Precious Metal BAu-5
UNS P00300
BAu-5 is a quaternary precious-metal braze filler of 30%Au-34%Ag-34%Cu-2%Zn (UNS P00300), supplied as wire, foil, powder, paste and as-brazed preforms.
Reference datasheet — BAu-5 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 AB condition
BAu-5 tempers and conditions
BAu-5 is supplied in one standard condition, AB. AB is the default FabDigit quotes; the values on this page are for it.
Supply forms, finishes and certifications
Ways BAu-5 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 |
PWD | Powder | Supply form |
WIRE | Wire / rod | Supply form |
PASTE | Powder plus organic binder, syringe or screen dispensable | Printing process |
What is BAu-5?
BAu-5 is a quaternary precious-metal braze filler of 30%Au-34%Ag-34%Cu-2%Zn (UNS P00300), supplied as wire, foil, powder, paste and as-brazed preforms. The reduced gold fraction lowers cost relative to high-gold BAu grades while retaining good flow and wetting, which suits precision electronic and jewelry-grade brazing. As-brazed strength is about 480 MPa tensile with 10% elongation and a maximum service temperature of 800 °C. The zinc content rules it out for high-vacuum electron devices, where a BVAu vacuum-grade filler is the correct alternative. BAu-5 has a density of 11.9 g/cm³ (0.43 lb/in³), heavier than 64% of precious metal grades. It melts at 1,135°C (2,075 °F). BAu-5 has a tensile strength of 480 MPa (69.6 ksi), stronger than 87% of precious metal grades. Elongation at break is 10% and the elastic modulus is 150 GPa (21.8 Msi).
What is BAu-5 used for?
- Precision electronic assemblies
- Instrument brazing
- Jewelry and decorative metalwork
- Low-temperature hermetic seals
Advantages
- High service temperature — 800°C (1,472 °F), better than 90% of precious metal grades
- Stiff — 150 GPa (21.8 Msi), better than 87% of precious metal grades
Limitations
- Limited ductility — 10%, worse than 89% of precious metal grades
BAu-5 properties
Typical room-temperature values for BAu-5-AB; bars are the position among precious metal grades.
Physical3
BAu-5 has a density of 11.9 g/cm³ (0.43 lb/in³), heavier than 64% of precious metal grades. It melts at 1,135°C (2,075 °F).
Mechanical6
BAu-5 has a tensile strength of 480 MPa (69.6 ksi), stronger than 87% of precious metal grades. Elongation at break is 10% and the elastic modulus is 150 GPa (21.8 Msi).
Thermal4
BAu-5 is rated for continuous service to 800°C (1,472 °F). Thermal expansion is 14.5 µm/m·K (8.06 µin/in·°F).
Electrical1
Chemical & Environmental2
Corrosion resistance is excellent (88/100), better than 67% of precious metal grades.
Sustainability1
Typical recycled content is 60%.
Manufacturability2
Common Calculations2
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-5 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BAu-5
Is BAu-5 easy to machine?
Not a structural machining stock; filler slugs and preforms are stamped, sheared or drawn rather than cut, and all swarf must be captured for precious-metal recovery.
Can BAu-5 be welded?
Applied by furnace brazing in vacuum or dry hydrogen at about 1180–1230 °C with tight 0.03–0.08 mm joint clearances; avoid flux and avoid on base metals whose heat treatment is degraded above 1150 °C.
Can BAu-5 be formed, bent or molded?
Ductile enough to be drawn to fine wire and rolled to thin foil, then stamped into rings and washer preforms with intermediate annealing.
BAu-5 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 |
|---|---|---|
| Augold | 29.5 – 30.5 | 30 |
| Pdpalladium | 33.5 – 34.5 | 34 |
| Other (total)total of all other elements per AWS A5.8 | ≤ 0.15 | |
| Ni | balance |
What surface finishes work on BAu-5?
As-brazed fillets are bright and need little cleanup; joints can be lightly polished or passivated with the base metal, and the noble surface accepts subsequent plating without a strike in most cases.
Equivalent designations
Standards and trade names that resolve to Precious Metal BAu-5 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- P00300
- Also called
- AWS BAu-5
How much does BAu-5 cost?
BAu-5 is a high-cost precious metal ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
BAu-5 — frequently asked
What is BAu-5 used for?
BAu-5 is typically used for precision electronic assemblies, instrument brazing, jewelry and decorative metalwork and low-temperature hermetic seals. In short: lowest-gold BAu filler; cost-reduced precious braze; bright as-brazed fillets.
What is the tensile strength of BAu-5?
BAu-5 has a typical tensile strength of 480 MPa (69.6 ksi) — stronger than 87% of precious metal grades.
Is BAu-5 easy to machine?
Not a structural machining stock; filler slugs and preforms are stamped, sheared or drawn rather than cut, and all swarf must be captured for precious-metal recovery.
Can BAu-5 be welded?
Applied by furnace brazing in vacuum or dry hydrogen at about 1180–1230 °C with tight 0.03–0.08 mm joint clearances; avoid flux and avoid on base metals whose heat treatment is degraded above 1150 °C.
What surface finishes work on BAu-5?
As-brazed fillets are bright and need little cleanup; joints can be lightly polished or passivated with the base metal, and the noble surface accepts subsequent plating without a strike in most cases.
Can BAu-5 be formed, bent or molded?
Ductile enough to be drawn to fine wire and rolled to thin foil, then stamped into rings and washer preforms with intermediate annealing.
What is the maximum service temperature of BAu-5?
BAu-5 is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does BAu-5 cost?
BAu-5 is a high-cost precious metal ($$$$), 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)
- Unified Numbering System for Metals and Alloys (UNS P00300) — SAE/ASTM (2017)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- Gold-based brazing filler metals data sheets — Morgan Advanced Materials (Wesgo Metals) / Lucas-Milhaupt (2022)
- GB/T 18762 (Precious metal brazing filler metals) — SAC (2017)
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.