Annealed 85-Platinum 15-Iridium Alloy
Annealed 85-platinum 15-iridium is 85-platinum 15-iridium in the annealed condition. The graph bars on the material properties cards below compare annealed 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
34 %
Poisson's Ratio
0.38
Shear Modulus
81 GPa 12 x 106 psi
Shear Strength
370 MPa 54 x 103 psi
Tensile Strength: Ultimate (UTS)
560 MPa 80 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 points
Strength to Weight: Bending
6.9 points
Thermal Shock Resistance
21 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
Further Reading
ASTM B684: Standard Specification for Platinum-Iridium Electrical Contact Materials