ASTM B522 Class II Gold-Silver-Platinum Electrical Contact Alloy
ASTM B522 class II is a precious metal alloy formulated for use in electrical contacts.
The properties of ASTM B522 class II include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare ASTM B522 class II to: precious metal electrical contact alloys (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.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
96 GPa 14 x 106 psi
Elongation at Break
1.1 to 28 %
Knoop Hardness
88 to 150
Poisson's Ratio
0.41
Shear Modulus
34 GPa 5.0 x 106 psi
Shear Strength
180 to 280 MPa 26 to 40 x 103 psi
Tensile Strength: Ultimate (UTS)
280 to 490 MPa 40 to 70 x 103 psi
Tensile Strength: Yield (Proof)
120 to 210 MPa 17 to 30 x 103 psi
Thermal Properties
Latent Heat of Fusion
77 J/g
Melting Completion (Liquidus)
1030 °C 1890 °F
Melting Onset (Solidus)
1030 °C 1880 °F
Specific Heat Capacity
160 J/kg-K 0.037 BTU/lb-°F
Thermal Expansion
15 µm/m-K
Other Material Properties
Density
17 g/cm3 1070 lb/ft3
Electrical Conductivity: Equal Volume
11 % IACS
Electrical Conductivity: Equal Weight (Specific)
5.7 % IACS
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
4.4 to 63 MJ/m3
Resilience: Unit (Modulus of Resilience)
75 to 230 kJ/m3
Stiffness to Weight: Axial
3.1 points
Stiffness to Weight: Bending
8.9 points
Strength to Weight: Axial
4.4 to 7.8 points
Strength to Weight: Bending
5.5 to 8.0 points
Thermal Shock Resistance
13 to 24 points
Alloy Composition
| Au | 68.5 to 69.5 | |
| Ag | 24.5 to 25.5 | |
| Pt | 5.5 to 6.5 | |
| S | 0 to 0.010 | |
| res. | 0 to 0.26 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B522: Standard Specification for Gold-Silver-Platinum Electrical Contact Alloy
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015