PtIr20: Soft Annealed Platinum‑Iridium Alloy for High‑Performance Switches and Aerospace Applications

The platinum-iridium material PtIr20 (in the literature also: Pt20Ir, Pt80Ir20, Pt / Ir80 / 20) is used for switch contacts as well as for laboratory devices or structural components such as eg. B. satellite control nozzles that are mechanically stressed, thermally and corrosively heavily used. The mechanical, thermal and corrosive resistance increases with increasing iridium content. In an oxidizing atmosphere, increased weight loss occurs in platinum-iridium alloys. PtIr20 is used for switches and relays for higher AC loads (currents over 300 mA at voltages above 12 V) with a long service life. Another field of application for this material is the use as a potentiometer alloy.

Properties

General

Property	Temperature	Value
Density	20.0 °C	21.7 g/cm³

Mechanical

Property	Temperature	Value	Comment
Elastic modulus	20.0 °C	230 GPa
Elongation	20.0 °C	21 %
Hardness, Vickers	20.0 °C	190 [-]
Poisson's ratio	23.0 °C	0.39 [-]	Typical for Platinum
Shear modulus	23.0 °C	62 GPa	Typical for Platinum
Tensile strength	20.0 °C	570 MPa
Yield strength Rp0.2	20.0 °C	380 MPa

Thermal

Property	Temperature	Value	Comment
Coefficient of thermal expansion	100.0 °C	8.3E-6 1/K
Melting point		1769 °C	Typical for Platinum
Specific heat capacity	23.0 °C	136 J/(kg·K)	Typical for Platinum
Thermal conductivity	23.0 °C	69 - 73 W/(m·K)	Typical for Platinum

Electrical

Property	Temperature	Value
Electrical resistivity	20.0 °C	3.1E-7 Ω·m

Chemical properties

Property	Value
Iridium	20 %
Platinum	80 %

PtIr20 Alloy: Superior Performance in High‑Stress, High‑Temperature, and Corrosive Environments PtIr30: Advanced Platinum‑Iridium Alloy for High‑Performance Switching Contacts

Metal