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AWS BAu-5 (P00300) Filler Metal

AWS BAu-5 is a gold-based filler metal for brazing. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. BAu-5 is the AWS designation for this material. P00300 is the UNS number.

It has a moderately low density among gold-based braze fillers. In addition, it has a fairly high melting temperature and a moderately high tensile strength.

The graph bars on the material properties cards below compare AWS BAu-5 to: gold-based braze fillers (top), all alloys in the same category (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Thermal Properties

Brazing Temperature

1170 to 1230 °C 2130 to 2250 °F

Latent Heat of Fusion

180 J/g

Melting Completion (Liquidus)

1170 °C 2130 °F

Melting Onset (Solidus)

1140 °C 2080 °F

Specific Heat Capacity

280 J/kg-K 0.067 BTU/lb-°F

Thermal Expansion

12 µm/m-K

Other Material Properties


13 g/cm3 820 lb/ft3

Elastic (Young's, Tensile) Modulus

140 GPa 20 x 106 psi

Poisson's Ratio


Shear Modulus

50 GPa 7.2 x 106 psi

Tensile Strength: Ultimate (UTS)

210 MPa 30 x 103 psi

Common Calculations

Stiffness to Weight: Axial

5.8 points

Stiffness to Weight: Bending

13 points

Strength to Weight: Axial

4.5 points

Strength to Weight: Bending

6.0 points

Thermal Shock Resistance

9.0 points

Alloy Composition

Nickel (Ni)Ni 35.5 to 36.4
Palladium (Pd)Pd 33.5 to 34.5
Gold (Au)Au 29.5 to 30.5
Residualsres. 0 to 0.15

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Further Reading

AWS A5.8: Specification for Filler Metals for Brazing and Braze Welding