Platinum Alloys
Platinum Alloys:


Nominal Compositions Pt Ir - Pt 90% Ir 10% & Pt 80% Ir 20%

Physical Properties  

Annealed Condition





90/10 Plat Iridium


80/20 Plat Iridium




21.53 g/cc


21.61 g/cc

Mechanical Properties  

Ultimate Tensile Strength


55,100 PSI


100,000 PSI

Electrical Resistivity


.000025 ohm-cm


.000031 ohm-cm

Hardness Brinell






The alloy Platinum Iridium 90/10 containing 10% Iridium has very good all round manufacturing characteristics: it can be cast, welded, machined and stamped; it is ductile and malleable; can be work hardened; and does not readily oxidise. Because of these advantages Pt Ir 90/10 has traditionally been one of the most important jewellery alloys used. although there has recently been a swing toward alloys of Pt Ir 95/5. Some manufacturers in Germany and Japan also prefer the Pt Ir 95/5 alloy. The Pt Ir 80/20 Alloy is very hard and dense, and is sometimes used in the production of fine wirework.

Some uses for platinum iridium alloys include pacemakers, used to treat heart disorders that result in slow or irregular heartbeat, usually contain at least two platinum-iridium electrodes, through which pulses of electricity are transmitted to stabilise the heartbeat.

Other uses of platinum iridium alloys include electrical contacts, spark plugs, electro explosive devices, medical leads and electrodes, thermistors, catalytic applications, jeweller, pen points, surgical pins or pivots and the kilogram and meter standards used by the department of weights and measures.



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