85-Platinum 15-Iridium Electrical Contact Alloy
85-platinum 15-iridium is a precious metal alloy formulated for use in electrical contacts. It has a moderately high density among precious metal electrical contact alloys. In addition, it has the highest melting temperature and a moderately low electrical conductivity.
The properties of 85-platinum 15-iridium 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 85-platinum 15-iridium 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
220 GPa 32 x 106 psi
Elongation at Break
5.5 to 34 %
Poisson's Ratio
0.38
Shear Modulus
81 GPa 12 x 106 psi
Shear Strength
370 to 420 MPa 54 to 61 x 103 psi
Tensile Strength: Ultimate (UTS)
560 to 730 MPa 80 to 110 x 103 psi
Thermal Properties
Latent Heat of Fusion
110 J/g
Melting Completion (Liquidus)
1820 °C 3310 °F
Melting Onset (Solidus)
1790 °C 3250 °F
Specific Heat Capacity
130 J/kg-K 0.032 BTU/lb-°F
Thermal Expansion
8.4 µm/m-K
Other Material Properties
Density
22 g/cm3 1350 lb/ft3
Electrical Conductivity: Equal Volume
6.2 % IACS
Electrical Conductivity: Equal Weight (Specific)
2.6 % IACS
Common Calculations
Stiffness to Weight: Axial
5.7 points
Stiffness to Weight: Bending
9.3 points
Strength to Weight: Axial
7.1 to 9.3 points
Strength to Weight: Bending
6.9 to 8.3 points
Thermal Shock Resistance
21 to 28 points
Alloy Composition
Pt | 84.3 to 85.5 | |
Ir | 14.5 to 15.5 | |
res. | 0 to 0.2 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B684: Standard Specification for Platinum-Iridium Electrical Contact Materials