Iridium
Iridium is an extremely rare, corrosion-resistant platinum group metal (PGM) with exceptional hardness and a melting point above 2400°C. In automotive and clean-energy systems it is used in spark-plug electrodes, catalytic and electrocatalytic coatings, and proton-exchange membrane (PEM) electrolyser anodes.
Overview
Iridium (symbol Ir, atomic number 77) is the densest and among the most corrosion-resistant of the platinum group metals, with a density of about 22.56 g/cm³ and a melting point near 2446°C. It is recovered almost exclusively as a byproduct of platinum and nickel mining, with primary supply concentrated in South Africa and Russia. In spark-ignition engines, iridium or iridium-alloy tip electrodes enable fine-wire plugs that maintain gap geometry longer than conventional nickel designs, supporting colder starts, leaner mixtures and longer service intervals. Beyond ICE, iridium oxide (IrO2) remains the preferred oxygen-evolution reaction (OER) catalyst for PEM water electrolysers used in green hydrogen programmes feeding fuel-cell and synthetic-fuel roadmaps. Iridium also appears in high-temperature thermocouples, crucibles for crystal growth and specialised electrical contacts. Extreme scarcity and high price make thrifting, recycling and alternative OER catalysts active R&D themes for OEMs and Tier-1s specifying iridium-bearing components.
Automotive Applications
Similar Materials
Ruthenium
Platinum Group Metal (PGM)
Ruthenium is a hard, silvery platinum group metal used as a catalyst promoter, electrode coating and alloying addition. In automotive and mobility contexts it supports exhaust aftertreatment, electrochemical devices and specialised electronic contacts.
Tin
Post-transition Metal
Tin is a soft, corrosion-resistant post-transition metal used as the base metal for solders, tinplate coatings and bronze alloys. This entry covers elemental and primary tin feedstock, separate from specialised tin-silver solder alloy grades.
Zirconia / YSZ
Technical Ceramic / Oxygen Sensor
Yttria-stabilised zirconia (YSZ) is a technical ceramic that conducts oxygen ions at elevated temperature, making it the standard solid electrolyte for automotive oxygen (lambda) sensors and related exhaust sensing.
Praseodymium
Rare Earth Element
A light rare-earth metal co-produced with neodymium and used primarily in NdPr (didymium) feedstock for NdFeB permanent magnets that power EV traction motors and automotive actuators.
Properties
Category
Type
Platinum Group Metal (PGM)
Available Colors
Available Forms
Key Properties
- Extremely high corrosion and oxidation resistance
- Melting point ~2446°C
- Highest density among PGMs (~22.56 g/cm³)
- Excellent electrode durability in spark plugs
- Preferred OER catalyst precursor for PEM electrolysers
- Byproduct-constrained, geopolitically concentrated supply
Technical Specifications
Density
22.56 g/cm³
Tensile Strength
~2000–2500 MPa (annealed wire/rod grades vary)
Temperature Resistance
Melts ~2446°C; spark-plug tips and IrO2 catalysts endure continuous high-temperature oxidative environments
Sustainability
Sustainability Rating
Primary supply is a scarce byproduct of PGM mining with high environmental and geopolitical concentration (South Africa, Russia). Closed-loop recycling of spent spark plugs, catalysts and electrolyser MEAs is critical but volumes remain small. Thrifting and Ir-lean OER catalysts are priority sustainability levers.