Menu (ESC)

90-Platinum 10-Iridium Electrical Contact Alloy

90-platinum 10-iridium is a precious metal alloy formulated for use in electrical contacts. It has a moderately high density among the precious metal electrical contact alloys in the database.

The properties of 90-platinum 10-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 90-platinum 10-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

200 GPa 30 x 106 psi

Elongation at Break

5.5 to 34 %

Poisson's Ratio


Shear Modulus

74 GPa 11 x 106 psi

Shear Strength

220 to 320 MPa 31 to 46 x 103 psi

Tensile Strength: Ultimate (UTS)

330 to 550 MPa 47 to 79 x 103 psi

Other Material Properties


22 g/cm3 1340 lb/ft3

Latent Heat of Fusion

100 J/g

Specific Heat Capacity

130 J/kg-K 0.032 BTU/lb-°F

Thermal Expansion

8.6 µm/m-K

Common Calculations

Stiffness to Weight: Axial

5.3 points

Stiffness to Weight: Bending

9.1 points

Strength to Weight: Axial

4.2 to 7.1 points

Strength to Weight: Bending

4.9 to 6.9 points

Thermal Shock Resistance

13 to 22 points

Alloy Composition

Platinum (Pt)Pt 89.3 to 90.5
Iridium (Ir)Ir 9.5 to 10.5
Residualsres. 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