensile and 25% elongation, with a formability rating of 90 and low machinability (40). Gold content dominates cost, so standard BAu-2 is used where vacuum cleanliness control is not required. BVAu-2 has a density of 15.9 g/cm³ (0.574 lb/in³), heavier than 81% of precious metal grades. It melts at 889°C (1,632 °F). BVAu-2 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 51% of precious metal grades. Elongation at break is 25% and the elastic modulus is 92 GPa (13.3 Msi).
What is BVAu-2 used for?
- High-vacuum tube assemblies
- Satellite and spacecraft hardware
- Klystron and traveling-wave tube brazing
- Ultra-high-vacuum instrumentation
Advantages
- Good corrosion resistance — 93/100, better than 77% of precious metal grades
Limitations
- High embodied carbon — 14,000 kg CO₂/kg, worse than 88% of precious metal grades
- Heavy — 15.9 g/cm³ (0.574 lb/in³), worse than 81% of precious metal grades
- Poor heat conductor — 55 W/m·K (31.8 BTU/hr·ft·°F), worse than 76% of precious metal grades
BVAu-2 properties
Typical room-temperature values for BVAu-2-ANN; bars are the position among precious metal grades.
Physical3
BVAu-2 has a density of 15.9 g/cm³ (0.574 lb/in³), heavier than 81% of precious metal grades. It melts at 889°C (1,632 °F).
Mechanical13
BVAu-2 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 51% of precious metal grades. Elongation at break is 25% and the elastic modulus is 92 GPa (13.3 Msi).
Thermal6
BVAu-2 is rated for continuous service to 400°C (752 °F). It conducts heat at 55 W/m·K (31.8 BTU/hr·ft·°F), worse than 76% of precious metal grades. Thermal expansion is 15.9 µm/m·K (8.83 µin/in·°F).
Electrical3
BVAu-2 conducts electricity at 15 % IACS, worse than 65% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is excellent (93/100), better than 77% of precious metal grades.
Sustainability4
Producing a kilogram of BVAu-2 takes about 200,000 MJ of energy and emits 14,000 kg of CO₂ — more than 85% of precious metal grades. Typical recycled content is 70%.
Manufacturability8
BVAu-2's machinability is fair (40/100, worse than 60% of precious metal grades); weldability good (60/100); formability excellent (90/100).
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. BVAu-2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BVAu-2
Is BVAu-2 easy to machine?
Soft and gummy — use sharp, polished, high-rake carbide tooling, light cuts and full scrap recovery; machining is rare since preforms are stamped.
Can BVAu-2 be welded?
Not a structural weld metal; it is applied as a brazing filler at about 900–1010 °C in high vacuum or dry hydrogen, with slow ramping to avoid preform shift and outgassing.
Can BVAu-2 be formed, bent or molded?
Excellent cold formability in the annealed state — rolled to 25–100 µm foil, drawn to fine wire and stamped into washers, rings and shims with interanneals.
BVAu-2 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 |
|---|---|---|
| AuUNS P00807 | 79.5 – 80.5 | 80 |
| Other elements, totalAWS A5.8 impurity limit; vacuum grade additionally restricts high-vapour-pressure elements (Cd, Zn, Pb, P, Mg, S) to trace levels | ≤ 0.15 | |
| Cu | balance |
What surface finishes work on BVAu-2?
Parts are used bare; clean preforms with solvent/ultrasonic degrease only, avoid chlorinated or sulphur-bearing residues, and handle with clean gloves to protect vacuum cleanliness.
Equivalent designations
Standards and trade names that resolve to Precious Metal BVAu-2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- P00807
- Also called
- AWS BVAu-2BAu-2
How much does BVAu-2 cost?
BVAu-2 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.
BVAu-2 — frequently asked
What is BVAu-2 used for?
BVAu-2 is typically used for high-vacuum tube assemblies, satellite and spacecraft hardware, klystron and traveling-wave tube brazing and ultra-high-vacuum instrumentation. In short: vacuum-grade Au-Cu braze; low-outgassing filler; excellent cold formability.
What is the yield strength of BVAu-2?
BVAu-2 has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 51% of precious metal grades. Strength varies by condition: see the 3 listed tempers.
Is BVAu-2 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 60% of precious metal grades). Soft and gummy — use sharp, polished, high-rake carbide tooling, light cuts and full scrap recovery; machining is rare since preforms are stamped.
Can BVAu-2 be welded?
Yes — weldability is rated good (60/100). Not a structural weld metal; it is applied as a brazing filler at about 900–1010 °C in high vacuum or dry hydrogen, with slow ramping to avoid preform shift and outgassing.
What surface finishes work on BVAu-2?
Parts are used bare; clean preforms with solvent/ultrasonic degrease only, avoid chlorinated or sulphur-bearing residues, and handle with clean gloves to protect vacuum cleanliness.
Can BVAu-2 be formed, bent or molded?
Excellent cold formability in the annealed state — rolled to 25–100 µm foil, drawn to fine wire and stamped into washers, rings and shims with interanneals.
What is the maximum service temperature of BVAu-2?
BVAu-2 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between BVAu-2-ANN and BVAu-2-HD?
ANN is the default condition — standard stocked condition for vacuum-brazing preforms, foil and wire where formability and clean surfaces matter. HD: pick when stiffer wire or spring-back-free ring preforms are needed for automated placement; ductility is reduced. Yield strength is 200 MPa in ANN versus 520 MPa in HD.
How much does BVAu-2 cost?
BVAu-2 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 A5.8/A5.8M — Specification for Filler Metals for Brazing and Braze Welding — American Welding Society (2019)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (brazing filler metals) — ASM International (1993)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (precious metals) — ASM International (1990)
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.